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NTSB recommends grounding of 601XLs in US
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BobCollins

Joined: 12 Aug 2008
Posts: 19
Location: Sunnyvale CA USA

Posted: Tue Apr 14, 2009 6:54 pm Post subject: NTSB recommends grounding of 601XLs in US

This is an interesting discussion to watch. Bryan, you are probably 

correct that the FAA would not be able to ground all the E-ABs out there 

but the FAA (and Zenith) would be well advised to "encourage" them to 

not fly if the FAA grounds the S-LSAs.

I read the NTSB recommendation and it seems to raise some valid concerns 

about the design of the ailerons. If I were to put my life on the line, 

I would want a well researched rebuttal to the NTSB letter before I 

would fly it again. It is also not a case of the quality of the home 

builder that is being discussed here, assuming (s)he followed the plans. 

The NTSB is talking about a design issue which I really doubt any of the 

builders made significant changes to.

The NTSB identifies two possible issues here. First, which Zenith agrees 

with, is maintaining the proper tension in the control cables. This is 

apparently critical to the design and Zenith should have identified it 

as such from the beginning. As a design, requiring the owner to inspect 

and measure the tension in the cables regularly seems like a poor choice 

if there is a low or no maintenance option such as mass-balancing.

Second, the NTSB raises doubt whether the design is dynamically stable 

even with the cables in proper tension. They don't cite much to support 

this but I would want to see more investigation on this before my butt 

is on the line.

I was also very surprised to read about the apparently non-standard (and 

inconsistent) techniques used to measure airspeeds for the design.

I agree with George that this could turn into a circus which would not 

be good for anyone. We need reasonable follow-through without either 

hysteria or head-in-the-sand.

I have a question to the 601 cognoscenti, how are the XL ailerons 

designed differently then the HD(S) ones? The NTSB letter was quite 

specific to the 601XL.

Bob Collins

Sunnyvale CA USA

Bryan Martin wrote:

 	  Quote: 	

 <bryanmmartin(at)comcast.net>

 The FAA may be able to ground the S-LSAs, but there would be a real 

 problem grounding the E-ABs. There is no type certificate to take 

 action against. Each airplane is considered one of a kind. Many of the 

 E-ABs out there don't even have Zenith or Zodiac on the airworthiness 

 certificate. A person could build one and call it a Jones Gee-Whizz 

 Special on the certificate, then how could the FAA track it down? I 

 don't think there has been a single time in the history of the E-AB 

 category that the FAA has ever even considered grounding an 

 experimental design.

 Another thing is that the FAA doesn't have to pay any attention to 

 recommendations from the NTSB, and they often don't.

 F**k 'em, if I get the chance to fly mine to Sun'N'Fun this year, I 

 will. I'm not worried in the least about getting grounded by this BS. 

 I'm getting pretty tired of the government trying to protect me from 

 me. That's not the freaking job I'm paying them to do.

 On Apr 14, 2009, at 6:37 PM, DaveG601XL wrote:

> 

> <david.m.gallagher(at)ge.com>

>

> Well the timing of this puts one heck of a bind on anybody's plans to 

> fly to Sun-N-Fun next week in a 601XL.  Myself in particular.  I have 

> confidence in my airplane making the trip, but I cannot afford to get 

> grounded in Florida.  I too, hope that this motivates action for 

> whatever the proposed modifications.  I do not want to spend all 

> summer being grounded!!

>

> --------

> David Gallagher

> 601 XL/Jabiru 3300

> First flight 7/24/08

> 70 hours and climbing!

psm(at)att.net
Guest

Posted: Tue Apr 14, 2009 7:10 pm Post subject: NTSB recommends grounding of 601XLs in US

Hi Bob,



I am not familiar with any design except the XL (with which I have 

spent every day for the last 4 years).  I believe the basic design of 

the ailerons is similar on all models, but the wing shape and general 

design is quite different on the XL.



