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Essential Incident - Almost (Long)

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Ed Anderson

Joined: 10 Jan 2006
Posts: 475

Posted: Wed Jun 03, 2009 11:55 am Post subject: Essential Incident - Almost (Long)

It was suggested by one of the aeroelectric list members, Sam Hoskins,  that the following report of an incident I had on a recent trip be posted to the AeroElectric list for obvious reasons – once you read it.   

   

 I have an all-electric Rv-6A with over 10 years and close to 500 hours on it.  I based the electrical system roughly one of Bob’s excellent designs.   It initially had one alternator and two batteries, but removed the second battery approx 5 years ago – but, I did make one modification to the  design that I almost had cause to regret.  

   

 So needless to say, but I will,  responsibility for design and incident is  totally mine.   

   

But, to get on with the tale  

   

   

One the way to Texas I had an incident that ended up in with me and aircraft making a 7 mile engine-out glide into Craig Field (Selma,  Alabama).  NO!  It was not fault of the engine or even the subsystems.  But, the complete answer is not provided until after my litany of the conditions and symptoms – can you figure it out?  

   

I took off on Thursday (28 May 2009) AM from North Carolina planning on stopping in Mississippi to join up with two friends.  After spending the night there, we all three would then head for Texas.  But, the weather (as you are aware) has been laying over the southeast for days with rain and more rain – but I launched into it anyway as past Atlanta, GA things were forecast to improve..  

   

Other than dodging lines of clouds and a bit of scud running, but not much, I landed at Alexandria City to the southwest of Atlanta, GA to take on fuel.  I then climbed back in and fire it up and took off.    

   

I noticed that during climb-out the engine would occasionally miss and thought the fuel might have had a bit of water in it, but was not really concerned.  So I fly on for approx another 45 minutes and had just passed Selma, Alabama and old Craig Air Force base, and turned west toward Mississippi, when more symptoms began to occur.  

   

It started to act like a case of SAG (fouled spark plugs) where the rpm will drop a bit – not dangerous - just nerve racking.  But, shortly things began to go beyond the SAG symptoms, so I though I might have an injector problem (like one sticking open or not opening at all).  Since our injectors are in pairs, I tried turning one pair off  figuring if things got better, then that pair might have a bad injector.  

   

So I turned off one pair and sure enough the symptoms abated a bit (more on this later) so I figured I had a bad injector in that pair.  To be certain I turned this “bad” pair back on and turn off the “good” pair expecting the symptoms to really get bad as I would now be running on only the “bad” pair – much to my surprise when I turned off the “good” pair – the symptoms also abated.  So that indicated it was not an injector problem – but what?    

   

About this time, I decided to turn the aircraft back around toward Craig Field and dodging clouds headed back with the engine progressively getting worst. It appeared to be a fuel problem (and while that is ultimately the subsystem affected - it was not the root cause).  The fuel pressure was ranging from zero to 80 psi, other electrical things were also misbehaving.  I check the voltmeter thinking perhaps the alternator had died – but it showed 14 volts.  So back to the fuel system.  

   

  Finally, the engine just stops with the prop standing still - like a hood ornament, I’m at around 4500-5000 MSL at this point having lost some altitude dodging a cloud (good old GPS just kept pointing to Craig Field).  At that time I am 6-7 miles out from Craig Field at 4500 msl with a stopped prop, a crippled seat cushion and a dry mouth.  Yes, I’ve been there before, but I don’t think you ever get “use” to it.  I recalled thinking –“… things just can’t get worst…”   when they very shortly and suddenly - did.  

   

I keyed the radio and made a call to Craig Field at 4 miles on the GPS but before I could get their reply, I heard a “CLANK” (without the engine running you can hear things like that)  like a relay springing open (it was) and the entire panel goes dead!!!!   No radio, no engine instruments, not even a stinking LED was lit – only the battery powered GPS.  Can you spell “total electrical failure?”  Talk about a lonely feeling – amazing how comforting having lights on and radio – you could almost convince yourself this was just a practice engine-out landing, but not when the panel goes dark. No engine gauges, no radio, nada!  

   

Well not being one inclined to panic (but I seriously considered it for a moment {:>)), I continued toward Craig field – I mean like there were lots of other alternatives.  Well Once again I found myself in the “fortunate position” of being too high, too much altitude. So I put in 40 degs of flaps to steepen my rate of descent. But, then I decided this time that rather than do the 360 I had done on a previous Incident to lose “excessive” altitude, I would try to glide - a more or less - regular traffic pattern.  

   

However, I neglected to remember to retract the flaps.  So I found myself on the downwind around mid-field at pattern altitude (which felt normal) until I suddenly realized that you CAN NOT maintain that pattern altitude without an engine!!!  (and particularly with 40 deg of flaps deployed – flaps and trim are manual) Duh!  

   

I knew I could never make it to the far end of the runway before turning base (toward the runway) and I was losing altitude at the rate of 400-500 fpm, so I started my turn immediately.   To make matters a bit worst - I had been paralleling the runway on the downwind leg a bit too close in – must have been the comforting feeling of being close to safety.  This position naturally required a tighter turn and as I turned I saw I was likely to overshoot  the runway and land in the grass. So I though I need to steepen this turn further (Yep!  COFFIN CORNER was calling), but fortunately glanced at my airspeed indicator - to see it only registering 80 MPH and my rate of descent (normally 400-500 feet per minute) up to over 1000 feet per minute. The seat cushion suddenly vanished from this universe.  

   

  But the REAL danger in this situation, as you all know, is your airspeed gets low, you are in a steep bank which greatly raises the stall speed  - meaning at 80 mph you are close to a stall in a steep turn while your are not in straight and level.  So I immediately straighten out of the turn – the little voice saying “better to land in the grass than get their concrete runway all messed up”.  So the immediate danger of a stall was adverted, but I was still pointed toward the ground with a sink rate twice as high as normal (and I’ve manage a few hard landings even with a normal sink rate).  Fortunately, the runway was now under my nose rather than grass.  

   

The hardest thing to do when you are sinking at a 1000 fpm a couple hundred feet above the ground (with your nose already pointed at the ground) is to push the stick forward steeping the dive even more.  But, I manage to do that and picked enough air speed and energy to flair to a nice touch down – not even a bump.  I’ve always been amazed at what total concentration does to improve you landing {:>).  

   

Rolled to the end of the runway and had energy to roll off onto the taxiway.   Got out, check under the aircraft for any evidence of leaks and started pulling the aircraft toward the far –off – hangar which had an airplane parked in front of it.  A nice looking young woman comes riding a bicycle out to meet me.  Hopped off and holding out her hand said “Hi I’m Angie, looks like we’ll be spending time together” – so things were starting to look up {:>)  

   

So pulled the aircraft in to the hangar where the mechanic came over and ask what the problem was.  Well, I looked at the volt meter and it said the battery was dead. Mechanic put on a battery charger and announced “Yep! The battery is dead”.  So we both concluded that the alternator must have failed and not being able to replenish the drain on the battery by all the electrical systems such as fuel pumps, injectors, ignition coils, etc had drained the battery.    

   

However, there were a few problems with the analysis of a failed alternator.  First, the low voltage warning light never came on to warn of an alternator problem, 2nd I never notice the voltmeter showing anything other than what it should for alternator voltage – like around 14 volts.  While checking the voltage after the Mechanic had charged the battery, I noticed down below that the “essential bus” switch was in the battery rather than the alternator position, so flicked it back to the alternator position figuring I must have accidentally kicked it while getting to some stuff in the baggage compartment of my RV-6A.  

   

It was getting late and being a bit tired not to mention stressed, I needed to get a rental car and a motel for the night.  Did that, eat dinner and went to bed after sitting down and drawing out a problem tree with the entire major elements of the electrical system.  

   

So next morning I show up at the hangar early and met Ben, the mechanic, the battery had received a charge of only 45 minutes the evening before, So I suggested we charged it for another hour and try to start the aircraft.  Ben suggested a real stress test of the battery and NOT charge it anymore.  Made sense, so we rolled the aircraft out of the hangar.  I hopped in, threw a half dozen switches and punched the starter button.  The engine started on the first prop blade rotation – so the battery was clearly OK. The engine is humming like a top.    So I looked over at the voltmeter expecting it to show only around 12.8 volts instead of the 14 volts a functioning alternator would produce.  Much to both  my and Ben’s surprise the alternator voltage read 14 volts.  We loaded the alternator by turning on the both l00 watt landing lights, all fuel pumps, the pitot heat, etc.  The alternator voltage only drops perhaps 0.4 volts clearly indicating the alternator could carry the load and was OK.  

   

So here I am – battery is OK, alternator is OK – engine is purring normally, so clearly this was all a figment of my deteriorating brain cells.  I loaded up the aircraft and launched to do a few circuits of the airport – I did so and all was operating normally and so I radio them I was head onward to Texas.  While flying (with my only functional eyeball on the voltmeter), my mind could not let go of the problem and finally the light bulb came on.    

   

The essential bus switch had (for my entire 10 + years of flying)always been in the alternator position.  The purpose of this switch is, of course,  to isolate the battery from the alternator should the alternator fail - to prevent an alternator problem from draining the battery.  So in event of an alternator problem, you move the switch from alternator to battery.  Its call the essential bus because you only have the essential things drawing from the battery so you wont’ drain it as quickly.  The idea is to give you time (generally around 30 minutes) to find a safe place to land in case of alternator failure.  

   

   

Well, at some point I had either (not paying attention) turned the switch to battery thinking I was turning the voltmeter switch to battery(more on that below)  - or accidentally had move the switch from alternator to battery without noticing it by kicking it, etc.  However, it was sort of protected in its position from accidental activation. It must have happened during refueling – as I got approx 45 minutes down the road on the battery after take off before quality battery time started to deteriorate.  As the battery voltage fell due to the load (and no alternator link to replenish it), electrical things (mainly computers first) started acting up until they could not longer run the engine. The injectors would not open fully, etc.  Then as the voltage level further decreased, the master relay which the battery held closed and which connected the (fully functional) alternator to the rest of the electrical system - opened up and removed ALL power from the electrical system.  So no radio, no gauges, etc.   

   

 Oh, another little factor that may have contributed, the voltmeter has a tiny toggle switch by it marked ALT BAT1 BAT2 for checking alternator battery 1 and battery 2 (which I no longer fly with) voltages.  Down below It a couple of inches and off to the right is the essential bus normal size toggle switch – also marked ALT BAT1 BAT1.  I normally never touch it and don’t even think about it.  But I could have reached for the voltmeter toggle thinking to check my battery voltage (which I do as a regular thing) and perhaps distracted by something reached a bit further down and instead moved the essential bus switch from Alternator to Battery causing this entire event.  I know that I did not consciously do it.  So it is either accidental or absence minded activation - either way ends with the same results {:>)  

   

   

Now it became clear why it didn’t matter which pair of fuel injectors I turned off – turning off either pair improved the situation because it slightly reduced the electrical load by a few amps – and the engine ran slightly better for a few moments.  The same thing had happened when turning off one of the EFI fuel pumps – but what threw me was the alternator voltage continued to be normal during this.  

   

After I knew the cause (switch in wrong position), I decided the problem was fixed so no reason to return to NC, and I just continued on to Texas.  

   

I know some of you may think that removing my second battery was a mistake – but, consider this, having another battery could have meant I would have been much further from a suitable airfield before they both went south.  On the other hand, it might have caused me to at least think to throw the essential bus switch to the second battery and have the Light bulb come on.  Who really knows.  But, I have in mind a simply addition to my electrical circuit that should help in the future.   

   

   

I do want to state that this time when the problems started I DID switch fuel tanks – but naturally it had no effect because this time it turned out, it was not a fuel problem – not the root cause at least.  

