Matronics Email Lists :: View topic - Need for start-up protection?

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Need for start-up protection?
Goto page 1, 2 Next

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

Sam

Joined: 18 May 2008
Posts: 135

Posted: Mon Dec 08, 2008 7:23 am Post subject: Need for start-up protection?

I know this has been discussed before, but it's hitting a little closer to home, and I thought I'd bring it up again.



While installing my new ICOM IC-A210 com radio I found this little warning block in the pilot's instruction manual:

 "CAUTION:  DO NOT turn the power ON until the aircraft engines have been started.  It is very important for protection of the power supply circuit."



(On the other hand, my Dynon D180 installation manual states several times that it is okay to have the unit on when starting).

 

For other matters of confusion, the ICOM Pilot's manual says "NEVER connect to a power source that is fused at more than 5A".  But the installation instructions say to use 18AWG wire with a 10 A circuit breaker.  The specifications listed on the web site says it uses up to 5A during transmitting.

 

So, how do I make sure the ICOM is always off before engine start?  Or should I not bother?  I have a B&C permenant magnet alternator.

 	  Quote: 	
		  	
Sam Hoskins

www.samhoskins.blogspot.com

  [quote][b]

_________________
Sam Hoskins
www.samhoskins.blogspot.com

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Dec 08, 2008 10:14 am Post subject: Need for start-up protection?

At 09:22 AM 12/8/2008, you wrote:

  	  Quote: 	
		  I know this has been discussed before, but it's hitting a little closer to home, and I thought I'd bring it up again.



 While installing my new  ICOM IC-A210 com radio I found this little warning block in the pilot's instruction manual:

 "CAUTION:  DO NOT turn the power ON until the aircraft engines have been started.  It is very important for protection of the power supply circuit." 	


    I've heard that this radio is at risk for damage to any

    voltages over 16v during an OV condition. There are no

    "spikes" that exceed this value during cranking but if

    the radio was not blessed with design goals conforming

    to DO160 recommendations, perhaps they're admitting

    to a vulnerability that most suppliers to the industry

    choose to live with.



 

  	  Quote: 	
		  (On the other hand, my Dynon D180 installation manual states several times that it is okay to have the unit on when starting). 	


    Yup, they probably did due diligence under the recommendations

    for DO160 compliance.



 

  	  Quote: 	
		  For other matters of confusion, the ICOM Pilot's manual says "NEVER connect to a power source that is fused at more than 5A".  But the installation instructions say to use 18AWG wire with a 10 A circuit breaker.  The specifications listed on the web site says it uses up to 5A during transmitting. 	


   The 5A breaker would be fine. Your transmissions are so

   short and the receive power so low that you're not likely

   to trip a 5A breaker. 



 

  	  Quote: 	
		  So, how do I make sure the ICOM is always off before engine start?  Or should I not bother?  I have a B&C permenant magnet alternator. 	


   Turn it off/on as part of your post/pre-flight checklist.



 

        Bob . . .



        ----------------------------------------)

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

        ----------------------------------------



     [quote][b]

rdunhamtn(at)hotmail.com
Guest

Posted: Mon Dec 08, 2008 11:34 am Post subject: Need for start-up protection?

Sam C



The short 'n sweet answer to...

"So C how do I make sure the ICOM is always off before engine start?"

...is. Reach over and twist the ON/OFF knob CCW until it clicks!



I do the "5 M's" mnoemonic on shutdown to help me remember to switch everything off C including the Master.

...Music (turn off all avionics in addition to radios if needed)

..Mags (quick mag check C just to let you know that the rpm's drop on one mag)

...Mixture (full lean for engine cut-off)

...Mags (both off)

...Master (off)



No fancy electronic knowledge required. Just good airmanship.



Rodney in Tennessee

Date: Mon C 8 Dec 2008 09:22:07 -0600

From: sam.hoskins(at)gmail.com

To: aeroelectric-list(at)matronics.com

Subject: Need for start-up protection?



