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Yak 52 r/h gear failure
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Yakmech

Joined: 19 Jan 2006
Posts: 6
Location: Melbourne Australia

Posted: Thu Jan 19, 2006 4:03 am Post subject: Yak 52 r/h gear failure

for those of you that might be interested.  Just before xmas I was test flying a yak 52 for a customer after service. On the landing roll the right gear collapsed at on roll out.  To cut a long storey short, the aircraft in question was 32 hours old.. the right gear actuating Ram had the internal locking collar assembled 180 degrees out.  The result of this incorrect assembly meant that with a sharp bump the gear could unlock and retract .  And yes before you ask .. the gear selector was in the neatural position. ( yes I know it's not supposed to be ).  The fault was not picked up during normal servicing of the aircraft.  The gear reacted normally to retraction and extension checks both normal and emergency.  When the gear was down and the air pressure removed from the down side of the ram the gear could be unlocked by a sharp blow with the palm of your hand on the drag brace at the ram attach point.  I might add that in this same position you could literally kick the gear from behind attempting to retract it and it would not move... it was only with a blow to the drag brace that the gear unlocked.   

Fortunately in this case the aircraft was travelling slowly when it collapsed and caused only minor damage to wing tip and aileron.  

If you would like any further info or pictures of the ram.  pm me with your email address and I will forward them on to you.

Finaly, as stated earlier the aircraft had only done 32 hours from new and it appears that the ram has come out of the Factory like this.  One to check on, next your Yak 52 in for a service..

_________________
Once you have experienced flight you will forever walk this earth with your eyes turned skyward for it is there that you have been and there that you long to return !

mark.j(at)yakuk.com
Guest

Posted: Fri Jan 20, 2006 12:54 am Post subject: Yak 52 r/h gear failure

Gents, take this with a pinch of salt, ask the witnesses to this pilot/ mechanic accident. There is a lot of BS and â€œpride/ reputationâ€ trying to be protected here.   

 

BTW, I have just has a gear ram on the bench and assembled it wrongly for a test.  



We all know why the gear collapses on the landing/ taxi role don't we ? No if and buts, this accident was entialy pilot error.   

  

Take care and fly with hull insurance, we can all make mistakes.

Yakmech

Joined: 19 Jan 2006
Posts: 6
Location: Melbourne Australia

Posted: Fri Jan 20, 2006 1:21 am Post subject: Re: Yak 52 r/h gear failure

this is what you get for trying to keep others from suffering the same fate.... all you have to do to test it is as i said.   the system was re installed as I have described for a demonstration for the insurance company and OTHER NON BELIEVERS....... and yes the witness's to the accident were there and NOW have appologised to me for the roumors that were being spread.  They have no doubt that it occured.  I hope that others are not as cynical as you,,, there were non beleivers here too... But not any more.  Oh and I take my job seriously.... I am an Aircraft Engineer and peoples lives depend on me.... what use is it for me to Lie about this sort of thing.  If this is the sort of reply that im going to get off this site then in future I will keep the information to myself and let you deal with the posssible consequenc's later.   I posted this info after one of the non believers told me about the site....... Sorry for trying to help out and prevent the same from occuring again......

_________________
Once you have experienced flight you will forever walk this earth with your eyes turned skyward for it is there that you have been and there that you long to return !

dsavarese(at)elmore.rr.co
Guest

Posted: Fri Jan 20, 2006 5:35 am Post subject: Yak 52 r/h gear failure

Mark,



Although you are correct in saying we all know why the gear  collapses on the landing/roll out/taxi, I think it is inappropriate to imply  that Mick used an incorrectly assembled actuator as the cause of the  incident?and then proceeded to tell?the world what happened.? I  seriously doubt?very many of us?would bother to tell the world?we  had a wing drop to the ground if it was caused by pure pilot error.? I for  one believe Mick and appreciate him advising us of what he found during his  investigation.?? Heck, he even admitted he had the gear handle in  neutral.



The reason why this never occurred in the previous 32 hours of  operation was because the gear handle was most likely never in the neutral  position before while the airplane was landing, rolling out or taxiing.?  ?If Mick had put the gear handle in the DOWN position, there would have  been an adequate amount of air pressure on the down side of the actuator to  prevent this from happening.