The XL has a tapered wing.  The other models (forgetting the 650 

which is really an XL with a different name) have Hershey bar wings 

(I think).  Also the center section of the other models extends a 

considerable way out the wing while the XL is straight from the 

fuselage to the wing tip.  I believe these major differences in the 

wing shape will be more significant than the actual aileron shape or design.



The XL can be built with either hinge-less or piano hinged 

ailerons.  I suspect this doesn't make much difference with regard to 

the NTSB paper on flutter.



Paul

XL on hold

At 07:52 PM 4/14/2009, you wrote:



 	  Quote: 	
		  I have a question to the 601 cognoscenti, how are the XL ailerons 

designed differently then the HD(S) ones? The NTSB letter was quite 

specific to the 601XL.

hills(at)sunflower.com
Guest

Posted: Tue Apr 14, 2009 7:14 pm Post subject: NTSB recommends grounding of 601XLs in US

Bob;



Well, I for one have push rods on my 601 HDS, so that's one difference (no

cables to go slack).   Also, I have a big fat wing that probably resist

flapping and/or breaking to a greater degree than the 601XL wing, even if a

flutter does occur.



Roger



--

JAPhillipsGA(at)aol.com
Guest

Posted: Tue Apr 14, 2009 7:29 pm Post subject: NTSB recommends grounding of 601XLs in US

Anybody notice the date of the NTSB letter to the  FAA?

  In a message dated 4/14/2009 11:14:31 P.M. Eastern Daylight Time,  hills(at)sunflower.com writes:

  	  Quote: 	
		  -->    Zenith-List message posted by: "Roger & Lina Hill"    <hills(at)sunflower.com>

Bob;

Well, I for one have push    rods on my 601 HDS, so that's one difference (no

cables to go    slack).   Also, I have a big fat wing that probably    resist

flapping and/or breaking to a greater degree than the 601XL wing,    even if a

flutter does occur.

Roger

-----Original    Message-----

From:    owner-zenith-list-server(at)matronics.com

[mailto:owner-zenith-list-server(at)matronics.com]    On Behalf Of Bob Collins

Sent: Tuesday, April 14, 2009 9:52 PM

To:    zenith-list(at)matronics.com

Subject: Re: Re: NTSB recommends    grounding of 601XLs in US

--> Zenith-List message posted by: Bob    Collins <bobcollins42(at)gmail.com>

This is an interesting    discussion to watch. Bryan, you are probably 

correct that the FAA would    not be able to ground all the E-ABs out there 

but the FAA (and Zenith)    would be well advised to "encourage" them to 

not fly if the FAA grounds    the S-LSAs.

I read the NTSB recommendation and it seems to raise some    valid concerns 

about the design of the ailerons. If I were to put my life    on the line, 

I would want a well researched rebuttal to the NTSB letter    before I 

would fly it again. It is also not a case of the quality of the    home 

builder that is being discussed here, assuming (s)he followed the    plans. 

The NTSB is talking about a design issue which I really doubt any    of the 

builders made significant changes to.

The NTSB identifies    two possible issues here. First, which Zenith agrees 

with, is maintaining    the proper tension in the control cables. This is 

apparently critical to    the design and Zenith should have identified it 

as such from the    beginning. As a design, requiring the owner to inspect 

and measure the    tension in the cables regularly seems like a poor choice 

if there is a low    or no maintenance option such as mass-balancing.

Second, the NTSB    raises doubt whether the design is dynamically stable 

even with the cables    in proper tension. They don't cite much to support 

this but I would want    to see more investigation on this before my butt 

is on the line.

I    was also very surprised to read about the apparently non-standard (and    

inconsistent) techniques used to measure airspeeds for the    design.

I agree with George that this could turn into a circus which    would not 

be good for anyone. We need reasonable follow-through without    either 

hysteria or head-in-the-sand.

I have a question to the 601    cognoscenti, how are the XL ailerons 

designed differently then the HD(S)    ones? The NTSB letter was quite 

specific to the 601XL.