I know this has been discussed before C but it's hitting a little closer to home C and I thought I'd bring it up again.



While installing my new ICOM IC-A210 com radio I found this little warning block in the pilot's instruction manual:

 "CAUTION:  DO NOT turn the power ON until the aircraft engines have been started.  It is very important for protection of the power supply circuit."



(On the other hand C my Dynon D180 installation manual states several times that it is okay to have the unit on when starting).

 

For other matters of confusion C the ICOM Pilot's manual says "NEVER connect to a power source that is fused at more than 5A".  But the installation instructions say to use 18AWG wire with a 10 A circuit breaker.  The specifications listed on the web site says it uses up to 5A during transmitting.

 

So C how do I make sure the ICOM is always off before engine start?  Or should I not bother?  I have a B&C permenant magnet alternator.

 	  Quote: 	
		  	
Sam Hoskins

www.samhoskins.blogspot.com

   	  Quote: 	
		  http://www.matronics.com/Navigat========= 	
Suspicious message? There’s an alert for that.  Get your Hotmail® account now.  [quote][b]

echristley(at)nc.rr.com
Guest

Posted: Mon Dec 08, 2008 1:16 pm Post subject: Need for start-up protection?

Rodney Dunham wrote:

 	  Quote: 	
		   Sam,



 The short 'n sweet answer to...

 "So, how do I make sure the ICOM is always off before engine start?"

 ...is. Reach over and twist the ON/OFF knob CCW until it clicks!



What if the on/off switch is a push button type?
	


 	  Quote: 	
		   I do the "5 M's" mnoemonic on shutdown to help me remember to switch 

 everything off, including the Master.

 ...Music (turn off all avionics in addition to radios if needed)

 ...Mags (quick mag check, just to let you know that the rpm's drop on 

 one mag)

 ...Mixture (full lean for engine cut-off)

 ...Mags (both off)

 ...Master (off)



 No fancy electronic knowledge required. Just good airmanship.

And there's nothing wrong with good airmanship...however...
	




'Good airmanship' is so often code words for learning another lists of 

mnemonics to overcome the shortfalls of a poor system design.  Why 

should I be forced to turn off so many systems manually before turning 

off a master switch?  I don't have to do that in an automobile.  An 

airplane engine is not that significantly different.  Granted, the 

certificated airplanes are stuck by Federal decree with their glorious 

bobby-sock era glory, but the year is 2008, we're building and 

maintaining our own systems, and we no longer have to suffer such 

idiocy.  The airplane should be built to accommodate the pilot, not the 

other way around.



There are valid reasons to learn lists of mnemonics, mostly for 

transitioning configurations from one flight regime to the next.  

Shutdown shouldn't be one of them.  All of my switches are in one 

place.  The shutdown procedure is to verify that all the switches are in 

the down position.  There is no point in anything more complicated.

earl_schroeder(at)juno.co
Guest

Posted: Mon Dec 08, 2008 2:46 pm Post subject: Need for start-up protection?

Hi Sam,

I have the IC-A200 (not TSO version) and 90% of time it is turned on when I crank the engine.  I have the 40A alt and the regulator from B&C.  After hundreds of starts, I have not found any problems.  I don't remember the fuse size but it is sized for wire protection.  Earl



You wrote:



I know this has been discussed before, but it's hitting a little closer to home, and I thought I'd bring it up again.



While installing my new ICOM IC-A210 com radio I found this little warning block in the pilot's instruction manual:

"CAUTION:  DO NOT turn the power ON until the aircraft engines have been started.  It is very important for protection of the power supply circuit."



(On the other hand, my Dynon D180 installation manual states several times that it is okay to have the unit on when starting).



For other matters of confusion, the ICOM Pilot's manual says "NEVER connect to a power source that is fused at more than 5A".  But the installation instructions say to use 18AWG wire with a 10 A circuit breaker.  The specifications listed on the web site says it uses up to 5A during transmitting.