   

So what are the lessons learned:  

     Put      EVERY critical switch on your before-takeoff Check list   
Perhaps      put a guard around such critical switches to force conscious activation        
Don’t      (hard not to) get overly focused on what you think is the problem –      consider other possibilities.  I thought it was a fuel problem (I      even switched fuel tanks this time) – it turned out to be electrical      in its root cause.   
While      the fuel pressure was jumping all over the place and the EGT was erratic      and engine surging strongly indicating a fuel problem – the ultimate      cause was electrical.  Once the voltage got below a certain point the      EC2 computer  was still trying to pull the injectors open, but with      the voltage so low it could not do it properly.   
When      the battery voltage dropped below a certain point, the master relay      released and removed the alternator from the electrical system and the      panel went dark – even though the alternator was still working        
Immediately      turn to the nearest airfield when serious problems occur - THEN work on      fixing them.  I only delayed for perhaps 2-3 minutes, but that could      have made a difference.   
Watch      out for Coffin Corner turn      when turning base to final – airspeed really bleeds off fast with no      engine pulling you along (and especially with flaps deployed!)        
IF      you change your mind about landing approach type - remember to reconfigure      your aircraft for the last decision – I had left my flaps deployed      when I should have remembered to retracted them.  Did that help      prevent a Coffin Corner stall and spin or would it have put me closer to      it?   
You      must increase airspeed over the wing to get the sufficient energy to over      come a high sink rate.  Pulling back on the stick when the ground is      staring you in the face is the natural reaction – but, pushing      forward to lower the nose is the correct action – providing of      course you have sufficient altitude!   
Battery life –      I had a two year old 680 odyssey battery which I maintain a trickle charge      on whenever I’m not flying.  With two EFI fuel pumps, boost      pump, injectors, coils, EC2 and radio and just having started the engine      before take off – this battery lasted 55 minutes.  Well, the      last 5 minutes were not quality battery time.  So in my case, 30      minutes appears to be a very realistic battery life.  In fact, had I      turned off one EFI pump and the boost pump would have gained a few more      miles.  But, if I had recognized the need to turn them off at that      time (I normally turn them off at cruise altitude), then I would have      known how to “fix” the problem.   
I’ve      decided to add a Schokkty diode between my essential bus and the      alternator – so that as long as the alternator is producing      sufficient voltage, then the battery will be getting some charge to      replace the drain.  I’ve also decided to make that switch      position a check-list item.    

   

 So what it boils down to – if I had recognized early on that it was an electrical problem and not focused so much on the fuel system, I may have noticed the essential bus switch in the wrong position.  Force yourself to examine other possible causes (easy to say – harder to do).   

   

NEVER, NEVER forget that flying the airplane is the first and only priority in this type of situation  

   

NEVER, NEVER forget that saving your butt is the ultimately end-all priority.  When I decided that landing on the grass was preferable to putting a hole in their concrete – I  may have made a life-saving decision.  

   

So that’s my story and I’m sticking to it.    

   

Fly safe, guys!!  

   

Ed  

Ed Anderson  

Rv-6A N494BW Rotary Powered  

Matthews, NC  

eanderson(at)carolina.rr.com  

http://www.andersonee.com  

http://www.dmack.net/mazda/index.html  

http://www.flyrotary.com/  

http://members.cox.net/rogersda/rotary/configs.htm#N494BW  

[url=http://www.dmack.net/mazda/index.html][/url]  

   

       [quote][b]

_________________
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com

Sam

Joined: 18 May 2008
Posts: 135

Posted: Wed Jun 03, 2009 12:14 pm Post subject: Essential Incident - Almost (Long)

Ed - great story.  Just out of curiosity, where is the essential bus switch

located?  Is it plainly in your field of vision or do you have to turn your

head to see it?



Cockpit ergonomics are a huge challenge.



Sam Hoskins

www.samhoskins.blogspot.com



On Wed, Jun 3, 2009 at 2:53 PM, Ed Anderson <eanderson(at)carolina.rr.com>wrote:



[quote]  It was suggested by one of the aeroelectric list members, Sam Hoskins,

  that the following report of an incident I had on a recent trip be posted

 to the AeroElectric list for obvious reasons – once you read it.



  I have an all-electric Rv-6A with over 10 years and close to 500 hours on

 it.  I based the electrical system roughly one of Bob’s excellent designs.

  It initially had one alternator and two batteries, but removed the second

 battery approx 5 years ago – but, I did make one modification to the  design

 that I almost had cause to regret.



  So needless to say, but I will,  responsibility for design and incident is

  totally mine.



 But, to get on with the tale



 One the way to Texas I had an incident that ended up in with me and

 aircraft making a 7 mile engine-out glide into Craig Field (Selma,

 Alabama).  NO!  It was not fault of the engine or even the subsystems.  But,

 the complete answer is not provided until after my litany of the conditions

 and symptoms – can you figure it out?



 I took off on Thursday (28 May 2009) AM from North Carolina planning on

 stopping in Mississippi to join up with two friends.  After spending the

 night there, we all three would then head for Texas.  But, the weather (as

 you are aware) has been laying over the southeast for days with rain and

 more rain – but I launched into it anyway as past Atlanta, GA things were

 forecast to improve..



 Other than dodging lines of clouds and a bit of scud running, but not much,

 I landed at Alexandria City to the southwest of Atlanta, GA to take on

 fuel.  I then climbed back in and fire it up and took off.



 I noticed that during climb-out the engine would occasionally miss and

 thought the fuel might have had a bit of water in it, but was not really

 concerned.  So I fly on for approx another 45 minutes and had just passed

 Selma, Alabama and old Craig Air Force base, and turned west toward

 Mississippi, when more symptoms began to occur.



 It started to act like a case of SAG (fouled spark plugs) where the rpm

 will drop a bit – not dangerous - just nerve racking.  But, shortly things

 began to go beyond the SAG symptoms, so I though I might have an injector

 problem (like one sticking open or not opening at all).  Since our injectors

 are in pairs, I tried turning one pair off  figuring if things got better,

 then that pair might have a bad injector.



 So I turned off one pair and sure enough the symptoms abated a bit (more on

 this later) so I figured I had a bad injector in that pair.  To be certain I

 turned this “bad” pair back on and turn off the “good” pair expecting the

 symptoms to really get bad as I would now be running on only the “bad” pair

 – much to my surprise when I turned off the “good” pair – the symptoms also

 abated.  So that indicated it was not an injector problem – but what?



 About this time, I decided to turn the aircraft back around toward Craig

 Field and dodging clouds headed back with the engine progressively getting

 worst. It appeared to be a fuel problem (and while that is ultimately the

 subsystem affected - it was not the root cause).  The fuel pressure was

 ranging from zero to 80 psi, other electrical things were also misbehaving.

 I check the voltmeter thinking perhaps the alternator had died – but it

 showed 14 volts.  So back to the fuel system.



   Finally, the engine just stops with the prop standing still - like a hood

 ornament, I’m at around 4500-5000 MSL at this point having lost some

 altitude dodging a cloud (good old GPS just kept pointing to Craig Field)

_________________
Sam Hoskins
www.samhoskins.blogspot.com

mprather(at)spro.net
Guest

Posted: Wed Jun 03, 2009 12:46 pm Post subject: Essential Incident - Almost (Long)

Great writeup Ed.  Thanks for sharing it with the list.

Regards,



Matt-



 	  Quote: 	
		   It was suggested by one of the aeroelectric list members, Sam Hoskins,

 that

 the following report of an incident I had on a recent trip be posted to

 the

 AeroElectric list for obvious reasons - once you read it.



  I have an all-electric Rv-6A with over 10 years and close to 500 hours on

 it.  I based the electrical system roughly one of Bob's excellent designs.

 It initially had one alternator and two batteries, but removed the second

 battery approx 5 years ago - but, I did make one modification to the

 design

 that I almost had cause to regret.



  So needless to say, but I will,  responsibility for design and incident

 is

 totally mine.



 But, to get on with the tale



 One the way to Texas I had an incident that ended up in with me and

 aircraft

 making a 7 mile engine-out glide into Craig Field (Selma, Alabama).  NO!

 It

 was not fault of the engine or even the subsystems.  But, the complete

 answer is not provided until after my litany of the conditions and

 symptoms

 - can you figure it out?



 I took off on Thursday (28 May 2009) AM from North Carolina planning on

 stopping in Mississippi to join up with two friends.  After spending the

 night there, we all three would then head for Texas.  But, the weather (as

 you are aware) has been laying over the southeast for days with rain and

 more rain - but I launched into it anyway as past Atlanta, GA things were

 forecast to improve..



 Other than dodging lines of clouds and a bit of scud running, but not

 much,

 I landed at Alexandria City to the southwest of Atlanta, GA to take on

 fuel.

 I then climbed back in and fire it up and took off.



 I noticed that during climb-out the engine would occasionally miss and

 thought the fuel might have had a bit of water in it, but was not really

 concerned.  So I fly on for approx another 45 minutes and had just passed

 Selma, Alabama and old Craig Air Force base, and turned west toward

 Mississippi, when more symptoms began to occur.



 It started to act like a case of SAG (fouled spark plugs) where the rpm

 will

 drop a bit - not dangerous - just nerve racking.  But, shortly things

 began

 to go beyond the SAG symptoms, so I though I might have an injector

 problem

 (like one sticking open or not opening at all).  Since our injectors are

 in

 pairs, I tried turning one pair off  figuring if things got better, then

 that pair might have a bad injector.



 So I turned off one pair and sure enough the symptoms abated a bit (more

 on

 this later) so I figured I had a bad injector in that pair.  To be certain

 I

 turned this "bad" pair back on and turn off the "good" pair expecting the

 symptoms to really get bad as I would now be running on only the "bad"

 pair

 - much to my surprise when I turned off the "good" pair - the symptoms

 also

 abated.  So that indicated it was not an injector problem - but what?



 About this time, I decided to turn the aircraft back around toward Craig

 Field and dodging clouds headed back with the engine progressively getting

 worst. It appeared to be a fuel problem (and while that is ultimately the

 subsystem affected - it was not the root cause).  The fuel pressure was

 ranging from zero to 80 psi, other electrical things were also

 misbehaving.

 I check the voltmeter thinking perhaps the alternator had died - but it

 showed 14 volts.  So back to the fuel system.



   Finally, the engine just stops with the prop standing still - like a

 hood

 ornament, I'm at around 4500-5000 MSL at this point having lost some

 altitude dodging a cloud (good old GPS just kept pointing to Craig Field).

 At that time I am 6-7 miles out from Craig Field at 4500 msl with a

 stopped

 prop, a crippled seat cushion and a dry mouth.  Yes, I've been there

 before,

 but I don't think you ever get "use" to it.  I recalled thinking -".

 things

 just can't get worst."   when they very shortly and suddenly - did.



 I keyed the radio and made a call to Craig Field at 4 miles on the GPS but

 before I could get their reply, I heard a "CLANK" (without the engine

 running you can hear things like that)  like a relay springing open (it

 was)

 and the entire panel goes dead!!!!   No radio, no engine instruments, not

 even a stinking LED was lit - only the battery powered GPS.  Can you spell

 "total electrical failure?"  Talk about a lonely feeling - amazing how

 comforting having lights on and radio - you could almost convince yourself

 this was just a practice engine-out landing, but not when the panel goes

 dark. No engine gauges, no radio, nada!



 Well not being one inclined to panic (but I seriously considered it for a

 moment {:>)), I continued toward Craig field - I mean like there were lots

 of other alternatives.  Well Once again I found myself in the "fortunate

 position" of being too high, too much altitude. So I put in 40 degs of

 flaps

 to steepen my rate of descent. But, then I decided this time that rather

 than do the 360 I had done on a previous Incident to lose "excessive"

 altitude, I would try to glide - a more or less - regular traffic pattern.



 However, I neglected to remember to retract the flaps.  So I found myself

 on

 the downwind around mid-field at pattern altitude (which felt normal)

 until

 I suddenly realized that you CAN NOT maintain that pattern altitude

 without

 an engine!!!  (and particularly with 40 deg of flaps deployed - flaps and

 trim are manual) Duh!



 I knew I could never make it to the far end of the runway before turning

 base (toward the runway) and I was losing altitude at the rate of 400-500

 fpm, so I started my turn immediately.   To make matters a bit worst - I

 had

 been paralleling the runway on the downwind leg a bit too close in - must

 have been the comforting feeling of being close to safety.  This position

 naturally required a tighter turn and as I turned I saw I was likely to

 overshoot  the runway and land in the grass. So I though I need to steepen

 this turn further (Yep!  COFFIN CORNER was calling), but fortunately

 glanced

 at my airspeed indicator - to see it only registering 80 MPH and my rate

 of

 descent (normally 400-500 feet per minute) up to over 1000 feet per

 minute.

 The seat cushion suddenly vanished from this universe.



   But the REAL danger in this situation, as you all know, is your airspeed

 gets low, you are in a steep bank which greatly raises the stall speed  -

 meaning at 80 mph you are close to a stall in a steep turn while your are

 not in straight and level.  So I immediately straighten out of the turn -

 the little voice saying "better to land in the grass than get their

 concrete

 runway all messed up".  So the immediate danger of a stall was adverted,

 but

 I was still pointed toward the ground with a sink rate twice as high as

 normal (and I've manage a few hard landings even with a normal sink rate).