Dennis

dsavarese(at)elmore.rr.co
Guest

Posted: Fri Jan 20, 2006 5:41 am Post subject: Yak 52 r/h gear failure

Mick,

Don't ever apologize for sharing your experience.  I most definitely 

appreciate it.  But I must say this.  If the gear handle had been in the 

DOWN position at the time, the incident would have not occurred because 

there would have been air pressure on the down side of the actuator.  That 

is why this never occurred in the previous 32 hours of operation.  The only 

way you would have found out would be either on jacks with the gear handle 

in neutral and you specifically pushed on the drag link in an effort to test 

the locking mechanism of the actuator.  Or of course, the way you found out 

about it ie: the hard way.

Thanks for sharing with us.

Dennis



---

wlannon(at)cablerocket.co
Guest

Posted: Fri Jan 20, 2006 9:37 am Post subject: Yak 52 r/h gear failure

Mark;



I tend to agree with Dennis on this one. Sure  emough it was pilot error for not having the handle in? the down position.  But to say it was ENTIRELY pilot error is a stretch. If the ball lock was  correctly assembled AND not function tested after assembly it would not likely  have happened. Seems that ?there were two equally contributing screw up's  in this case and as you said we can all make mistakes. I think Mick deserves our  respect for bring it to our attention.



Cheers;

Walt

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Fri Jan 20, 2006 10:05 am Post subject: Yak 52 r/h gear failure

Walter Lannon wrote:

 	  Quote: 	
		   Mark;

  

 I tend to agree with Dennis on this one. Sure emough it was pilot error

 for not having the handle in  the down position. But to say it was 

 ENTIRELY pilot error is a stretch.


	


We do rather seem to want to lay blame here a lot. I winced when Mick

said he had the gear handle in the neutral position but I figured that

was pretty obvious and didn't need me to rub his face in it. I think it

is useful to know that it is possible to assemble the gear actuator lock

backwards and beating up on Mick seems a bit unnecessary.



If we beat up on everyone who admits to pilot error but provides

otherwise good information, eventually no one will ever provide information.



I have made plenty of errors when flying but have been lucky and never

bent an airplane. Errors you survive are fodder for training others to

avoid those errors.



-- 

Brian Lloyd                         2243 Cattle Dr.

brian-yak at lloyd dot com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

_________________
Brian Lloyd
brian-yak at lloyd dot com
+1.916.367.2131 (voice) +1.270.912.0788 (fax)

I fly because it releases my mind from the tyranny of petty things . . .
- Antoine de Saint-Exupery

viperdoc(at)mindspring.co
Guest

Posted: Fri Jan 20, 2006 10:30 am Post subject: Yak 52 r/h gear failure

Well said,

 Doc

  

 



  

 [quote] ---

viperdoc(at)mindspring.co
Guest

Posted: Fri Jan 20, 2006 10:33 am Post subject: Yak 52 r/h gear failure

Again, well said. That is what safety is all about...reviewing the mistakes

of others (yourself included) and hopefully not repeating them.

Doc

 	  Quote: 	
		   [Original Message]

 From: Brian Lloyd <brian-yak(at)lloyd.com>

 To: <yak-list(at)matronics.com>

 Date: 1/20/2006 12:05:31 PM

 Subject: Re: Yak 52 r/h gear failure

 Walter Lannon wrote:

 > Mark;

 >  

 > I tend to agree with Dennis on this one. Sure emough it was pilot error

 > for not having the handle in  the down position. But to say it was 

 > ENTIRELY pilot error is a stretch.

 We do rather seem to want to lay blame here a lot. I winced when Mick

 said he had the gear handle in the neutral position but I figured that

 was pretty obvious and didn't need me to rub his face in it. I think it

 is useful to know that it is possible to assemble the gear actuator lock

 backwards and beating up on Mick seems a bit unnecessary.

 If we beat up on everyone who admits to pilot error but provides

 otherwise good information, eventually no one will ever provide

information.