So, how do I make sure the ICOM is always off before engine start?  Or should I not bother?  I have a B&C permenant magnet alternator.



Sam Hoskins

www.samhoskins.blogspot.com

Sam

Joined: 18 May 2008
Posts: 135

Posted: Mon Dec 08, 2008 3:11 pm Post subject: Need for start-up protection?

Thanks everyone.



Yes, using checklists is good airmanship.  However, I would like to make sure that if I FORGET, there will still be no catastrophe with my radio.  The feedback seems to be mixed that if even we forget, the radio will be able to handle it.

 

As an aside, I do training and consulting in Mistake-Proofing (cheap plug: www.mistakeproofing.net), also known in Japanese as Poka-Yoke.



The idea behind Mistake-Proofing is simply; even if someone forgets to do something, no damage occurs.  Dynon has done that.

  

I'll just have to do my best "remembering".

 	  Quote: 	
		  Sam 	




On Mon, Dec 8, 2008 at 12:11 PM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:

 [quote]  At 09:22 AM 12/8/2008, you wrote:

  	  Quote: 	
		  I know this has been discussed before, but it's hitting a little closer to home, and I thought I'd bring it up again.



 While installing my new  ICOM IC-A210 com radio I found this little warning block in the pilot's instruction manual:

 "CAUTION:  DO NOT turn the power ON until the aircraft engines have been started.  It is very important for protection of the power supply circuit." 	




    I've heard that this radio is at risk for damage to any

    voltages over 16v during an OV condition. There are no

    "spikes" that exceed this value during cranking but if

    the radio was not blessed with design goals conforming

    to DO160 recommendations, perhaps they're admitting

    to a vulnerability that most suppliers to the industry

    choose to live with.



 

  	  Quote: 	
		  (On the other hand, my Dynon D180 installation manual states several times that it is okay to have the unit on when starting). 	




    Yup, they probably did due diligence under the recommendations

    for DO160 compliance.



 

  	  Quote: 	
		  For other matters of confusion, the ICOM Pilot's manual says "NEVER connect to a power source that is fused at more than 5A".  But the installation instructions say to use 18AWG wire with a 10 A circuit breaker.  The specifications listed on the web site says it uses up to 5A during transmitting. 	




   The 5A breaker would be fine. Your transmissions are so

   short and the receive power so low that you're not likely

   to trip a 5A breaker. 



 

  	  Quote: 	
		  So, how do I make sure the ICOM is always off before engine start?  Or should I not bother?  I have a B&C permenant magnet alternator. 	




   Turn it off/on as part of your post/pre-flight checklist.



 

        Bob . . .



        ----------------------------------------)

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

        ----------------------------------------



      	  Quote: 	
		  



	




[b]

_________________
Sam Hoskins
www.samhoskins.blogspot.com

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Dec 08, 2008 3:16 pm Post subject: Need for start-up protection?

At 04:31 PM 12/8/2008, you wrote:

  	  Quote: 	
		  Nice post Earnest, I totally agree.  The responses to Sam's question have been disappointing. 

  

 I am NOT an electrical wiz.  That said, I think you are in need of a Transorb or TVS (Transient voltage Suppressor) Sam (or maybe Eric's Snap-Jacks??).  The purpose of these little guys is to protect devices from overvoltage conditions by clamping the voltage at some set point.  They are placed between the device and power supply.  I'm not good one to recommend part numbers but there are lots of possibilities at Digi-Key.

  

 My goal in using these in my plane was not to allow me to leave the power switch on all the time.  Rather, I wanted to avoid frying some peice of equipment when the day comes that I accidentally start/shutdown with something on.

  

 Jon 	




 



    At various times over 40+ years of hammering on 

    airplanes (and cars!) I've watched for start-up

    anomalies with sufficiently sophisticated equipment

    to capture and identify such gremlins. I've never

    seen a start-up spike and I've looked at systems

    running the gamut from C-150 to big Lears and

    Beechjets. 