 Fortunately, the runway was now under my nose rather than grass.



 The hardest thing to do when you are sinking at a 1000 fpm a couple

 hundred

 feet above the ground (with your nose already pointed at the ground) is to

 push the stick forward steeping the dive even more.  But, I manage to do

 that and picked enough air speed and energy to flair to a nice touch down

 -

 not even a bump.  I've always been amazed at what total concentration does

 to improve you landing {:>).



 Rolled to the end of the runway and had energy to roll off onto the

 taxiway.

 Got out, check under the aircraft for any evidence of leaks and started

 pulling the aircraft toward the far -off - hangar which had an airplane

 parked in front of it.  A nice looking young woman comes riding a bicycle

 out to meet me.  Hopped off and holding out her hand said "Hi I'm Angie,

 looks like we'll be spending time together" - so things were starting to

 look up {:>)



 So pulled the aircraft in to the hangar where the mechanic came over and

 ask

 what the problem was.  Well, I looked at the volt meter and it said the

 battery was dead. Mechanic put on a battery charger and announced "Yep!

 The

 battery is dead".  So we both concluded that the alternator must have

 failed

 and not being able to replenish the drain on the battery by all the

 electrical systems such as fuel pumps, injectors, ignition coils, etc had

 drained the battery.



 However, there were a few problems with the analysis of a failed

 alternator.

 First, the low voltage warning light never came on to warn of an

 alternator

 problem, 2nd I never notice the voltmeter showing anything other than what

 it should for alternator voltage - like around 14 volts.  While checking

 the

 voltage after the Mechanic had charged the battery, I noticed down below

 that the "essential bus" switch was in the battery rather than the

 alternator position, so flicked it back to the alternator position

 figuring

 I must have accidentally kicked it while getting to some stuff in the

 baggage compartment of my RV-6A.



 It was getting late and being a bit tired not to mention stressed, I

 needed

 to get a rental car and a motel for the night.  Did that, eat dinner and

 went to bed after sitting down and drawing out a problem tree with the

 entire major elements of the electrical system.



 So next morning I show up at the hangar early and met Ben, the mechanic,

 the

 battery had received a charge of only 45 minutes the evening before, So I

 suggested we charged it for another hour and try to start the aircraft.

 Ben

 suggested a real stress test of the battery and NOT charge it anymore.

 Made

 sense, so we rolled the aircraft out of the hangar.  I hopped in, threw a

 half dozen switches and punched the starter button.  The engine started on

 the first prop blade rotation - so the battery was clearly OK. The engine

 is

 humming like a top.    So I looked over at the voltmeter expecting it to

 show only around 12.8 volts instead of the 14 volts a functioning

 alternator

 would produce.  Much to both  my and Ben's surprise the alternator voltage

 read 14 volts.  We loaded the alternator by turning on the both l00 watt

 landing lights, all fuel pumps, the pitot heat, etc.  The alternator

 voltage

 only drops perhaps 0.4 volts clearly indicating the alternator could carry

 the load and was OK.



 So here I am - battery is OK, alternator is OK - engine is purring

 normally,

 so clearly this was all a figment of my deteriorating brain cells.  I

 loaded

 up the aircraft and launched to do a few circuits of the airport - I did

 so

 and all was operating normally and so I radio them I was head onward to

 Texas.  While flying (with my only functional eyeball on the voltmeter),

 my

 mind could not let go of the problem and finally the light bulb came on.



 The essential bus switch had (for my entire 10 + years of flying)always

 been

 in the alternator position.  The purpose of this switch is, of course,  to

 isolate the battery from the alternator should the alternator fail - to

 prevent an alternator problem from draining the battery.  So in event of

 an

 alternator problem, you move the switch from alternator to battery.  Its

 call the essential bus because you only have the essential things drawing

 from the battery so you wont' drain it as quickly.  The idea is to give

 you

 time (generally around 30 minutes) to find a safe place to land in case of

 alternator failure.



 Well, at some point I had either (not paying attention) turned the switch

 to

 battery thinking I was turning the voltmeter switch to battery(more on

 that

 below)  - or accidentally had move the switch from alternator to battery

 without noticing it by kicking it, etc.  However, it was sort of protected

 in its position from accidental activation. It must have happened during

 refueling - as I got approx 45 minutes down the road on the battery after

 take off before quality battery time started to deteriorate.  As the

 battery

 voltage fell due to the load (and no alternator link to replenish it),

 electrical things (mainly computers first) started acting up until they

 could not longer run the engine. The injectors would not open fully, etc.

 Then as the voltage level further decreased, the master relay which the

 battery held closed and which connected the (fully functional) alternator

 to

 the rest of the electrical system - opened up and removed ALL power from

 the

 electrical system.  So no radio, no gauges, etc.



  Oh, another little factor that may have contributed, the voltmeter has a

 tiny toggle switch by it marked ALT BAT1 BAT2 for checking alternator

 battery 1 and battery 2 (which I no longer fly with) voltages.  Down below

 It a couple of inches and off to the right is the essential bus normal

 size

 toggle switch - also marked ALT BAT1 BAT1.  I normally never touch it and

 don't even think about it.  But I could have reached for the voltmeter

 toggle thinking to check my battery voltage (which I do as a regular

 thing)

 and perhaps distracted by something reached a bit further down and instead

 moved the essential bus switch from Alternator to Battery causing this

 entire event.  I know that I did not consciously do it.  So it is either

 accidental or absence minded activation - either way ends with the same

 results {:>)



 Now it became clear why it didn't matter which pair of fuel injectors I

 turned off - turning off either pair improved the situation because it

 slightly reduced the electrical load by a few amps - and the engine ran

 slightly better for a few moments.  The same thing had happened when

 turning

 off one of the EFI fuel pumps - but what threw me was the alternator

 voltage

 continued to be normal during this.



 After I knew the cause (switch in wrong position), I decided the problem

 was

 fixed so no reason to return to NC, and I just continued on to Texas.



 I know some of you may think that removing my second battery was a mistake

 -

 but, consider this, having another battery could have meant I would have

 been much further from a suitable airfield before they both went south.

 On

 the other hand, it might have caused me to at least think to throw the

 essential bus switch to the second battery and have the Light bulb come

 on.

 Who really knows.  But, I have in mind a simply addition to my electrical

 circuit that should help in the future.



 I do want to state that this time when the problems started I DID switch

 fuel tanks - but naturally it had no effect because this time it turned

 out,

 it was not a fuel problem - not the root cause at least.



 So what are the lessons learned:



 1.	Put EVERY critical switch on your before-takeoff Check list

 2.	Perhaps put a guard around such critical switches to force conscious

 activation

 3.	Don't (hard not to) get overly focused on what you think is the

 problem - consider other possibilities.  I thought it was a fuel problem

 (I

 even switched fuel tanks this time) - it turned out to be electrical in

 its

 root cause.

 4.	While the fuel pressure was jumping all over the place and the EGT

 was erratic and engine surging strongly indicating a fuel problem - the

 ultimate cause was electrical.  Once the voltage got below a certain point

 the EC2 computer  was still trying to pull the injectors open, but with

 the

 voltage so low it could not do it properly.

 5.	When the battery voltage dropped below a certain point, the master

 relay released and removed the alternator from the electrical system and

 the

 panel went dark - even though the alternator was still working

 6.	Immediately turn to the nearest airfield when serious problems occur

 - THEN work on fixing them.  I only delayed for perhaps 2-3 minutes, but

 that could have made a difference.

 7.	Watch out for Coffin Corner turn when turning base to final -

 airspeed really bleeds off fast with no engine pulling you along (and

 especially with flaps deployed!)

 8.	IF you change your mind about landing approach type - remember to

 reconfigure your aircraft for the last decision - I had left my flaps

 deployed when I should have remembered to retracted them.  Did that help

 prevent a Coffin Corner stall and spin or would it have put me closer to

 it?



 9.	You must increase airspeed over the wing to get the sufficient

 energy to over come a high sink rate.  Pulling back on the stick when the

 ground is staring you in the face is the natural reaction - but, pushing

 forward to lower the nose is the correct action - providing of course you

 have sufficient altitude!

 10.	Battery life - I had a two year old 680 odyssey battery which I

 maintain a trickle charge on whenever I'm not flying.  With two EFI fuel

 pumps, boost pump, injectors, coils, EC2 and radio and just having started

 the engine before take off - this battery lasted 55 minutes.  Well, the

 last

 5 minutes were not quality battery time.  So in my case, 30 minutes

 appears

 to be a very realistic battery life.  In fact, had I turned off one EFI

 pump

 and the boost pump would have gained a few more miles.  But, if I had

 recognized the need to turn them off at that time (I normally turn them

 off

 at cruise altitude), then I would have known how to "fix" the problem.

 11.	I've decided to add a Schokkty diode between my essential bus and

 the alternator - so that as long as the alternator is producing sufficient

 voltage, then the battery will be getting some charge to replace the

 drain.

 I've also decided to make that switch position a check-list item.



  So what it boils down to - if I had recognized early on that it was an

 electrical problem and not focused so much on the fuel system, I may have

 noticed the essential bus switch in the wrong position.  Force yourself to

 examine other possible causes (easy to say - harder to do).



 NEVER, NEVER forget that flying the airplane is the first and only

 priority

 in this type of situation



 NEVER, NEVER forget that saving your butt is the ultimately end-all

 priority.  When I decided that landing on the grass was preferable to

 putting a hole in their concrete - I  may have made a life-saving

 decision.



 So that's my story and I'm sticking to it.



 Fly safe, guys!!



 Ed



 Ed Anderson



 Rv-6A N494BW Rotary Powered



 Matthews, NC



 eanderson(at)carolina.rr.com



  <http://www.andersonee.com> http://www.andersonee.com



  <http://www.dmack.net/mazda/index.html>

 http://www.dmack.net/mazda/index.html



 http://www.flyrotary.com/



  <http://members.cox.net/rogersda/rotary/configs.htm>

 http://members.cox.net/rogersda/rotary/configs.htm#N494BW



  <http://www.dmack.net/mazda/index.html>

khorton01(at)rogers.com
Guest

Posted: Wed Jun 03, 2009 1:11 pm Post subject: Essential Incident - Almost (Long)

Ed,



Congrats for keeping your cool, and flying the airplane to a safe  

landing.  And thanks for sharing the story, so we can all learn from  

your incident.



I fully agree that checklists are important.  If your electrical  

system design assumes that the electrical system will be in a  

particular configuration for flight, then you need a checklist that  

ensures this is true.  And you need to religiously do every step on  

that checklist before take-off.



It is also useful to have well thought out checklists for engine  

failure, engine rough running, etc.  For example, a well thought rough  

running engine checklist would include all steps necessary to check  

voltage on whatever bus(s) your engine needs.



One thing that puzzles me about your electrical system design - it  

seems that your engine needs power from the Essential Bus.  But it  

seems like your active low voltage warning is looking at some other  

bus.  Why not hook the low voltage warning up the the one bus that is  

really important - i.e. the Essential Bus?



Kevin Horton



On 3-Jun-09, at 15:53 , Ed Anderson wrote:



 	  Quote: 	
		   It was suggested by one of the aeroelectric list members, Sam  

 Hoskins,  that the following report of an incident I had on a recent  

 trip be posted to the AeroElectric list for obvious reasons – once  

 you read it.



  I have an all-electric Rv-6A with over 10 years and close to 500  

 hours on it.  I based the electrical system roughly one of Bob’s  

 excellent designs.   It initially had one alternator and two  

 batteries, but removed the second battery approx 5 years ago – but,  

 I did make one modification to the  design that I almost had cause  

 to regret.



  So needless to say, but I will,  responsibility for design and  

 incident is  totally mine.



 But, to get on with the tale

 One the way to Texas I had an incident that ended up in with me and  

 aircraft making a 7 mile engine-out glide into Craig Field (Selma,  

 Alabama).  NO!  It was not fault of the engine or even the  

 subsystems.  But, the complete answer is not provided until after my  

 litany of the conditions and symptoms – can you figure it out?



 I took off on Thursday (28 May 2009) AM from North Carolina planning  

 on stopping in Mississippi to join up with two friends.  After  

 spending the night there, we all three would then head for Texas.   

 But, the weather (as you are aware) has been laying over the  

 southeast for days with rain and more rain – but I launched into it  

 anyway as past Atlanta, GA things were forecast to improve..