 	  Quote: 	

 I have made plenty of errors when flying but have been lucky and never

 bent an airplane. Errors you survive are fodder for training others to

 avoid those errors.

 -- 

 Brian Lloyd                         2243 Cattle Dr.

 brian-yak at lloyd dot com          Folsom, CA 95630

 +1.916.367.2131 (voice)             +1.270.912.0788 (fax)

 I fly because it releases my mind from the tyranny of petty things . . .

 - Antoine de Saint-Exupery

dsavarese(at)elmore.rr.co
Guest

Posted: Fri Jan 20, 2006 10:35 am Post subject: Yak 52 r/h gear failure

Agree 100% Walt.

 Dennis

  

 [quote]   ---

wlannon(at)cablerocket.co
Guest

Posted: Fri Jan 20, 2006 10:38 am Post subject: Yak 52 r/h gear failure

Brian;



I hope you are not suggesting I am beating up on Mick. I thought I made it 

quite clear in the last half of my post that was not the case.

You cut that part for brevity. Good idea but in this case maybe changed the 

message.



Cheers;

Walt

---

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Fri Jan 20, 2006 10:50 am Post subject: Yak 52 r/h gear failure

On second thought, if it is Roger we are beating up on then it is OK.



(Wink wink, nudge nudge)



Dogmatic: remember, we only hurt the ones we love. 



-- 

Brian Lloyd                         2243 Cattle Dr.

brian-yak at lloyd dot com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Fri Jan 20, 2006 10:59 am Post subject: Yak 52 r/h gear failure

Walter Lannon wrote:

 	  Quote: 	
		   

 

 Brian;

 

 I hope you are not suggesting I am beating up on Mick. I thought I made

 it quite clear in the last half of my post that was not the case.

 You cut that part for brevity. Good idea but in this case maybe changed

 the message.


	


Sorry, no. I apologize if it gave anyone that impression. I forget who

it was that made a more vociferous comment about it being pilot error

but felt the need to comment and yours was the only one lefts in this

thread when I replied.



I had originally cut it to just the first sentence but felt that would

have indeed implied that you were doing what I was complaining about and

that was definitely not the case.



Again, sorry if I gave the wrong impression. I thought your posting was

useful.



-- 

Brian Lloyd                         2243 Cattle Dr.

brian-yak at lloyd dot com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

Yakmech

Joined: 19 Jan 2006
Posts: 6
Location: Melbourne Australia

Posted: Fri Jan 20, 2006 11:52 am Post subject: Re: Yak 52 r/h gear failure

Thanks gents..

_________________
Once you have experienced flight you will forever walk this earth with your eyes turned skyward for it is there that you have been and there that you long to return !

viperdoc(at)mindspring.co
Guest

Posted: Fri Jan 20, 2006 4:09 pm Post subject: Yak 52 r/h gear failure

Yuk Yuk Yuk 

doc

 	  Quote: 	
		   [Original Message]

 From: Brian Lloyd <brian-yak(at)lloyd.com>

 To: <yak-list(at)matronics.com>

 Date: 1/20/2006 12:49:07 PM

 Subject: Re: Yak 52 r/h gear failure

 On second thought, if it is Roger we are beating up on then it is OK.

 (Wink wink, nudge nudge)

 Dogmatic: remember, we only hurt the ones we love. 

 -- 

 Brian Lloyd                         2243 Cattle Dr.

 brian-yak at lloyd dot com          Folsom, CA 95630

 +1.916.367.2131 (voice)             +1.270.912.0788 (fax)

 I fly because it releases my mind from the tyranny of petty things . . .

 - Antoine de Saint-Exupery

mark.j(at)yakuk.com
Guest

Posted: Sat Jan 21, 2006 3:10 am Post subject: Yak 52 r/h gear failure

I must apologise to Mick, thank you for sharing the information with the list, please continue to do so.  

   

I stand by my point it was pilot error. The pilot removed the pressure that held the leg in the down position, simple as that. An error. Why do this? Its not in any flight manual published by DOSAAF or the OEM that I have seen.   