    Equipment qualified under DO-160 guidelines can

    stand 20 volts for 1 second, 40 volts for 100

    mS. THESE conditions are possible during alternator

    load-dump without a battery on line. A combination

    of conditions that is exceedingly unlikely to 

    occur in an airplane conforming to architectures

    found in legacy design goals (Like the z-figures

    and 99% of all TC aircraft flying).



    It is not difficult to design products that comply

    with DO-160 guidelines. In 40+ years of supplying

    products to all manner of military and civil aircraft

    I've never had to ask a customer to "shut me off"

    for the purpose of start-up protection. Nowadays, the

    whole idea of spikes moves forward on fear of the

    unknown, unseen and un-demonstrated.



    Don't loose any sleep over it . . . save your money

    for more useful investments in system performance.

    "Spike" suppression isn't one of them.



    Bob . . .

         [quote][b]

schaefer(at)rts-services.
Guest

Posted: Tue Dec 09, 2008 6:21 am Post subject: Need for start-up protection?

Spikes are not always the problem. This would stem from poor startup regulation as the alternator comes on line.  

Low voltage (during cranking) can cause some solid state devices that normally operate in a switching mode to operate in a linear mode.  

This can cause a device that normally does not need to dissipate heat to get hot and potentially destroy itself.  

   

A Transorb or TVS will not protect against these types of problems.  

   

r.t.s.  

         

  

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of jon(at)finleyweb.net

 Sent: Monday, December 08, 2008 4:32 PM

 To: aeroelectric-list(at)matronics.com

 Subject: Re: AeroElectric-List: Need for start-up protection?  

  

     

Nice post Earnest, I totally agree.  The responses to Sam's question have been disappointing.   

    

   

    

I am NOT an electrical wiz.  That said, I think you are in need of a Transorb or TVS (Transient voltage Suppressor) Sam (or maybe Eric's Snap-Jacks??).  The purpose of these little guys is to protect devices from overvoltage conditions by clamping the voltage at some set point.  They are placed between the device and power supply.  I'm not good one to recommend part numbers but there are lots of possibilities at Digi-Key.  

    

   

    

My goal in using these in my plane was not to allow me to leave the power switch on all the time.  Rather, I wanted to avoid frying some peice of equipment when the day comes that I accidentally start/shutdown with something on.  

    

   

    

Jon  

    



 

 --

longg(at)pjm.com
Guest

Posted: Tue Dec 09, 2008 7:07 am Post subject: Need for start-up protection?

Exactly,  

Because airplanes seem to be so delicate, this is why we start our engines BEFORE we turn on those delicate instruments. Apparently airplane regulators are not as reliable as automotive regulators and batteries half the size of the one in my car appear more explosive.  

   

I suppose that is so we can see if were generating 220 volts (for making German coffee) before we turn on the $8000 Garmin and wipe it out. I also thought this is why I spent all of that money on the B & C OVP stuff? How many Snap-jack OVP, TVS devices does one need on these vulnerable systems? I think the original post is correct. Add to the checklist and just turn off the big $$ items before starting. Great advice.  

   

Glenn  

     

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of jon(at)finleyweb.net

 Sent: Tuesday, December 09, 2008 9:37 AM

 To: aeroelectric-list(at)matronics.com

 Subject: RE: AeroElectric-List: Need for start-up protection?  

  

     

Ok, then what is the answer?   I am one of the folks that just can't understand why this is not a problem in cars but is in aircraft. Does a car have a relay that disconnects all electronics during engine start or are the components better designed or ???  

    

   

    

Jon

 

 --

rlborger(at)mac.com
Guest

Posted: Tue Dec 09, 2008 7:13 am Post subject: Need for start-up protection?

Gents,



FWIW:



 I don't switch the Avionics Master on till after the engine is started and switch it off before I shut the engine down.  This procedure was drubbed into me back in the 60's when I was a student pilot and it has stuck with me since.  It is also in the check lists of the two aircraft I fly most frequently.  This procedure seems to preclude any issues of bus voltage drop or spikes affecting the expensive electrical goodies.