 Other than dodging lines of clouds and a bit of scud running, but  

 not much, I landed at Alexandria City to the southwest of Atlanta,  

 GA to take on fuel.  I then climbed back in and fire it up and took  

 off.



 I noticed that during climb-out the engine would occasionally miss  

 and thought the fuel might have had a bit of water in it, but was  

 not really concerned.  So I fly on for approx another 45 minutes and  

 had just passed Selma, Alabama and old Craig Air Force base, and  

 turned west toward Mississippi, when more symptoms began to occur.



 It started to act like a case of SAG (fouled spark plugs) where the  

 rpm will drop a bit – not dangerous - just nerve racking.  But,  

 shortly things began to go beyond the SAG symptoms, so I though I  

 might have an injector problem (like one sticking open or not  

 opening at all).  Since our injectors are in pairs, I tried turning  

 one pair off  figuring if things got better, then that pair might  

 have a bad injector.



 So I turned off one pair and sure enough the symptoms abated a bit  

 (more on this later) so I figured I had a bad injector in that  

 pair.  To be certain I turned this “bad” pair back on and turn off  

 the “good” pair expecting the symptoms to really get bad as I would  

 now be running on only the “bad” pair – much to my surprise when I  

 turned off the “good” pair – the symptoms also abated.  So that  

 indicated it was not an injector problem – but what?



 About this time, I decided to turn the aircraft back around toward  

 Craig Field and dodging clouds headed back with the engine  

 progressively getting worst. It appeared to be a fuel problem (and  

 while that is ultimately the subsystem affected - it was not the  

 root cause).  The fuel pressure was ranging from zero to 80 psi,  

 other electrical things were also misbehaving.  I check the  

 voltmeter thinking perhaps the alternator had died – but it showed  

 14 volts.  So back to the fuel system.



   Finally, the engine just stops with the prop standing still - like  

 a hood ornament, I’m at around 4500-5000 MSL at this point having  

 lost some altitude dodging a cloud (good old GPS just kept pointing  

 to Craig Field).  At that time I am 6-7 miles out from Craig Field  

 at 4500 msl with a stopped prop, a crippled seat cushion and a dry  

 mouth.  Yes, I’ve been there before, but I don’t think you ever get  

 “use” to it.  I recalled thinking –“… things just can’t get  

 worst…”   when they very shortly and suddenly - did.



 I keyed the radio and made a call to Craig Field at 4 miles on the  

 GPS but before I could get their reply, I heard a “CLANK” (without  

 the engine running you can hear things like that)  like a relay  

 springing open (it was) and the entire panel goes dead!!!!   No  

 radio, no engine instruments, not even a stinking LED was lit – only  

 the battery powered GPS.  Can you spell “total electrical failure?”   

 Talk about a lonely feeling – amazing how comforting having lights  

 on and radio – you could almost convince yourself this was just a  

 practice engine-out landing, but not when the panel goes dark. No  

 engine gauges, no radio, nada!



 Well not being one inclined to panic (but I seriously considered it  

 for a moment {:>)), I continued toward Craig field – I mean like  

 there were lots of other alternatives.  Well Once again I found  

 myself in the “fortunate position” of being too high, too much  

 altitude. So I put in 40 degs of flaps to steepen my rate of  

 descent. But, then I decided this time that rather than do the 360 I  

 had done on a previous Incident to lose “excessive” altitude, I  

 would try to glide - a more or less - regular traffic pattern.



 However, I neglected to remember to retract the flaps.  So I found  

 myself on the downwind around mid-field at pattern altitude (which  

 felt normal) until I suddenly realized that you CAN NOT maintain  

 that pattern altitude without an engine!!!  (and particularly with  

 40 deg of flaps deployed – flaps and trim are manual) Duh!



 I knew I could never make it to the far end of the runway before  

 turning base (toward the runway) and I was losing altitude at the  

 rate of 400-500 fpm, so I started my turn immediately.   To make  

 matters a bit worst - I had been paralleling the runway on the  

 downwind leg a bit too close in – must have been the comforting  

 feeling of being close to safety.  This position naturally required  

 a tighter turn and as I turned I saw I was likely to overshoot  the  

 runway and land in the grass. So I though I need to steepen this  

 turn further (Yep!  COFFIN CORNER was calling), but fortunately  

 glanced at my airspeed indicator - to see it only registering 80 MPH  

 and my rate of descent (normally 400-500 feet per minute) up to over  

 1000 feet per minute. The seat cushion suddenly vanished from this  

 universe.



   But the REAL danger in this situation, as you all know, is your  

 airspeed gets low, you are in a steep bank which greatly raises the  

 stall speed  - meaning at 80 mph you are close to a stall in a steep  

 turn while your are not in straight and level.  So I immediately  

 straighten out of the turn – the little voice saying “better to land  

 in the grass than get their concrete runway all messed up”.  So the  

 immediate danger of a stall was adverted, but I was still pointed  

 toward the ground with a sink rate twice as high as normal (and I’ve  

 manage a few hard landings even with a normal sink rate).   

 Fortunately, the runway was now under my nose rather than grass.



 The hardest thing to do when you are sinking at a 1000 fpm a couple  

 hundred feet above the ground (with your nose already pointed at the  

 ground) is to push the stick forward steeping the dive even more.   

 But, I manage to do that and picked enough air speed and energy to  

 flair to a nice touch down – not even a bump.  I’ve always been  

 amazed at what total concentration does to improve you landing {:>).



 Rolled to the end of the runway and had energy to roll off onto the  

 taxiway.   Got out, check under the aircraft for any evidence of  

 leaks and started pulling the aircraft toward the far –off – hangar  

 which had an airplane parked in front of it.  A nice looking young  

 woman comes riding a bicycle out to meet me.  Hopped off and holding  

 out her hand said “Hi I’m Angie, looks like we’ll be spending time  

 together” – so things were starting to look up {:>)



 So pulled the aircraft in to the hangar where the mechanic came over  

 and ask what the problem was.  Well, I looked at the volt meter and  

 it said the battery was dead. Mechanic put on a battery charger and  

 announced “Yep! The battery is dead”.  So we both concluded that the  

 alternator must have failed and not being able to replenish the  

 drain on the battery by all the electrical systems such as fuel  

 pumps, injectors, ignition coils, etc had drained the battery.



 However, there were a few problems with the analysis of a failed  

 alternator.  First, the low voltage warning light never came on to  

 warn of an alternator problem, 2nd I never notice the voltmeter  

 showing anything other than what it should for alternator voltage –  

 like around 14 volts.  While checking the voltage after the Mechanic  

 had charged the battery, I noticed down below that the “essential  

 bus” switch was in the battery rather than the alternator position,  

 so flicked it back to the alternator position figuring I must have  

 accidentally kicked it while getting to some stuff in the baggage  

 compartment of my RV-6A.



 It was getting late and being a bit tired not to mention stressed, I  

 needed to get a rental car and a motel for the night.  Did that, eat  

 dinner and went to bed after sitting down and drawing out a problem  

 tree with the entire major elements of the electrical system.



 So next morning I show up at the hangar early and met Ben, the  

 mechanic, the battery had received a charge of only 45 minutes the  

 evening before, So I suggested we charged it for another hour and  

 try to start the aircraft.  Ben suggested a real stress test of the  

 battery and NOT charge it anymore.  Made sense, so we rolled the  

 aircraft out of the hangar.  I hopped in, threw a half dozen  

 switches and punched the starter button.  The engine started on the  

 first prop blade rotation – so the battery was clearly OK. The  

 engine is humming like a top.    So I looked over at the voltmeter  

 expecting it to show only around 12.8 volts instead of the 14 volts  

 a functioning alternator would produce.  Much to both  my and Ben’s  

 surprise the alternator voltage read 14 volts.  We loaded the  

 alternator by turning on the both l00 watt landing lights, all fuel  

 pumps, the pitot heat, etc.  The alternator voltage only drops  

 perhaps 0.4 volts clearly indicating the alternator could carry the  

 load and was OK.



 So here I am – battery is OK, alternator is OK – engine is purring  

 normally, so clearly this was all a figment of my deteriorating  

 brain cells.  I loaded up the aircraft and launched to do a few  

 circuits of the airport – I did so and all was operating normally  

 and so I radio them I was head onward to Texas.  While flying (with  

 my only functional eyeball on the voltmeter), my mind could not let  

 go of the problem and finally the light bulb came on.



 The essential bus switch had (for my entire 10 + years of  

 flying)always been in the alternator position.  The purpose of this  

 switch is, of course,  to isolate the battery from the alternator  

 should the alternator fail - to prevent an alternator problem from  

 draining the battery.  So in event of an alternator problem, you  

 move the switch from alternator to battery.  Its call the essential  

 bus because you only have the essential things drawing from the  

 battery so you wont’ drain it as quickly.  The idea is to give you  

 time (generally around 30 minutes) to find a safe place to land in  

 case of alternator failure.

 Well, at some point I had either (not paying attention) turned the  

 switch to battery thinking I was turning the voltmeter switch to  

 battery(more on that below)  - or accidentally had move the switch  

 from alternator to battery without noticing it by kicking it, etc.   

 However, it was sort of protected in its position from accidental  

 activation. It must have happened during refueling – as I got approx  

 45 minutes down the road on the battery after take off before  

 quality battery time started to deteriorate.  As the battery voltage  

 fell due to the load (and no alternator link to replenish it),  

 electrical things (mainly computers first) started acting up until  

 they could not longer run the engine. The injectors would not open  

 fully, etc.  Then as the voltage level further decreased, the master  

 relay which the battery held closed and which connected the (fully  

 functional) alternator to the rest of the electrical system - opened  

 up and removed ALL power from the electrical system.  So no radio,  

 no gauges, etc.



  Oh, another little factor that may have contributed, the voltmeter  

 has a tiny toggle switch by it marked ALT BAT1 BAT2 for checking  

 alternator battery 1 and battery 2 (which I no longer fly with)  

 voltages.  Down below It a couple of inches and off to the right is  

 the essential bus normal size toggle switch – also marked ALT BAT1  

 BAT1.  I normally never touch it and don’t even think about it.  But  

 I could have reached for the voltmeter toggle thinking to check my  

 battery voltage (which I do as a regular thing) and perhaps  

 distracted by something reached a bit further down and instead moved  

 the essential bus switch from Alternator to Battery causing this  

 entire event.  I know that I did not consciously do it.  So it is  

 either accidental or absence minded activation - either way ends  

 with the same results {:>)

 Now it became clear why it didn’t matter which pair of fuel  

 injectors I turned off – turning off either pair improved the  

 situation because it slightly reduced the electrical load by a few  

 amps – and the engine ran slightly better for a few moments.  The  

 same thing had happened when turning off one of the EFI fuel pumps –  

 but what threw me was the alternator voltage continued to be normal  

 during this.



 After I knew the cause (switch in wrong position), I decided the  

 problem was fixed so no reason to return to NC, and I just continued  

 on to Texas.



 I know some of you may think that removing my second battery was a  

 mistake – but, consider this, having another battery could have  

 meant I would have been much further from a suitable airfield before  

 they both went south.  On the other hand, it might have caused me to  

 at least think to throw the essential bus switch to the second  

 battery and have the Light bulb come on.  Who really knows.  But, I  

 have in mind a simply addition to my electrical circuit that should  

 help in the future.

 I do want to state that this time when the problems started I DID  

 switch fuel tanks – but naturally it had no effect because this time  

 it turned out, it was not a fuel problem – not the root cause at  

 least.



 So what are the lessons learned:



 	• Put EVERY critical switch on your before-takeoff Check list

 	• Perhaps put a guard around such critical switches to force  

 conscious activation

 	• Don’t (hard not to) get overly focused on what you think is the  

 problem – consider other possibilities.  I thought it was a fuel  

 problem (I even switched fuel tanks this time) – it turned out to be  

 electrical in its root cause.

 	• While the fuel pressure was jumping all over the place and the  

 EGT was erratic and engine surging strongly indicating a fuel  

 problem – the ultimate cause was electrical.  Once the voltage got  

 below a certain point the EC2 computer  was still trying to pull the  

 injectors open, but with the voltage so low it could not do it  

 properly.

 	• When the battery voltage dropped below a certain point, the  

 master relay released and removed the alternator from the electrical  

 system and the panel went dark – even though the alternator was  

 still working

 	• Immediately turn to the nearest airfield when serious problems  

 occur - THEN work on fixing them.  I only delayed for perhaps 2-3  

 minutes, but that could have made a difference.

 	• Watch out for Coffin Corner turn when turning base to final –  

 airspeed really bleeds off fast with no engine pulling you along  

 (and especially with flaps deployed!)

 	• IF you change your mind about landing approach type - remember to  

 reconfigure your aircraft for the last decision – I had left my  

 flaps deployed when I should have remembered to retracted them.  Did  

 that help prevent a Coffin Corner stall and spin or would it have  

 put me closer to it?

 	• You must increase airspeed over the wing to get the sufficient  

 energy to over come a high sink rate.  Pulling back on the stick  

 when the ground is staring you in the face is the natural reaction –  

 but, pushing forward to lower the nose is the correct action –  

 providing of course you have sufficient altitude!

 	• Battery life – I had a two year old 680 odyssey battery which I  

 maintain a trickle charge on whenever I’m not flying.  With two EFI  

 fuel pumps, boost pump, injectors, coils, EC2 and radio and just  

 having started the engine before take off – this battery lasted 55  

 minutes.  Well, the last 5 minutes were not quality battery time.   

 So in my case, 30 minutes appears to be a very realistic battery  

 life.  In fact, had I turned off one EFI pump and the boost pump  

 would have gained a few more miles.  But, if I had recognized the  

 need to turn them off at that time (I normally turn them off at  

 cruise altitude), then I would have known how to “fix” the problem.

 	• I’ve decided to add a Schokkty diode between my essential bus and  

 the alternator – so that as long as the alternator is producing  

 sufficient voltage, then the battery will be getting some charge to  

 replace the drain.  I’ve also decided to make that switch position a  

 check-list item.



  So what it boils down to – if I had recognized early on that it was  

 an electrical problem and not focused so much on the fuel system, I  

 may have noticed the essential bus switch in the wrong position.   

 Force yourself to examine other possible causes (easy to say –  

 harder to do).



 NEVER, NEVER forget that flying the airplane is the first and only  

 priority in this type of situation



 NEVER, NEVER forget that saving your butt is the ultimately end-all  

 priority.  When I decided that landing on the grass was preferable  

 to putting a hole in their concrete – I  may have made a life-saving  

 decision.



 So that’s my story and I’m sticking to it.



 Fly safe, guys!!



 Ed

 Ed Anderson

Ed Anderson

Joined: 10 Jan 2006
Posts: 475

Posted: Wed Jun 03, 2009 4:43 pm Post subject: Essential Incident - Almost (Long)

Sam, its just about on the centerline of the panel but down on the bottom.  So its actually outside my line of vision looking straight ahead.  My voltmeter and its toggle selector is above it approx 3-4” and slightly to the left of it.  Both are within reach without stretching.  

   

As I mentioned the essential bus switch has been in the alternator position for the past 10 years of flying and never moved since initial testing back then.  Should have had it on my pre-takeoff check list and will.  

   

Ed  

     

Ed Anderson  

Rv-6A N494BW Rotary Powered  

Matthews, NC  

eanderson(at)carolina.rr.com  

http://www.andersonee.com  

http://www.dmack.net/mazda/index.html  

http://www.flyrotary.com/  

http://members.cox.net/rogersda/rotary/configs.htm#N494BW  

http://www.rotaryaviation.com/Rotorhead%20Truth.htm[/url]  

        

  

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Sam Hoskins

 Sent: Wednesday, June 03, 2009 4:12 PM

 To: aeroelectric-list(at)matronics.com

 Subject: Re: AeroElectric-List: Essential Incident - Almost (Long)  

  

   

Ed - great story.  Just out of curiosity, where is the essential bus switch located?  Is it plainly in your field of vision or do you have to turn your head to see it?

 

 Cockpit ergonomics are a huge challenge.

 

 Sam Hoskins

 [url=http://www.samhoskins.blogspot.com]www.samhoskins.blogspot.com  

     

On Wed, Jun 3, 2009 at 2:53 PM, Ed Anderson <eanderson(at)carolina.rr.com (eanderson(at)carolina.rr.com)> wrote:      

It was suggested by one of the aeroelectric list members, Sam Hoskins,  that the following report of an incident I had on a recent trip be posted to the AeroElectric list for obvious reasons – once you read it.   

   

 I have an all-electric Rv-6A with over 10 years and close to 500 hours on it.  I based the electrical system roughly one of Bob’s excellent designs.   It initially had one alternator and two batteries, but removed the second battery approx 5 years ago – but, I did make one modification to the  design that I almost had cause to regret.  

   

 So needless to say, but I will,  responsibility for design and incident is  totally mine.   

   

But, to get on with the tale  

   

   

One the way to Texas I had an incident that ended up in with me and aircraft making a 7 mile engine-out glide into Craig Field (Selma,  Alabama).  NO!  It was not fault of the engine or even the subsystems.  But, the complete answer is not provided until after my litany of the conditions and symptoms – can you figure it out?  

   

I took off on Thursday (28 May 2009) AM from North Carolina planning on stopping in Mississippi to join up with two friends.  After spending the night there, we all three would then head for Texas.  But, the weather (as you are aware) has been laying over the southeast for days with rain and more rain – but I launched into it anyway as past Atlanta, GA things were forecast to improve..  

   

Other than dodging lines of clouds and a bit of scud running, but not much, I landed at Alexandria City to the southwest of Atlanta, GA to take on fuel.  I then climbed back in and fire it up and took off.    

   

I noticed that during climb-out the engine would occasionally miss and thought the fuel might have had a bit of water in it, but was not really concerned.  So I fly on for approx another 45 minutes and had just passed Selma, Alabama and old Craig Air Force base, and turned west toward Mississippi, when more symptoms began to occur.  

   

It started to act like a case of SAG (fouled spark plugs) where the rpm will drop a bit – not dangerous - just nerve racking.  But, shortly things began to go beyond the SAG symptoms, so I though I might have an injector problem (like one sticking open or not opening at all).  Since our injectors are in pairs, I tried turning one pair off  figuring if things got better, then that pair might have a bad injector.  

   

So I turned off one pair and sure enough the symptoms abated a bit (more on this later) so I figured I had a bad injector in that pair.  To be certain I turned this “bad” pair back on and turn off the “good” pair expecting the symptoms to really get bad as I would now be running on only the “bad” pair – much to my surprise when I turned off the “good” pair – the symptoms also abated.  So that indicated it was not an injector problem – but what?    

   

About this time, I decided to turn the aircraft back around toward Craig Field and dodging clouds headed back with the engine progressively getting worst. It appeared to be a fuel problem (and while that is ultimately the subsystem affected - it was not the root cause).  The fuel pressure was ranging from zero to 80 psi, other electrical things were also misbehaving.  I check the voltmeter thinking perhaps the alternator had died – but it showed 14 volts.  So back to the fuel system.  

   

  Finally, the engine just stops with the prop standing still - like a hood ornament, I’m at around 4500-5000 MSL at this point having lost some altitude dodging a cloud (good old GPS just kept pointing to Craig Field).  At that time I am 6-7 miles out from Craig Field at 4500 msl with a stopped prop, a crippled seat cushion and a dry mouth.  Yes, I’ve been there before, but I don’t think you ever get “use” to it.  I recalled thinking –“… things just can’t get worst…”   when they very shortly and suddenly - did.  

   

I keyed the radio and made a call to Craig Field at 4 miles on the GPS but before I could get their reply, I heard a “CLANK” (without the engine running you can hear things like that)  like a relay springing open (it was) and the entire panel goes dead!!!!   No radio, no engine instruments, not even a stinking LED was lit – only the battery powered GPS.  Can you spell “total electrical failure?”  Talk about a lonely feeling – amazing how comforting having lights on and radio – you could almost convince yourself this was just a practice engine-out landing, but not when the panel goes dark. No engine gauges, no radio, nada!  

   

Well not being one inclined to panic (but I seriously considered it for a moment {:>)), I continued toward Craig field – I mean like there were lots of other alternatives.  Well Once again I found myself in the “fortunate position” of being too high, too much altitude. So I put in 40 degs of flaps to steepen my rate of descent. But, then I decided this time that rather than do the 360 I had done on a previous Incident to lose “excessive” altitude, I would try to glide - a more or less - regular traffic pattern.  

   

However, I neglected to remember to retract the flaps.  So I found myself on the downwind around mid-field at pattern altitude (which felt normal) until I suddenly realized that you CAN NOT maintain that pattern altitude without an engine!!!  (and particularly with 40 deg of flaps deployed – flaps and trim are manual) Duh!  

   

I knew I could never make it to the far end of the runway before turning base (toward the runway) and I was losing altitude at the rate of 400-500 fpm, so I started my turn immediately.   To make matters a bit worst - I had been paralleling the runway on the downwind leg a bit too close in – must have been the comforting feeling of being close to safety.  This position naturally required a tighter turn and as I turned I saw I was likely to overshoot  the runway and land in the grass. So I though I need to steepen this turn further (Yep!  COFFIN CORNER was calling), but fortunately glanced at my airspeed indicator - to see it only registering 80 MPH and my rate of descent (normally 400-500 feet per minute) up to over 1000 feet per minute. The seat cushion suddenly vanished from this universe.  

   

  But the REAL danger in this situation, as you all know, is your airspeed gets low, you are in a steep bank which greatly raises the stall speed  - meaning at 80 mph you are close to a stall in a steep turn while your are not in straight and level.  So I immediately straighten out of the turn – the little voice saying “better to land in the grass than get their concrete runway all messed up”.  So the immediate danger of a stall was adverted, but I was still pointed toward the ground with a sink rate twice as high as normal (and I’ve manage a few hard landings even with a normal sink rate).  Fortunately, the runway was now under my nose rather than grass.  

   

The hardest thing to do when you are sinking at a 1000 fpm a couple hundred feet above the ground (with your nose already pointed at the ground) is to push the stick forward steeping the dive even more.  But, I manage to do that and picked enough air speed and energy to flair to a nice touch down – not even a bump.  I’ve always been amazed at what total concentration does to improve you landing {:>).  

   

Rolled to the end of the runway and had energy to roll off onto the taxiway.   Got out, check under the aircraft for any evidence of leaks and started pulling the aircraft toward the far –off – hangar which had an airplane parked in front of it.  A nice looking young woman comes riding a bicycle out to meet me.  Hopped off and holding out her hand said “Hi I’m Angie, looks like we’ll be spending time together” – so things were starting to look up {:>)  

   

So pulled the aircraft in to the hangar where the mechanic came over and ask what the problem was.  Well, I looked at the volt meter and it said the battery was dead. Mechanic put on a battery charger and announced “Yep! The battery is dead”.  So we both concluded that the alternator must have failed and not being able to replenish the drain on the battery by all the electrical systems such as fuel pumps, injectors, ignition coils, etc had drained the battery.    

   

However, there were a few problems with the analysis of a failed alternator.  First, the low voltage warning light never came on to warn of an alternator problem, 2nd I never notice the voltmeter showing anything other than what it should for alternator voltage – like around 14 volts.  While checking the voltage after the Mechanic had charged the battery, I noticed down below that the “essential bus” switch was in the battery rather than the alternator position, so flicked it back to the alternator position figuring I must have accidentally kicked it while getting to some stuff in the baggage compartment of my RV-6A.  

   

It was getting late and being a bit tired not to mention stressed, I needed to get a rental car and a motel for the night.  Did that, eat dinner and went to bed after sitting down and drawing out a problem tree with the entire major elements of the electrical system.  

   

So next morning I show up at the hangar early and met Ben, the mechanic, the battery had received a charge of only 45 minutes the evening before, So I suggested we charged it for another hour and try to start the aircraft.  Ben suggested a real stress test of the battery and NOT charge it anymore.  Made sense, so we rolled the aircraft out of the hangar.  I hopped in, threw a half dozen switches and punched the starter button.  The engine started on the first prop blade rotation – so the battery was clearly OK. The engine is humming like a top.    So I looked over at the voltmeter expecting it to show only around 12.8 volts instead of the 14 volts a functioning alternator would produce.  Much to both  my and Ben’s surprise the alternator voltage read 14 volts.  We loaded the alternator by turning on the both l00 watt landing lights, all fuel pumps, the pitot heat, etc.  The alternator voltage only drops perhaps 0.4 volts clearly indicating the alternator could carry the load and was OK.  

   

So here I am – battery is OK, alternator is OK – engine is purring normally, so clearly this was all a figment of my deteriorating brain cells.  I loaded up the aircraft and launched to do a few circuits of the airport – I did so and all was operating normally and so I radio them I was head onward to Texas.  While flying (with my only functional eyeball on the voltmeter), my mind could not let go of the problem and finally the light bulb came on.    