   

Regarding the u/c ram. This a/c being a 1991 a/c if properly maintained has had its gear ram seals changed on 2 occasions by now. Remember these seals are 5 years life item.  The insurance company if it is looking to apportion blame is to refer to the maintenance company that signed for the changing of the seals on the last occasion, presumably they assembled the ram incorrectly.  

   

Further, the person/ company that did the last annual inspection is also implicated in the failure because he failed to do the inspection IAW manuals. Just to be clear here, when the a/c is on jacks every 50 hrs or 1 year and the u/c system is being internally lubricated, emg cycles/ retractions etc. the last check to do with air pressure neutral, Is to check that the  folding link will not break, ie checking to see that the locking balls in the ram have engaged. This is done by pushing hard at the centre of the folding link. Its very clear also that the maintenance company did not do this or they would have found the problem.   

   

As we know there are very few accidents where one item/ occurrence is the cause, its usually a chain of events.   

   

Regards, mj  

   

Ps, we all make mistakes, I put my hands up to a number, never get complacent.   

Pps I only take the digest so always 24 hrs behind the drag curve.

Yakmech

Joined: 19 Jan 2006
Posts: 6
Location: Melbourne Australia

Posted: Sat Jan 21, 2006 10:57 pm Post subject: Re: Yak 52 r/h gear failure

Mark.... Here in Australia we maintain aircraft such as the Yak52 as per the Regulatory guidelines, ie What our Civil Aviation Authority tells us we shall maintain an aircraft too.  These guidelines depend on several things, which I could obviously spend pages writing about if i needed too. But the requirements for the Yak here DO NOT require that the seals be changed every 5 years.. so... the rams have NOT been dissassembled since they came from the factory.  Further, the maintenance requirements DO NOT once again require the test that you suggest, which as I have already stated WOULD find the problem.  Now maybe the maintenance requirements for these sort of aircraft  should be looked at and further amended, BUT for you to ASSUME the maintenance company is at fault, is relying on the information that you have for the maintenance of the Aircraft in YOUR country.  And yes I do work for the maintenance company..... BUT...... I do not make the rules.... I only abide by them !!

Oh and yes I have already admitted that I made a mistake and I have no problem with admitting it.  If there was a problem with the maintenance and yes I am a part of that, do you think I would be posting it for all to see here ?????   Think about it.

_________________
Once you have experienced flight you will forever walk this earth with your eyes turned skyward for it is there that you have been and there that you long to return !

mark.j(at)yakuk.com
Guest

Posted: Mon Jan 23, 2006 12:14 am Post subject: Yak 52 r/h gear failure

Mike, I assume the YAK 52 is operated on the experimental or limited register is AU hence you don't take any notice of the OEM that had a massive design team and knowledge base from experience of the materials and equipment. If was from this knowledge base that operating procedures were drawn up. These obviously have factors of safety included.   

   

Its been mentioned on the list in the past the amount of rust found in these items (u/c lifters) along with resultant seals leaking. This surely would have given you a heads up to investigate the rams/ lifters after 15 years!! Rather than wait for a failure as seams to be the norm.  

   

I'm pretty sure CASA does not have anyone in the “company” that worked at YDB to pass along the knowledge so its down to the maintenance companies and owners to act in a responsible manner and maintain a/c IAW manuals and common sense (ie checking the leg locks!!)   

   

We (world wide) are permitted to operate these experimental a/c (remember the wording “This a/c is not certificated to an international standard”)  and its our responsibility to operate as safely as possible or suffer the consequences of tightened CASA, FAA, CAA etc regulations not to mention litigation.   

   

So, basically I implore you to read all the manuals and recognise the OEM requirements as I have said they know far more than you and I on the matter.  Why put your own safety and that of potentially many others at RISK because YOU/ Owner wanted to save a few bucks? (by skipping maintenance)  Lastly litigation would follow when someone was hurt through the negligence of lack of maintenance that’s for sure.  

   

As a foot note I thought the limited register that allowed public transport flights in AU in non certified a/c says that life items must be adhered to.  One of my customers there certainly adheres to the OEM requirements for that reason.   

   

           

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"Yakmech"   <mjpoole(at)hunterlink.net.au (mjpoole(at)hunterlink.net.au)>         	  Quote: 	
		              --> Yak-List message posted by: "Yakmech" <mjpoole(at)hunterlink.net.au>            Mark.... Here in Australia we maintain aircraft such as the Yak52 as per the Regulatory      guidelines, ie What our Civil Aviation Authority tells us we shall maintain      an aircraft too.  These guidelines depend on several things, which I could      obviously spend pages writing about if i needed too. But the requirements      for the Yak here DO NOT require that the seals be changed every 5 years.. so...  	
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Yakmech

Joined: 19 Jan 2006
Posts: 6
Location: Melbourne Australia

Posted: Mon Jan 23, 2006 3:17 am Post subject: Re: Yak 52 r/h gear failure

Since this incident I have been very concious of the fact that there is alot to know and learn, I for one will never say that i know everything because I learn something every day. 



I still say that in this case the maintenance was sufficent for the information available.  Although the aircraft is approaching 15 years old, the flight and maintenance history of this aircraft is very well known.  Remember it only has 32 hours total time.  Its because of this fact and knowing what the aeroplane has done,, or rather has not done that makes me believe that all that could have been done, was done to the best of our knowledge.



  I have seen rusted yak systems etc before, so I know what it does and potentially what it can cause.  There was no need or concern for this aircraft with regards to this sort of problem, even though it is approaching 15 years and hence no nead to pull the rams out and disassemble them. I am not interested in saving money for the customer if safety is a factor. 

Im not interested in being that "cheap bloke" down the road for aircraft maintenance, im more interested in seeing the aeroplane perform as it should between services without the customer having to come back for unsheduled maintenance.



Unfortunately most of the time maintenance practices only change when there is an accident or incident or better and further information is available.   In this case I / We now have both.  In my case my personal practices both in the hangar and in the air will change from this incident, all be it a hard way to learn.  But once again the reason for my post...the more that know the less likely that its going to happen again. 



 You can never know to much or have to much information when the safety of others is  in your hands.  The more I can pass on as a result of this incident and the more I can learn personaly can only be of benefit surely.  



So rather than can me or any other person / organisation trying to pass on information for others to learn from, maybe, as you have started  doing in your later posts, pass on the information and not can a bloke for trying to do the right thing wether he be the pilot or mechanic.



I will take on board the relevant and useful information that you have provided and I appreciate that.... BUT I will not stand by and be critisised personaly by anyone who does not know the full facts about the incident, the aeroplane or the maintenance practices if they realy have no idea what is going on in the first place. Remember..... dont ASSUME anything or you will make an ASS out of U and ME.



I am willing and ready to learn and know as much as possible about the aeroplanes that I fly and work on. Anyone that is willing to pass on that information in a reasonable and constructive manner I am willing to listen too.



Mick

_________________
Once you have experienced flight you will forever walk this earth with your eyes turned skyward for it is there that you have been and there that you long to return !

gus.fraser(at)gs.com
Guest

Posted: Mon Jan 23, 2006 6:01 am Post subject: Yak 52 r/h gear failure

Mark raises what is almost the single most serious point with ongoing

maintenance of these aircraft, regardless of country of origin. That is the

issue of lifed items.



Now how many of you out there are riding around fat dumb and stupid with

seals over 5 years old, fuel lines that have exceeded useful life. These

aircraft have a considerable list of items that need to be changed on spec,

how many of you are doing that ?



Mark can you post a list of lifed items for Yak aircraft as I think it will

shock some subscribers. As Mark mentions it will not take long for insurance

companies to see this as an out if you don't get this stuff replaced. But as

always it is up to you if you know about it and choose to avoid it don't

complain when the insurance company says bye bye.



Personally I think this is probably the biggest safety risk to the US fleet

right now and I am sure that we will see a few more issue sin this space in

the future. As far as fuel lines go, for example, it cost very little to

have them replaced, a lot more than the cost and pain associated with an in

flight fire.



I would urge you to also look at the information that Mark put together

about Yak 52 bulletins at http://www.yakuk.com/MPD.asp 



Gus



--

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