This morning, I observed what occurred when I started my 2007 Ford Ranger Pickup (manual & small V-6).  When the starter is engaged, the other electrical stuff drops off line till the starter is disengaged.  So it appears that in the case of my little pickup, there is some mechanism to disconnect the electronics (in my case, the AM/FM radio/CD player) when the engine is started.



Just my two cents...



Check six,

Bob Borger



On Tuesday, December 09, 2008, at 08:37AM, <jon(at)finleyweb.net> wrote:

 	  Quote: 	
		  

Ok, then what is the answer?   I am one of the folks that just can't understand why this is not a problem in cars but is in aircraft. Does a car have a relay that disconnects all electronics during engine start or are the components better designed or ???



 



Jon

mrspudandcompany(at)veriz
Guest

Posted: Tue Dec 09, 2008 7:33 am Post subject: Need for start-up protection?

Ok, then what is the answer?   I am one of the folks that just can't understand why this is not a problem in cars but is in aircraft. Does a car have a relay that disconnects all electronics during engine start or are the components better designed or ???  

    

   

  [quote]Jon



Most of us don’t even notice that when we turn the ignition switch, in our automobile, to the momentary start position, the radio and most accessories are turned off until the switch is released to run.  Do you suppose there is a reason for this??                Roger  [b]

jfogarty(at)tds.net
Guest

Posted: Tue Dec 09, 2008 8:02 am Post subject: Need for start-up protection?

Robert,  A key statement in your post is "buss voltage drop or spikes 

affecting the expensive electrical goodies."  I agree with your post 

totally.  Most of us building understand we do not want to damage our 

expensive electrical goodies, we only want to purchase them once! 

Consequently, we should follow our check list.  Just my two cents.



Jim



---

echristley(at)nc.rr.com
Guest

Posted: Tue Dec 09, 2008 8:34 am Post subject: Need for start-up protection?

Robert Borger wrote:

 	  Quote: 	
		   



 Gents,



 FWIW:



  I don't switch the Avionics Master on till after the engine is started and switch it off before I shut the engine down.  This procedure was drubbed into me back in the 60's when I was a student pilot and it has stuck with me since.  It is also in the check lists of the two aircraft I fly most frequently.  This procedure seems to preclude any issues of bus voltage drop or spikes affecting the expensive electrical goodies.

   

Great training, and you are to be commended for your good airmanship.  
	


That's not the issue, though.  The issue is whether the good training 

serves any purpose or if it is just an extra hazing point.



The spikes have never been shown to exist.  Short of a stuck bendix gear 

turning the starter into a generator, I've not heard of any theory that 

explains how a spike COULD exist.



If the low voltage does damage to the radio during the few seconds that 

you are cranking, what is it going to do the day your alternator drops 

offline and you have a low voltage for many minutes.  Will your radio 

burn up during the situation when you need it most?  If this was a 

common problem with radios when pilots encountered electrical problems, 

wouldn't we have heard about it?  Mostly what I've heard is more along 

the lines of pilots talking to center to get help until their battery 

runs out completely. 



And how about working on your avionics on the ground.  If your 

troubleshooting and your battery starts to run down, do you run the risk 

of burning up your radio?



 	  Quote: 	
		   This morning, I observed what occurred when I started my 2007 Ford Ranger Pickup (manual & small V-6).  When the starter is engaged, the other electrical stuff drops off line till the starter is disengaged.  So it appears that in the case of my little pickup, there is some mechanism to disconnect the electronics (in my case, the AM/FM radio/CD player) when the engine is started.

   

Could it be so that all of the batteries power can be used to crank the 
	


engine?  This would also be a valid reason to turn off everything in an 

airplane before start, but is totally unrelated to protecting 

electronics from some ghostly danger that hasn't been shown to exist and 

can't exist if our theories of DC electronics hold water.

dgolden(at)golden-consult
Guest

Posted: Tue Dec 09, 2008 8:50 am Post subject: Need for start-up protection?