   

The essential bus switch had (for my entire 10 + years of flying)always been in the alternator position.  The purpose of this switch is, of course,  to isolate the battery from the alternator should the alternator fail - to prevent an alternator problem from draining the battery.  So in event of an alternator problem, you move the switch from alternator to battery.  Its call the essential bus because you only have the essential things drawing from the battery so you wont’ drain it as quickly.  The idea is to give you time (generally around 30 minutes) to find a safe place to land in case of alternator failure.  

   

   

Well, at some point I had either (not paying attention) turned the switch to battery thinking I was turning the voltmeter switch to battery(more on that below)  - or accidentally had move the switch from alternator to battery without noticing it by kicking it, etc.  However, it was sort of protected in its position from accidental activation. It must have happened during refueling – as I got approx 45 minutes down the road on the battery after take off before quality battery time started to deteriorate.  As the battery voltage fell due to the load (and no alternator link to replenish it), electrical things (mainly computers first) started acting up until they could not longer run the engine. The injectors would not open fully, etc.  Then as the voltage level further decreased, the master relay which the battery held closed and which connected the (fully functional) alternator to the rest of the electrical system - opened up and removed ALL power from the electrical system.  So no radio, no gauges, etc.   

   

 Oh, another little factor that may have contributed, the voltmeter has a tiny toggle switch by it marked ALT BAT1 BAT2 for checking alternator battery 1 and battery 2 (which I no longer fly with) voltages.  Down below It a couple of inches and off to the right is the essential bus normal size toggle switch – also marked ALT BAT1 BAT1.  I normally never touch it and don’t even think about it.  But I could have reached for the voltmeter toggle thinking to check my battery voltage (which I do as a regular thing) and perhaps distracted by something reached a bit further down and instead moved the essential bus switch from Alternator to Battery causing this entire event.  I know that I did not consciously do it.  So it is either accidental or absence minded activation - either way ends with the same results {:>)  

   

   

Now it became clear why it didn’t matter which pair of fuel injectors I turned off – turning off either pair improved the situation because it slightly reduced the electrical load by a few amps – and the engine ran slightly better for a few moments.  The same thing had happened when turning off one of the EFI fuel pumps – but what threw me was the alternator voltage continued to be normal during this.  

   

After I knew the cause (switch in wrong position), I decided the problem was fixed so no reason to return to NC, and I just continued on to Texas.  

   

I know some of you may think that removing my second battery was a mistake – but, consider this, having another battery could have meant I would have been much further from a suitable airfield before they both went south.  On the other hand, it might have caused me to at least think to throw the essential bus switch to the second battery and have the Light bulb come on.  Who really knows.  But, I have in mind a simply addition to my electrical circuit that should help in the future.   

   

   

I do want to state that this time when the problems started I DID switch fuel tanks – but naturally it had no effect because this time it turned out, it was not a fuel problem – not the root cause at least.  

   

So what are the lessons learned:  

     Put EVERY critical switch on      your before-takeoff Check list   
Perhaps put a guard around such      critical switches to force conscious activation   
Don’t (hard not to) get overly      focused on what you think is the problem – consider other      possibilities.  I thought it was a fuel problem (I even switched fuel      tanks this time) – it turned out to be electrical in its root cause.        
While the fuel pressure was      jumping all over the place and the EGT was erratic and engine surging      strongly indicating a fuel problem – the ultimate cause was      electrical.  Once the voltage got below a certain point the EC2      computer  was still trying to pull the injectors open, but with the      voltage so low it could not do it properly.   
When the battery voltage      dropped below a certain point, the master relay released and removed the      alternator from the electrical system and the panel went dark – even      though the alternator was still working   
Immediately turn to the nearest      airfield when serious problems occur - THEN work on fixing them.  I      only delayed for perhaps 2-3 minutes, but that could have made a      difference.   
Watch out for Coffin Corner turn when turning base      to final – airspeed really bleeds off fast with no engine pulling you      along (and especially with flaps deployed!)   
IF you change your mind about      landing approach type - remember to reconfigure your aircraft for the last      decision – I had left my flaps deployed when I should have remembered to      retracted them.  Did that help prevent a Coffin Corner stall and spin      or would it have put me closer to it?   
You must increase airspeed over      the wing to get the sufficient energy to over come a high sink rate.       Pulling back on the stick when the ground is staring you in the face is      the natural reaction – but, pushing forward to lower the nose is the      correct action – providing of course you have sufficient altitude!        
Battery life –      I had a two year old 680 odyssey battery which I maintain a trickle charge      on whenever I’m not flying.  With two EFI fuel pumps, boost pump,      injectors, coils, EC2 and radio and just having started the engine before      take off – this battery lasted 55 minutes.  Well, the last 5 minutes      were not quality battery time.  So in my case, 30 minutes appears to      be a very realistic battery life.  In fact, had I turned off one EFI      pump and the boost pump would have gained a few more miles.  But, if      I had recognized the need to turn them off at that time (I normally turn      them off at cruise altitude), then I would have known how to “fix” the      problem.   
I’ve decided to add a Schokkty      diode between my essential bus and the alternator – so that as long as the      alternator is producing sufficient voltage, then the battery will be      getting some charge to replace the drain.  I’ve also decided to make      that switch position a check-list item.    

   

 So what it boils down to – if I had recognized early on that it was an electrical problem and not focused so much on the fuel system, I may have noticed the essential bus switch in the wrong position.  Force yourself to examine other possible causes (easy to say – harder to do).   

   

NEVER, NEVER forget that flying the airplane is the first and only priority in this type of situation  

   

NEVER, NEVER forget that saving your butt is the ultimately end-all priority.  When I decided that landing on the grass was preferable to putting a hole in their concrete – I  may have made a life-saving decision.  

   

So that’s my story and I’m sticking to it.    

   

Fly safe, guys!!  

   

Ed  

Ed Anderson  

Rv-6A N494BW Rotary Powered  

Matthews, NC  

eanderson(at)carolina.rr.com (eanderson(at)carolina.rr.com)  

http://www.andersonee.com  

http://www.dmack.net/mazda/index.html  

http://www.flyrotary.com/  

http://members.cox.net/rogersda/rotary/configs.htm#N494BW  

[url=http://www.dmack.net/mazda/index.html][/url]  

   

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_________________
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com

Ed Anderson

Joined: 10 Jan 2006
Posts: 475

Posted: Wed Jun 03, 2009 4:43 pm Post subject: Essential Incident - Almost (Long)

Thanks, Matt



Ed Anderson



Rv-6A N494BW Rotary Powered



Matthews, NC



eanderson(at)carolina.rr.com



http://www.andersonee.com



http://www.dmack.net/mazda/index.html



http://www.flyrotary.com/



http://members.cox.net/rogersda/rotary/configs.htm#N494BW



http://www.rotaryaviation.com/Rotorhead%20Truth.htm

--

_________________
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com

Ed Anderson

Joined: 10 Jan 2006
Posts: 475

Posted: Wed Jun 03, 2009 4:52 pm Post subject: Essential Incident - Almost (Long)

Thanks Kevin



Could not agree with your points more.  Yes, I have a pre-takeoff check list

which I do use - however, as you point out - if an item is not on it that is

critical to safe flight, then it is certainly incomplete.



I do not have an in-flight emergency check list, but will certainly give

that some serious thought - it would be helpful if it just isolated whether

the problem was the fuel system, electrical system and their subsystems.

Another good suggestion



Ah, good analysis, Kevin. You are correct, my low voltage light is hooked to

my alternator circuit and not the essential bus.  The logic (if there was

any) was that if the alternator started to fail then the warning light would

warn me before I started to drain the battery.  However, in this case, the

alternator was continuing to produce 14 V so naturally the low voltage light

never came on.  So again, I agree on all the points you made.



Just goes to show you how even things designed to make it safer can do the

opposite under certain conditions.  Clearly, there are a few things that I

need to change {:>)



Ed  



Ed Anderson



Rv-6A N494BW Rotary Powered



Matthews, NC



eanderson(at)carolina.rr.com



http://www.andersonee.com



http://www.dmack.net/mazda/index.html



http://www.flyrotary.com/



http://members.cox.net/rogersda/rotary/configs.htm#N494BW



http://www.rotaryaviation.com/Rotorhead%20Truth.htm

--

_________________
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com

Bill Schlatterer

Joined: 09 Jan 2006
Posts: 195

Posted: Wed Jun 03, 2009 6:02 pm Post subject: Essential Incident - Almost (Long)

Ed, just curious,... How is it that your essential switch disconnects the

main bus?  Usually, they power the essential bus but you have to shut off

the Main bus (I think) manually as a safety feature.  When you heard the

CLANK which you said was the main bus relay disconnecting, that would have

been caused by the absolute drain of the battery.  BUT, with the master

relay still engaged, the alternator should have still been charging the

battery? (even with the E-Bus switch thrown,... I think?



If your essential completely reroutes the current from the alternator around

the battery, then what takes up the load with the single battery off line?

Is that what the second battery (removed) was supposed to do?



Just wondering how it works?



Thanks Bill S

7a finishing / Z13/8 and other stuff



--

etienne.phillips(at)gmail
Guest

Posted: Wed Jun 03, 2009 9:57 pm Post subject: Essential Incident - Almost (Long)

Hi Ed



Aren't you glad you weren't flying at night! 



A diagram of your electrical system as it was would help us understand what you did, and why its design caused the failure... Of particular interest is why switching on the e-bus disconnected the alternator. I also can't seem to make out why when the main bus still had power from the alternator, the contactor died when the e-bus voltage dropped. It may prompt Bob to suggest a better solution to what you're planning  

Not pointing fingers here, I just can't visualise how it's all hooked up!

Thanks

Etienne



On 03 Jun 2009, at 9:53 PM, Ed Anderson wrote:

[quote]It was suggested by one of the aeroelectric list members, Sam Hoskins,  that the following report of an incident I had on a recent trip be posted to the AeroElectric list for obvious reasons – once you read it.

 

 I have an all-electric Rv-6A with over 10 years and close to 500 hours on it.  I based the electrical system roughly one of Bob’s excellent designs.   It initially had one alternator and two batteries, but removed the second battery approx 5 years ago – but, I did make one modification to the  design that I almost had cause to regret.

 

 So needless to say, but I will,  responsibility for design and incident is  totally mine.

 

But, to get on with the tale

 

 

One the way to Texas I had an incident that ended up in with me and aircraft making a 7 mile engine-out glide into Craig Field (Selma, Alabama).  NO!  It was not fault of the engine or even the subsystems.  But, the complete answer is not provided until after my litany of the conditions and symptoms – can you figure it out?

 

 

Fly safe, guys!!

 

Ed



[b]

kahuna

Joined: 02 Feb 2007
Posts: 93

Posted: Thu Jun 04, 2009 4:20 am Post subject: Essential Incident - Almost (Long)

Great Great story Ed. Thank you for sharing.

 

 On the checklist thing, One thing I did was start with the premise that any idiot should be able to jump in my airplane and fly it. This can be a tall order as some of my flying buddies are even bigger idiots than me.

 

 To test my check lists, I let several pilots jump in my plane and take it for a ride. Needless to say, my check list, and cockpit nomenclature, went through quite a few additions, and very good ones. From the moment they climb in, their faces contort and they fish and find, asking questions that pointed to issues. In the heat of battle, you dont want to have to remember how things/systems work, this switch to that positions for this thing to happen etc.. Trying to make the activities idiot proof is important to me, cause I can turn into a real idiot often, especially when things go awry, my idiot factor increases dramatically. I have had many opportunities to prove this to myself over my thousands of RV flying hours. 

 

 While this technique may not have identified this item, it might identify others. Every question from another pilot who has to get in it and get air born, means some complexity or area of confusion that is a candidate for addressing. 

 

 Also since I rely on my electrical system heavily(too much gee whiz stuff), when Im zipping along from A to B, I fail things just to verify expected behavior. Usually its just entertainment for me on my cross countries, but mostly is verifies the fail overs work as designed. Thinking of failure modes can occupy those mundane cross countries as well.

 

 Just a few thoughts for you and thanks for the great write up Ed.

 Best,

 Mike

 

 

 

 [img]cid:1__=08BBFF58DFD2D63A8f9e8a93df938(at)us.ibm.com[/img]"Ed Anderson" ---06/03/2009 04:30:14 PM---It was suggested by one of the aeroelectric list members, Sam Hoskins,  that the following report of

 

   [img]cid:2__=08BBFF58DFD2D63A8f9e8a93df938(at)us.ibm.com[/img]

 From:[img]cid:2__=08BBFF58DFD2D63A8f9e8a93df938(at)us.ibm.com[/img]

 "Ed Anderson" <eanderson(at)carolina.rr.com>  [img]cid:2__=08BBFF58DFD2D63A8f9e8a93df938(at)us.ibm.com[/img]

 To:[img]cid:2__=08BBFF58DFD2D63A8f9e8a93df938(at)us.ibm.com[/img]

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 Date:[img]cid:2__=08BBFF58DFD2D63A8f9e8a93df938(at)us.ibm.com[/img]

 06/03/2009 04:30 PM  [img]cid:2__=08BBFF58DFD2D63A8f9e8a93df938(at)us.ibm.com[/img]

 Subject:[img]cid:2__=08BBFF58DFD2D63A8f9e8a93df938(at)us.ibm.com[/img]

 AeroElectric-List: Essential Incident - Almost (Long)  [img]cid:2__=08BBFF58DFD2D63A8f9e8a93df938(at)us.ibm.com[/img]

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 owner-aeroelectric-list-server(at)matronics.com  

 

 

 It was suggested by one of the aeroelectric list members, Sam Hoskins,  that the following report of an incident I had on a recent trip be posted to the AeroElectric list for obvious reasons â€“ once you read it. 

  

  I have an all-electric Rv-6A with over 10 years and close to 500 hours on it.  I based the electrical system roughly one of Bobâ€™s excellent designs.   It initially had one alternator and two batteries, but removed the second battery approx 5 years ago â€“ but, I did make one modification to the  design that I almost had cause to regret.

  

  So needless to say, but I will,  responsibility for design and incident is  totally mine. 

  

 But, to get on with the tale

  

  

 One the way to Texas I had an incident that ended up in with me and aircraft making a 7 mile engine-out glide into Craig Field (Selma, Alabama).  NO!  It was not fault of the engine or even the subsystems.  But, the complete answer is not provided until after my litany of the conditions and symptoms â€“ can you figure it out?

  

 I took off on Thursday (28 May 2009) AM from North Carolina planning on stopping in Mississippi to join up with two friends.  After spending the night there, we all three would then head for Texas.  But, the weather (as you are aware) has been laying over the southeast for days with rain and more rain â€“ but I launched into it anyway as past Atlanta, GA things were forecast to improve..

  

 Other than dodging lines of clouds and a bit of scud running, but not much, I landed at Alexandria City to the southwest of Atlanta, GA to take on fuel.  I then climbed back in and fire it up and took off.  

  

 I noticed that during climb-out the engine would occasionally miss and thought the fuel might have had a bit of water in it, but was not really concerned.  So I fly on for approx another 45 minutes and had just passed Selma, Alabama and old Craig Air Force base, and turned west toward Mississippi, when more symptoms began to occur.

  

 It started to act like a case of SAG (fouled spark plugs) where the rpm will drop a bit â€“ not dangerous - just nerve racking.  But, shortly things began to go beyond the SAG symptoms, so I though I might have an injector problem (like one sticking open or not opening at all).  Since our injectors are in pairs, I tried turning one pair off  figuring if things got better, then that pair might have a bad injector.

  

 So I turned off one pair and sure enough the symptoms abated a bit (more on this later) so I figured I had a bad injector in that pair.  To be certain I turned this â€œbadâ€ pair back on and turn off the â€œgoodâ€ pair expecting the symptoms to really get bad as I would now be running on only the â€œbadâ€ pair â€“ much to my surprise when I turned off the â€œgoodâ€ pair â€“ the symptoms also abated.  So that indicated it was not an injector problem â€“ but what?  

  

 About this time, I decided to turn the aircraft back around toward Craig Field and dodging clouds headed back with the engine progressively getting worst. It appeared to be a fuel problem (and while that is ultimately the subsystem affected - it was not the root cause).  The fuel pressure was ranging from zero to 80 psi, other electrical things were also misbehaving.  I check the voltmeter thinking perhaps the alternator had died â€“ but it showed 14 volts.  So back to the fuel system.

  

   Finally, the engine just stops with the prop standing still - like a hood ornament, Iâ€™m at around 4500-5000 MSL at this point having lost some altitude dodging a cloud (good old GPS just kept pointing to Craig Field).  At that time I am 6-7 miles out from Craig Field at 4500 msl with a stopped prop, a crippled seat cushion and a dry mouth.  Yes, Iâ€™ve been there before, but I donâ€™t think you ever get â€œuseâ€ to it.  I recalled thinking â€“â€œâ€¦ things just canâ€™t get worstâ€¦â€   when they very shortly and suddenly - did.

  

 I keyed the radio and made a call to Craig Field at 4 miles on the GPS but before I could get their reply, I heard a â€œCLANKâ€ (without the engine running you can hear things like that)  like a relay springing open (it was) and the entire panel goes dead!!!!   No radio, no engine instruments, not even a stinking LED was lit â€“ only the battery powered GPS.  Can you spell â€œtotal electrical failure?â€  Talk about a lonely feeling â€“ amazing how comforting having lights on and radio â€“ you could almost convince yourself this was just a practice engine-out landing, but not when the panel goes dark. No engine gauges, no radio, nada!

  

 Well not being one inclined to panic (but I seriously considered it for a moment {:>)), I continued toward Craig field â€“ I mean like there were lots of other alternatives.  Well Once again I found myself in the â€œfortunate positionâ€ of being too high, too much altitude. So I put in 40 degs of flaps to steepen my rate of descent. But, then I decided this time that rather than do the 360 I had done on a previous Incident to lose â€œexcessiveâ€ altitude, I would try to glide - a more or less - regular traffic pattern.

  

 However, I neglected to remember to retract the flaps.  So I found myself on the downwind around mid-field at pattern altitude (which felt normal) until I suddenly realized that you CAN NOT maintain that pattern altitude without an engine!!!  (and particularly with 40 deg of flaps deployed â€“ flaps and trim are manual) Duh!

  

 I knew I could never make it to the far end of the runway before turning base (toward the runway) and I was losing altitude at the rate of 400-500 fpm, so I started my turn immediately.   To make matters a bit worst - I had been paralleling the runway on the downwind leg a bit too close in â€“ must have been the comforting feeling of being close to safety.  This position naturally required a tighter turn and as I turned I saw I was likely to overshoot  the runway and land in the grass. So I though I need to steepen this turn further (Yep!  COFFIN CORNER was calling), but fortunately glanced at my airspeed indicator - to see it only registering 80 MPH and my rate of descent (normally 400-500 feet per minute) up to over 1000 feet per minute. The seat cushion suddenly vanished from this universe.

  

   But the REAL danger in this situation, as you all know, is your airspeed gets low, you are in a steep bank which greatly raises the stall speed  - meaning at 80 mph you are close to a stall in a steep turn while your are not in straight and level.  So I immediately straighten out of the turn â€“ the little voice saying â€œbetter to land in the grass than get their concrete runway all messed upâ€.  So the immediate danger of a stall was adverted, but I was still pointed toward the ground with a sink rate twice as high as normal (and Iâ€™ve manage a few hard landings even with a normal sink rate).  Fortunately, the runway was now under my nose rather than grass.

  

 The hardest thing to do when you are sinking at a 1000 fpm a couple hundred feet above the ground (with your nose already pointed at the ground) is to push the stick forward steeping the dive even more.  But, I manage to do that and picked enough air speed and energy to flair to a nice touch down â€“ not even a bump.  Iâ€™ve always been amazed at what total concentration does to improve you landing {:>).

  

 Rolled to the end of the runway and had energy to roll off onto the taxiway.   Got out, check under the aircraft for any evidence of leaks and started pulling the aircraft toward the far â€“off â€“ hangar which had an airplane parked in front of it.  A nice looking young woman comes riding a bicycle out to meet me.  Hopped off and holding out her hand said â€œHi Iâ€™m Angie, looks like weâ€™ll be spending time togetherâ€ â€“ so things were starting to look up {:>)

  

 So pulled the aircraft in to the hangar where the mechanic came over and ask what the problem was.  Well, I looked at the volt meter and it said the battery was dead. Mechanic put on a battery charger and announced â€œYep! The battery is deadâ€.  So we both concluded that the alternator must have failed and not being able to replenish the drain on the battery by all the electrical systems such as fuel pumps, injectors, ignition coils, etc had drained the battery.  

  

 However, there were a few problems with the analysis of a failed alternator.  First, the low voltage warning light never came on to warn of an alternator problem, 2nd I never notice the voltmeter showing anything other than what it should for alternator voltage â€“ like around 14 volts.  While checking the voltage after the Mechanic had charged the battery, I noticed down below that the â€œessential busâ€ switch was in the battery rather than the alternator position, so flicked it back to the alternator position figuring I must have accidentally kicked it while getting to some stuff in the baggage compartment of my RV-6A.

  

 It was getting late and being a bit tired not to mention stressed, I needed to get a rental car and a motel for the night.  Did that, eat dinner and went to bed after sitting down and drawing out a problem tree with the entire major elements of the electrical system.

  

 So next morning I show up at the hangar early and met Ben, the mechanic, the battery had received a charge of only 45 minutes the evening before, So I suggested we charged it for another hour and try to start the aircraft.  Ben suggested a real stress test of the battery and NOT charge it anymore.  Made sense, so we rolled the aircraft out of the hangar.  I hopped in, threw a half dozen switches and punched the starter button.  The engine started on the first prop blade rotation â€“ so the battery was clearly OK. The engine is humming like a top.    So I looked over at the voltmeter expecting it to show only around 12.8 volts instead of the 14 volts a functioning alternator would produce.  Much to both  my and Benâ€™s surprise the alternator voltage read 14 volts.  We loaded the alternator by turning on the both l00 watt landing lights, all fuel pumps, the pitot heat, etc.  The alternator voltage only drops perhaps 0.4 volts clearly indicating the alternator could carry the load and was OK.

  

 So here I am â€“ battery is OK, alternator is OK â€“ engine is purring normally, so clearly this was all a figment of my deteriorating brain cells.  I loaded up the aircraft and launched to do a few circuits of the airport â€“ I did so and all was operating normally and so I radio them I was head onward to Texas.  While flying (with my only functional eyeball on the voltmeter), my mind could not let go of the problem and finally the light bulb came on.  

  

 The essential bus switch had (for my entire 10 + years of flying)always been in the alternator position.  The purpose of this switch is, of course,  to isolate the battery from the alternator should the alternator fail - to prevent an alternator problem from draining the battery.  So in event of an alternator problem, you move the switch from alternator to battery.  Its call the essential bus because you only have the essential things drawing from the battery so you wontâ€™ drain it as quickly.  The idea is to give you time (generally around 30 minutes) to find a safe place to land in case of alternator failure.

  

  

 Well, at some point I had either (not paying attention) turned the switch to battery thinking I was turning the voltmeter switch to battery(more on that below)  - or accidentally had move the switch from alternator to battery without noticing it by kicking it, etc.  However, it was sort of protected in its position from accidental activation. It must have happened during refueling â€“ as I got approx 45 minutes down the road on the battery after take off before quality battery time started to deteriorate.  As the battery voltage fell due to the load (and no alternator link to replenish it), electrical things (mainly computers first) started acting up until they could not longer run the engine. The injectors would not open fully, etc.  Then as the voltage level further decreased, the master relay which the battery held closed and which connected the (fully functional) alternator to the rest of the electrical system - opened up and removed ALL power from the electrical system.  So no radio, no gauges, etc. 

  

  Oh, another little factor that may have contributed, the voltmeter has a tiny toggle switch by it marked ALT BAT1 BAT2 for checking alternator battery 1 and battery 2 (which I no longer fly with) voltages.  Down below It a couple of inches and off to the right is the essential bus normal size toggle switch â€“ also marked ALT BAT1 BAT1.  I normally never touch it and donâ€™t even think about it.  But I could have reached for the voltmeter toggle thinking to check my battery voltage (which I do as a regular thing) and perhaps distracted by something reached a bit further down and instead moved the essential bus switch from Alternator to Battery causing this entire event.  I know that I did not consciously do it.  So it is either accidental or absence minded activation - either way ends with the same results {:>)

  

  

 Now it became clear why it didnâ€™t matter which pair of fuel injectors I turned off â€“ turning off either pair improved the situation because it slightly reduced the electrical load by a few amps â€“ and the engine ran slightly better for a few moments.  The same thing had happened when turning off one of the EFI fuel pumps â€“ but what threw me was the alternator voltage continued to be normal during this.