Bob    Collins

Sunnyvale CA USA

Bryan Martin wrote:

 	  Quote: 	
		   -->    Zenith-List message posted by: Bryan Martin 

    <bryanmmartin(at)comcast.net>

 The FAA may be able to ground    the S-LSAs, but there would be a real 

 problem grounding the E-ABs.    There is no type certificate to take 

 action against. Each airplane is    considered one of a kind. Many of the 

 E-ABs out there don't even have    Zenith or Zodiac on the airworthiness 

 certificate. A person could    build one and call it a Jones Gee-Whizz 

 Special on the certificate,    then how could the FAA track it down? I 

 don't think there has been a    single time in the history of the E-AB 

 category that the FAA has ever    even considered grounding an 

 experimental design.

    Another thing is that the FAA doesn't have to pay any attention to 

    recommendations from the NTSB, and they often don't.

 F**k 'em,    if I get the chance to fly mine to Sun'N'Fun this year, I 

 will. I'm    not worried in the least about getting grounded by this BS. 

 I'm    getting pretty tired of the government trying to protect me from 

 me.    That's not the freaking job I'm paying them to do.

 On Apr 14,    2009, at 6:37 PM, DaveG601XL wrote:

> --> Zenith-List    message posted by: "DaveG601XL" 

>    <david.m.gallagher(at)ge.com>

>

> Well the timing of    this puts one heck of a bind on anybody's plans to 

> fly to    Sun-N-Fun next week in a 601XL.  Myself in particular.  I have    

> confidence in my airplane making the trip, but I cannot afford to    get 

> grounded in Florida.  I too, hope that this motivates    action for 

> whatever the proposed modifications.  I do not    want to spend all 

> summer being grounded!!

>

>    --------

> David Gallagher

> 601 XL/Jabiru    3300

> First flight 7/24/08

> 70 hours and  ================================================ the  ties  Day  ================================================               - MATRONICS WEB FORUMS  ================================================             - List Contribution Web Site  sp;                             ===================================================

 Access 350+ FREE radio stations anytime from anywhere on the web. Get the Radio Toolbar!

  [quote][b]

ggower_99(at)yahoo.com
Guest

Posted: Tue Apr 14, 2009 8:14 pm Post subject: NTSB recommends grounding of 601XLs in US

Could it be the date April 1st  (April fool) Joke for you guys in USA?

  

 Saludos

 Gary Gower...

 



--- On Tue, 4/14/09, JAPhillipsGA(at)aol.com <JAPhillipsGA(at)aol.com> wrote:



 [quote]From: JAPhillipsGA(at)aol.com <JAPhillipsGA(at)aol.com>

Subject: Re: Re: NTSB recommends grounding of 601XLs in US

To: zenith-list(at)matronics.com

Date: Tuesday, April 14, 2009, 11:25 PM



  Anybody notice the date of the NTSB letter to the FAA?

  

  In a message dated 4/14/2009 11:14:31 P.M. Eastern Daylight Time, hills(at)sunflower.com writes:

 [quote]--> Zenith-List message posted by: "Roger & Lina Hill" <hills(at)sunflower.com>

Bob;



Well, I for one have push rods on my 601 HDS, so that's one difference (no

cables to go slack).   Also, I have a big fat wing that probably resist

flapping and/or breaking to a greater degree than the 601XL wing, even if a

flutter does occur.



Roger



--

grs-pms(at)comcast.net
Guest

Posted: Tue Apr 14, 2009 8:32 pm Post subject: NTSB recommends grounding of 601XLs in US

It was dated today, the 14th.

  

 George

  

 Do not archive

 [quote]   ---

pchap(at)primus.ca
Guest

Posted: Tue Apr 14, 2009 9:14 pm Post subject: NTSB recommends grounding of 601XLs in US

While the NTSB presumably doesn't have to give anyone a heads-up on anything, it is disappointing that Zenith "wasn't ahead of the story" on this at all, even if it may not have been their fault. 



 It seems ironic to have received an emailed newsletter from Zenith that is "all sunshine", on the same day of the NTSB letters, April 14. 



 I haven't been keeping close track, but the last I heard from Zenith was that they'd participate in the European load tests, but weren't really expecting to spend the money to test to the US standards too. That  was late in February. Also, in a Chris Heintz letter responding to the British LAA restrictions the same month, he basically wrote that everything was rosy with the NTSB. Correct me if I'm wrong. 



 Sorry to say but Zenith were either blind, blindsided, or keeping us in the blind. 



 

 Peter Chapman

 Toronto, ON     [quote][b]

Matt Ronics

Joined: 30 Apr 2007
Posts: 22

Posted: Tue Apr 14, 2009 10:32 pm Post subject: Re: NTSB recommends grounding of 601XLs in US

 "While the NTSB presumably doesn't have to give anyone a heads-up on anything, it is disappointing that Zenith "wasn't ahead of the story" on this at all, even if it may not have been their fault.....



...Sorry to say but Zenith were either blind, blindsided, or keeping us in the blind." 

   



"Let me assure everyone that Zenair is in close contact with the NTSB on this matter, and that if anything is discovered that could affect the safety of the Zodiac fleet, we will be notified immediately."  (from Chris Heintz's letter April 24, 2008)



This whole issue stinks, no matter how you look at it.  



I wish they would produce a match-hole drilled 601HD/S kit.

aerobat

Joined: 07 Nov 2008
Posts: 21
Location: UK

Posted: Tue Apr 14, 2009 11:32 pm Post subject: Re: NTSB recommends grounding of 601XLs in US

This is pretty much in line with what the LAA in the UK have said. One aircraft is currently being modified with aileron mass balances and a beefing up of the wing spar carry through so they can then evaluate it.

bryanmmartin

Joined: 10 Jan 2006
Posts: 1018

Posted: Wed Apr 15, 2009 3:38 am Post subject: NTSB recommends grounding of 601XLs in US

The original plane for the XL, like the HD, had the "hingeless"  

ailerons. The original prototype has this design, it has been flown  

for hundreds of hours to airshows all over the country for over nine  

years now with no trouble. Many builders changed the design to piano  

hinge ailerons and the AMD S-LSA has piano hinge ailerons because  

"real airplanes have hinges". As far as I know, all of the accident  

aircraft had the piano hinge ailerons. It stands to reason that the  

dynamic response of the two different aileron designs are going to be  

different due to the elastic properties of the "hingeless" design that  

is missing on the piano hinge design. I suspect that the elasticity of  

the hingeless design makes the resonant frequency fall farther outside  

of the flight envelope of the airplane. Mine has the hingeless  

ailerons. I have 265 hours on mine and have flown it to the far edges  

of the flight envelope and slightly beyond during phase one testing  

with no hint of flutter. I'm convinced that my airplane is  safe  

enough for the type of flying I do.

On Apr 14, 2009, at 10:52 PM, Bob Collins wrote:

 	  Quote: 	
		  

 I have a question to the 601 cognoscenti, how are the XL ailerons  

 designed differently then the HD(S) ones? The NTSB letter was quite  

 specific to the 601XL.



 Bob Collins

 Sunnyvale CA USA




	


-- 

Bryan Martin

N61BM, CH 601 XL,

RAM Subaru, Stratus redrive.

do not archive.

_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive.

Juan Vega Jr

Joined: 13 Jan 2009
Posts: 157

Posted: Wed Apr 15, 2009 12:04 pm Post subject: NTSB recommends grounding of 601XLs in US

in reading this faa letter, it seems that someone has been lobbying the safety board to ground the plane and that this report was done based on someones lobbying efforts copying the safety on the emails on this site.  I would love to know who is the S%#(at)thead that was hell bent on pushing this.  



Juan

--

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Wed Apr 15, 2009 12:26 pm Post subject: Re: NTSB recommends grounding of 601XLs in US

There were copied e-mails from Matronics in the recommendation? Honestly, I'm kind of up in the air personally about seeing this getting a once over from the FAA. Be nice to know for sure, certainly sounds like aileron flutter. Certainly never wanted to see any publicity about it though. Any publicity there is though I'd say probably has more to do with foreign safety boards grounding the XL. Doubt there was anyone actively lobbying for it here.



 	  Juan Vega Jr wrote: 	
		  in reading this faa letter, it seems that someone has been lobbying the safety board to ground the plane and that this report was done based on someones lobbying efforts copying the safety on the emails on this site.  I would love to know who is the S%#(at)thead that was hell bent on pushing this.  



Juan

--

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Wed Apr 15, 2009 12:30 pm Post subject: Re: NTSB recommends grounding of 601XLs in US

 	  ashontz wrote: 	
		   Doubt there was anyone actively lobbying for it here.

	




Andy, please don't take this the wrong way. But you are being terribly naive. It is quite obvious who was lobbying for. It is in the report.

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Wed Apr 15, 2009 12:41 pm Post subject: Re: NTSB recommends grounding of 601XLs in US

Sorry, didn't register with me the first time I read the report. I went back and checked, I guess you're talking about the ZBAG engineer reference on page



First off, I was just a guess on the ZBAG list, had never paid, and had backed out simply because I didn't want to see any of this crap go down soon as I heard someone mention lawyer.



Anyway, what's it's any business of the hired engineer to report anything to the NTSB. Wasn't he supposed to be reporting to ZBAG?



Hopefully the FAA will tell him to go sh$t in his flat hat and pull it down over his ears. It's pretty obvious what's wrong with the plane, aileron flutter. Fix it however you want, personally I'm going with counter balance weights.



But, at the same time, I can see the FAA getting involved now because after all, everyone had to have their sport pilot rated airplanes, we'll here they are in all their certification glory.



 	  Gig Giacona wrote: 	
		   	  ashontz wrote: 	
		   Doubt there was anyone actively lobbying for it here.

	




Andy, please don't take this the wrong way. But you are being terribly naive. It is quite obvious who was lobbying for. It is in the report.

jeffrey_davidson(at)earth
Guest

Posted: Wed Apr 15, 2009 1:06 pm Post subject: NTSB recommends grounding of 601XLs in US

On the HD, the ailerons are full length and the belcrank is in the gap between the center wing seciton and the outboard wing sections.  Same for the HDS.  Both have three part wings center section and two outborad sections.  The HD wing has a constant chord and is longer than the tapered HDS wings.  On the XL/650, the ailerons are roughly half the length of the wing.  The inner half length is used for the flaps.  The HD and HDS do not have flaps.  On the XL, the aileron bellcranks are further out in the wing which means that the control cables have a longer run.

Jeff Davidson 



The original plane for the XL, like the HD, had the "hingeless"  

ailerons. The original prototype has this design, it has been flown  

for hundreds of hours to airshows all over the country for over nine  

years now with no trouble. Many builders changed the design to piano  

hinge ailerons and the AMD S-LSA has piano hinge ailerons because  

"real airplanes have hinges". As far as I know, all of the accident  

aircraft had the piano hinge ailerons. It stands to reason that the  

dynamic response of the two different aileron designs are going to be  

different due to the elastic properties of the "hingeless" design that  

is missing on the piano hinge design. I suspect that the elasticity of  

the hingeless design makes the resonant frequency fall farther outside  

of the flight envelope of the airplane. Mine has the hingeless  

ailerons. I have 265 hours on mine and have flown it to the far edges  

of the flight envelope and slightly beyond during phase one testing  

with no hint of flutter. I'm convinced that my airplane is  safe  

enough for the type of flying I do.

On Apr 14, 2009, at 10:52 PM, Bob Collins wrote:

 	  Quote: 	
		  

 I have a question to the 601 cognoscenti, how are the XL ailerons  

 designed differently then the HD(S) ones? The NTSB letter was quite  

 specific to the 601XL.



 Bob Collins

 Sunnyvale CA USA

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Wed Apr 15, 2009 1:21 pm Post subject: Re: NTSB recommends grounding of 601XLs in US

Who has the plane that experienced flutter over the power plant? Did that badboy have hinged or hingless ailerons?



Also, in this Zenair newsletter, did this plance have hinged or hingeless.



http://www.zenair.org/nuke/modules.php?name=News&file=article&sid=17



 	  jeffrey_davidson(at)earth wrote: 	
		  

The original plane for the XL, like the HD, had the "hingeless"  

ailerons. The original prototype has this design, it has been flown  

for hundreds of hours to airshows all over the country for over nine  

years now with no trouble. Many builders changed the design to piano  

hinge ailerons and the AMD S-LSA has piano hinge ailerons because  

"real airplanes have hinges". As far as I know, all of the accident  

aircraft had the piano hinge ailerons. It stands to reason that the  

dynamic response of the two different aileron designs are going to be  

different due to the elastic properties of the "hingeless" design that  

is missing on the piano hinge design. I suspect that the elasticity of  

the hingeless design makes the resonant frequency fall farther outside  

of the flight envelope of the airplane. Mine has the hingeless  

ailerons. I have 265 hours on mine and have flown it to the far edges  

of the flight envelope and slightly beyond during phase one testing  

with no hint of flutter. I'm convinced that my airplane is  safe  

enough for the type of flying I do.

On Apr 14, 2009, at 10:52 PM, Bob Collins wrote:

 	  Quote: 	
		  

 I have a question to the 601 cognoscenti, how are the XL ailerons  

 designed differently then the HD(S) ones? The NTSB letter was quite  

 specific to the 601XL.



 Bob Collins

 Sunnyvale CA USA

hansriet

Joined: 09 Feb 2007
Posts: 93

Posted: Wed Apr 15, 2009 1:23 pm Post subject: Re: NTSB recommends grounding of 601XLs in US

[quote="bryanmmartin"]Many builders changed the design to piano  

hinge ailerons 

[/quote]



Well that's not entirely correct. The builders didn't change the plans, they merely opted for this factory option.

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Wed Apr 15, 2009 1:25 pm Post subject: Re: NTSB recommends grounding of 601XLs in US

True, I remember watching the video years ago and they spent all kinds of time talking about the hingeless aileron, then said that hinged is optional. Personally, I thought, "Hhhhhmmmm, hinged sounds better."



 	  hansriet wrote: 	
		   	  bryanmmartin wrote: 	
		  Many builders changed the design to piano  

hinge ailerons 

	




Well that's not entirely correct. The builders didn't change the plans, they merely opted for this factory option.

sperry50(at)comcast.net
Guest

Posted: Wed Apr 15, 2009 1:41 pm Post subject: NTSB recommends grounding of 601XLs in US

I got no choice when I purchased the quick-build kit. It came with piano

hinges!



DO NOT ARCHIVE



--

bryanmmartin

Joined: 10 Jan 2006
Posts: 1018

Posted: Wed Apr 15, 2009 2:05 pm Post subject: NTSB recommends grounding of 601XLs in US

Some builders were putting in piano hinges before they were offered as  

a factory option. They were eventually offered as an option due to  

popular demand.



On Apr 15, 2009, at 5:23 PM, hansriet wrote:



 	  Quote: 	
		   



  	  bryanmmartin wrote: 	
		  Many builders changed the design to piano

 hinge ailerons

 	




 Well that's not entirely correct. The builders didn't change the  

 plans, they merely opted for this factory option.




	


-- 

Bryan Martin

N61BM, CH 601 XL,

RAM Subaru, Stratus redrive.

do not archive.

_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive.

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