Ernest Christley wrote:



 	  Quote: 	
		   Could it be so that all of the batteries power can be used to crank the

 engine?  This would also be a valid reason to turn off everything in an

 airplane before start, but is totally unrelated to protecting

 electronics from some ghostly danger that hasn't been shown to exist and

 can't exist if our theories of DC electronics hold water.


	


Yes, because that big old air conditioner is also running of the same

accessory circuit. You don't want those kinds of loads on the engine

while trying to start it.



Dennis

-- 

Dennis Golden

Golden Consulting Services, Inc.

rhdudley1(at)bellsouth.ne
Guest

Posted: Tue Dec 09, 2008 9:33 am Post subject: Need for start-up protection?

It is amazing how deeply embedded the myth is. I have heard it from many 

flight instructors and read many posts promoting it on this list. Even after 

the technology has progressed and the specifications require tolerance, the 

myth persists. I am inclined to believe Bob Nuckolls assertions based on a 

long history in the industry and his many attempts to find the illusive 

"killer spike". It is too bad to have to include unnecessary and redundant 

steps in your procedures that continue to feed that myth. And even add a 

single point potential failure in the form of an "avionics master". The myth 

will never go away! Also watch out for black cats, ladders and broken 

mirrors. A little salt over the shoulder before each flight might help.



Regards to all,



Richard Dudley

---

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Dec 09, 2008 2:20 pm Post subject: Need for start-up protection?

At 09:29 AM 12/9/2008, you wrote:

  	  Quote: 	
		    

 Ok, then what is the answer?   I am one of the folks that just can't understand why this is not a problem in cars but is in aircraft. Does a car have a relay that disconnects all electronics during engine start or are the components better designed or ??? 	


   It's not a "problem" in cars. That shutdown of the

   accessories in automobiles is for load shedding during

   cranking that maximizes available energy from the battery

   for starting. This is especially important when the

   battery is nearing failure from age or abuse.



  	  Quote: 	
		    

 

  	  Quote: 	
		  Jon



Most of us

don’t even notice that when we turn the ignition switch, in our

automobile, to the momentary start position, the radio and most

accessories are turned off until the switch is released to run.  Do

you suppose there is a reason for this??

	
	


   The most complex components in your car are used to

   orchestrate fuel and ignition control. Obviously,

   these cannot be turned off during cranking . . .

   the car would never start!



   The path to Nirvana is found by simply designing

   accessories to dance to the music described in

   DO-160 and similar documents for other industries.

   See:



  http://www.aeroelectric.com/articles/DO-160.pdf



  http://www.aeroelectric.com/articles/avmaster.pdf



  http://www.aeroelectric.com/articles/Crowbar_OV_Protection/Load_Dump_A.pdf 



  http://www.aeroelectric.com/articles/Crowbar_OV_Protection/DC_Power_System_Dynamics_C.pdf 



   My points are (1) it's stone simple to design products

   that live happily with anything the ship's bus can

   throw at it and (2) it's been done by ALL suppliers

   to TC aircraft for 35+ years and most suppliers

   to OBAM aircraft (including the 'Connection) for

   20+ years. Finally, (3) in spite of many queries to folks

   who worked in TC aircraft community (like Narco, King,

   Terra, Lear, Cessna, Beech, Wilcox, etc), not one

   individual has come forward to identify the source,

   character and total energy contained in the most feared

   "spike". It's one of those deeply held beliefs that

   endures to this day: "I know spikes exist because

   folks have worshiped at the altar of AV master switches

   for decades . . . can that many true believers be

   wrong?"



   Nobody would happier to be proven in error about this

   than I. Once the source is identified, simple repeatable

   experiments will confirm its existence and magnitude.