  

 After I knew the cause (switch in wrong position), I decided the problem was fixed so no reason to return to NC, and I just continued on to Texas.

  

 I know some of you may think that removing my second battery was a mistake â€“ but, consider this, having another battery could have meant I would have been much further from a suitable airfield before they both went south.  On the other hand, it might have caused me to at least think to throw the essential bus switch to the second battery and have the Light bulb come on.  Who really knows.  But, I have in mind a simply addition to my electrical circuit that should help in the future. 

  

  

 I do want to state that this time when the problems started I DID switch fuel tanks â€“ but naturally it had no effect because this time it turned out, it was not a fuel problem â€“ not the root cause at least.

  

 So what are the lessons learned:

   1.	Put EVERY critical switch on your before-takeoff Check list 

 2.	Perhaps put a guard around such critical switches to force conscious activation 

 3.	Donâ€™t (hard not to) get overly focused on what you think is the problem â€“ consider other possibilities.  I thought it was a fuel problem (I even switched fuel tanks this time) â€“ it turned out to be electrical in its root cause. 

 4.	While the fuel pressure was jumping all over the place and the EGT was erratic and engine surging strongly indicating a fuel problem â€“ the ultimate cause was electrical.  Once the voltage got below a certain point the EC2 computer  was still trying to pull the injectors open, but with the voltage so low it could not do it properly. 

 5.	When the battery voltage dropped below a certain point, the master relay released and removed the alternator from the electrical system and the panel went dark â€“ even though the alternator was still working 

 6.	Immediately turn to the nearest airfield when serious problems occur - THEN work on fixing them.  I only delayed for perhaps 2-3 minutes, but that could have made a difference. 

 7.	Watch out for Coffin Corner turn when turning base to final â€“ airspeed really bleeds off fast with no engine pulling you along (and especially with flaps deployed!) 

 8.	IF you change your mind about landing approach type - remember to reconfigure your aircraft for the last decision â€“ I had left my flaps deployed when I should have remembered to retracted them.  Did that help prevent a Coffin Corner stall and spin or would it have put me closer to it? 

 9.	You must increase airspeed over the wing to get the sufficient energy to over come a high sink rate.  Pulling back on the stick when the ground is staring you in the face is the natural reaction â€“ but, pushing forward to lower the nose is the correct action â€“ providing of course you have sufficient altitude! 

 10.	Battery life â€“ I had a two year old 680 odyssey battery which I maintain a trickle charge on whenever Iâ€™m not flying.  With two EFI fuel pumps, boost pump, injectors, coils, EC2 and radio and just having started the engine before take off â€“ this battery lasted 55 minutes.  Well, the last 5 minutes were not quality battery time.  So in my case, 30 minutes appears to be a very realistic battery life.  In fact, had I turned off one EFI pump and the boost pump would have gained a few more miles.  But, if I had recognized the need to turn them off at that time (I normally turn them off at cruise altitude), then I would have known how to â€œfixâ€ the problem. 

 11.	Iâ€™ve decided to add a Schokkty diode between my essential bus and the alternator â€“ so that as long as the alternator is producing sufficient voltage, then the battery will be getting some charge to replace the drain.  Iâ€™ve also decided to make that switch position a check-list item.   

  So what it boils down to â€“ if I had recognized early on that it was an electrical problem and not focused so much on the fuel system, I may have noticed the essential bus switch in the wrong position.  Force yourself to examine other possible causes (easy to say â€“ harder to do). 

  

 NEVER, NEVER forget that flying the airplane is the first and only priority in this type of situation

  

 NEVER, NEVER forget that saving your butt is the ultimately end-all priority.  When I decided that landing on the grass was preferable to putting a hole in their concrete â€“ I  may have made a life-saving decision.

  

 So thatâ€™s my story and Iâ€™m sticking to it.  

  

 Fly safe, guys!!

  

 Ed 

Ed Anderson 

Rv-6A N494BW Rotary Powered 

Matthews, NC 

eanderson(at)carolina.rr.com 

http://www.andersonee.com 

http://www.dmack.net/mazda/index.html 

http://www.flyrotary.com/ 

http://members.cox.net/rogersda/rotary/configs.htm#N494BW 

[url=http://www.dmack.net/mazda/index.html][/url]

   

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Speedy11(at)aol.com
Guest

Posted: Thu Jun 04, 2009 5:11 am Post subject: Essential Incident - Almost (Long)

Ed,

 Great story - thanks for sharing.

 Thanks also for your insight into the problem, analysis, and  solutions.

 Stan Sutterfield

 Limited Time Offers: Save big on popular laptops at Dell

  [quote][b]

Ed Anderson

Joined: 10 Jan 2006
Posts: 475

Posted: Thu Jun 04, 2009 5:24 pm Post subject: Essential Incident - Almost (Long)

Hi Bill,



Perhaps a bit clear explanation of my circuit.  When I move my essential bus

switch from ALT (alternator) to BAT1 (battery1), it removes the link between

battery and alternator.  However, the master relay still closed by the

battery voltage, so this provides a path for the alternator to continue to

feed the rest of the (none essential systems - such as landing lights,

strobe light, transponder, etc).



When the battery voltage dropped  low enough it was unable to hold the

master relay closed - which opened removing alternator voltage from the rest

of the system.  By that time, the battery was too low to support the

essential systems such as my engine and to include the radio.



When the battery is disconnected from the alternator, there is no noticeable

variation in my alternator voltage indicating that the none-essential

subsystems apparently provide sufficient load stability. That's my best

analysis of the system.



Ed



Ed Anderson



Rv-6A N494BW Rotary Powered



Matthews, NC



eanderson(at)carolina.rr.com



http://www.andersonee.com



http://www.dmack.net/mazda/index.html



http://www.flyrotary.com/



http://members.cox.net/rogersda/rotary/configs.htm#N494BW



http://www.rotaryaviation.com/Rotorhead%20Truth.htm



--

_________________
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com

Ed Anderson

Joined: 10 Jan 2006
Posts: 475

Posted: Thu Jun 04, 2009 5:34 pm Post subject: Essential Incident - Almost (Long)

Hi Etienne,  

   

No one can point finger at me better than myself.  As I indicated the modifications to Bob’s excellent design and resulting  incident rest strictly with me – no getting around that (even if I tried).  

   

As best I can recall from over 10 years ago,  I decided I did not want the voltage drop caused by a isolation diode (as you might imagine I am reconsidering that decision).  So when I move my essential bus switch from Alternator to Battery, the battery is completely disconnected from alternator circuit.  At the same time the battery voltage is what is holding my master relay closed so that the alternator feeds the electrical system.  Normally (at least for the past 10 years and 450 + hours) has worked as I had envisioned.  But, never having an alternator failure, I never had reason to move the switch from the Alternator position.  

   

In this case, the switch was moved to battery which isolated the battery from the alternator completely – This was of course unintentional, but all the same resulted in exhaustion of the battery while I still had a perfectly good alternator functioning.  Needless to say, that requires me to reconsider my design.   

   

The simplest fix appears to be  to put the isolation diode between alternator and battery essential bus.   

   

Ed  

     

Ed Anderson  

Rv-6A N494BW Rotary Powered  

Matthews, NC  

eanderson(at)carolina.rr.com  

http://www.andersonee.com  

http://www.dmack.net/mazda/index.html  

http://www.flyrotary.com/  

http://members.cox.net/rogersda/rotary/configs.htm#N494BW  

http://www.rotaryaviation.com/Rotorhead%20Truth.htm[url=http://www.dmack.net/mazda/index.html][/url]  

        

  

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Etienne Phillips

 Sent: Thursday, June 04, 2009 1:55 AM

 To: aeroelectric-list(at)matronics.com

 Subject: Re: AeroElectric-List: Essential Incident - Almost (Long)  

  

   

Hi Ed    

   

    

Aren't you glad you weren't flying at night!     

   

    

A diagram of your electrical system as it was would help us understand what you did, and why its design caused the failure... Of particular interest is why switching on the e-bus disconnected the alternator. I also can't seem to make out why when the main bus still had power from the alternator, the contactor died when the e-bus voltage dropped. It may prompt Bob to suggest a better solution to what you're planning    

    

   

    

Not pointing fingers here, I just can't visualise how it's all hooked up!  

    

   

    

Thanks  

    

Etienne  

    

       

On 03 Jun 2009, at 9:53 PM, Ed Anderson wrote:  

  



 

       

It was suggested by one of the aeroelectric list members, Sam Hoskins,  that the following report of an incident I had on a recent trip be posted to the AeroElectric list for obvious reasons – once you read it.  

    

   

    

 I have an all-electric Rv-6A with over 10 years and close to 500 hours on it.  I based the electrical system roughly one of Bob’s excellent designs.   It initially had one alternator and two batteries, but removed the second battery approx 5 years ago – but, I did make one modification to the  design that I almost had cause to regret.  

    

   

    

 So needless to say, but I will,  responsibility for design and incident is  totally mine.  

    

   

    

But, to get on with the tale  

    

   

    

   

    

One the way to Texas I had an incident that ended up in with me and aircraft making a 7 mile engine-out glide into Craig Field (Selma, Alabama).  NO!  It was not fault of the engine or even the subsystems.  But, the complete answer is not provided until after my litany of the conditions and symptoms – can you figure it out?  

    

   

    

   

    

Fly safe, guys!!  

    

   

    

Ed  

  

  

  

  

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_________________
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com

klehman(at)albedo.net
Guest

Posted: Fri Jun 05, 2009 3:45 am Post subject: Essential Incident - Almost (Long)

A related discussion FWIW:



I still think that the electrically dependent engine and especially with 

internal regulated alternators, may be better served by connecting the 

alternator to the battery side of a battery contactor. Even more so if 

you have a separate OV contactor or if you run small batteries. I've 

done that on both alternators of my Z-14 system. Separate guarded 

switches control the OV contactors.



In a smoke situation I want to kill everything not required by the 

engine but if the smoke stops I still want the option of keeping the 

alternator. I don't want to risk load dumping my internally regulated 

alternator if I don't have to. I run very small 8AH batteries but 

interestingly one of them lost almost all of its capacity very quickly 

last winter. The second one still cranked the engine fairly well so it 

was not obvious. It did not seem to go open circuit as it would still 

supply a 5 amp load for 2 or 3 minutes. De-sulphating pulses made no 

improvement.



My voltmeters and OV sensing are off the battery busses since they run 

the engine.



Ken



Ed Anderson wrote:

 	  Quote: 	
		   

 

 Hi Bill,

 

 Perhaps a bit clear explanation of my circuit.  When I move my essential bus

Lenny Iszak

Joined: 23 Mar 2008
Posts: 270

Posted: Fri Jun 05, 2009 6:45 pm Post subject: Re: Essential Incident - Almost (Long)

Ed,



Wouldn't isolating the battery from the alternator stop the alternator from generating power? Or do you have a permanent magnet alternator?



Or was the alternator originally switched to the auxiliary, now non-existent battery to keep feeding your e-bus?



Lenny

Ed Anderson

Joined: 10 Jan 2006
Posts: 475

Posted: Sat Jun 06, 2009 5:11 am Post subject: Essential Incident - Almost (Long)

Hi Lenny,



I have an auto alternator with internal regulator.  The alternator ONLY

needs battery voltage to get started - once its producing voltage it uses

its own voltage to keep its field coils energized and magnetized.  In fact,

I can pull the alternator field coil circuit breaker once the engine is

running and it has no effect on the alternator.  Yes, you do need the

battery to jump start /bootstrap the alternator to producing voltage. 



Now with the typical aircraft alternator, it's a bit different story.  They

normally have an external regulator which permits you to remove voltage from

the alternator field coil and in this case, if you pull the CB and remove

voltage from the field coil it will stop producing voltage.  But, once again

you only need the battery to get it started.



At least that is my understanding of the major difference between auto and

aircraft alternators.



Ed



Ed Anderson



Rv-6A N494BW Rotary Powered



Matthews, NC



eanderson(at)carolina.rr.com



http://www.andersonee.com



http://www.dmack.net/mazda/index.html



http://www.flyrotary.com/



http://members.cox.net/rogersda/rotary/configs.htm#N494BW



http://www.rotaryaviation.com/Rotorhead%20Truth.htm

--

_________________
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com

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