   I'd be pleased to write an article about it . . . and

   cite co-authorship to the individual who discovers

   (a) what does it, (b) how is it shaped, and (c)how much energy

   does it contain?



 

        Bob . . .



        ----------------------------------------)

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

        ----------------------------------------



     [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Dec 09, 2008 2:39 pm Post subject: Need for start-up protection?

At 11:31 AM 12/9/2008, you wrote:

 	  Quote: 	
		  

<rhdudley1(at)bellsouth.net>



  It is too bad to have to include unnecessary and redundant steps 

 in your procedures that continue to feed that myth. And even add a 

 single point potential failure in the form of an "avionics master". 

 The myth will never go away! Also watch out for black cats, ladders 

 and broken mirrors. A little salt over the shoulder before each 

 flight might help.


	


   Our customer base tends to help perpetuate the myth too.

   I had this discussion with numerous folks at Beech/RAC over

   a period of 20 years. All agreed that the AV Master could

   be dispensed with. Marketing objected stating that it was

   too much a part of the operating procedure and they didn't

   want to introduce new features that high time pilots might

   find troubling. It was decided that genuflecting at the

   altar of AV master switches would continue although that deity

   seems to have vacated the temple many years ago.



        Bob . . .



        ----------------------------------------)

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

        ----------------------------------------

frank.hinde(at)hp.com
Guest

Posted: Tue Dec 09, 2008 3:13 pm Post subject: Need for start-up protection?

As for me..Having my entire avionics stack that I risk my  life on in IMC to one master switch with one fuse is not  smart.

  

 For me I have 4 switches to turn off before  start/shutdown..Its just not a big deal to turn them off..and if i forget then  its probably not an issue anyway.

  

 Frank



   From:  owner-aeroelectric-list-server(at)matronics.com  [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Robert  L. Nuckolls, III

Sent: Tuesday, December 09, 2008 2:19  PM

To: aeroelectric-list(at)matronics.com

Subject: RE:  Need for start-up protection?

 

At 09:29 AM 12/9/2008, you wrote:

  	  Quote: 	
		  

Ok, then what is the answer?   I am one of the folks that    just can't understand why this is not a problem in cars but is in aircraft.    Does a car have a relay that disconnects all electronics during engine start    or are the components better designed or ??? 	


  It's  not a "problem" in cars. That shutdown of the

  accessories in  automobiles is for load shedding during

  cranking that maximizes  available energy from the battery

  for starting. This is especially  important when the

  battery is nearing failure from age or  abuse.



 [quote] [b]

riggs_la(at)yahoo.com
Guest

Posted: Tue Dec 09, 2008 3:27 pm Post subject: Need for start-up protection?

I started my flying with the military and they did not have a master

avionics switch, so when I started flying civilian aircraft with the master

avionics switch I thought this is cool you do not have to turn on each radio

individually you do it with just one switch.  I thought it was just for

convenience.  My aircraft will have a master avionics switch. 



Lynn A. Riggs

http://home.comcast.net/~lariggs/wsb/html/view.cgi-home.html-.html

--

fvalarm(at)rapidnet.net
Guest

Posted: Tue Dec 09, 2008 6:40 pm Post subject: Need for start-up protection?

Bob,



I too have never understood the fear of a voltage "spike" during engine

start BUT, I always assumed  that while the average pilot may not know

what's going on here electrically,  he may have reason to be concerned just

the same.  I always thought one could assume that during engine cranking,

the buss voltage would sag.  This sagging would "under power" the

electronics currently turned on, and it would be this extreme low voltage

event that would cause damage to sensitive things.  I call it a "brown out"

and many electronics don't like it. They malfunction in many ways. Sort of

like not knowing whether they're supposed to be off, or on, or...off,  no

on  etc.  



In your experience, could this voltage sag for several seconds cause trouble

for some electronics (certified or not) in aircraft?



Bevan

RV7A wiring   



--

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours Goto page 1, 2 Next
Page 1 of 2

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum