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Whoops - loss of flap pin

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graeme bird

Joined: 15 Jul 2010
Posts: 434

Posted: Sat Oct 15, 2016 10:11 am Post subject: Whoops - loss of flap pin

Interesting flight back from Sandown UK this afternoon. It seems I lost a flap pin somewhere (into the tube I think). On takeoff from a bumpy field had a sudden strong port wing down tendency. I assumed the flaps were different and wondered if the mono port wing leg had collapsed. But,  I was in the air and when retracted seemed fairly normal. On arrival back at my base strip I tried a few things at altitude and a couple of simulated approaches. It seemed just about controllable if into wind. So I landed in a square field at the end of our narrow strip so it could skew around if required. Phew, all ok, the leg did collapse and it skewed slightly in the last few yards but no grass contact with the prop and no damage to the wing end. I assume that the pin wasn't well locked in and had ratcheted out on repeated use. The tube still controlled the flap but it could move about an extra few degrees and no longer could be extended enough to lock the leg down. Perhaps some big G movement might have flicked it. Keeping that pin lubricated better might be a good idea and some loctite on the threads.

_________________
Graeme Bird
kit4 (Wagstaff) TBD
Kit3 G-CLXU (Gregory) mono 914 xs Woodcomp
Kit2 G-PATS - (kesterton) Mono Classic 912 warpdrive
Kit 1 G-UMPY - Mono Classic/XS 912S, Woodcomp G(@)gdbmk.co.uk

brian.davies(at)clara.co.
Guest

Posted: Sun Oct 16, 2016 1:53 am Post subject: Whoops - loss of flap pin

Hi Graeme,



I am glad that you got down safely.  I assume you are referring to the pin

screwed into the root of the flap and that you have confirmed that it is

missing.  Are you able to confirm that it came unscrewed rather than sheared

off?  Although this all ended safely the failure of this pin is a pretty

serious event and it is worth sharing the details so please let Malcolm

McBride or Andy Draper of the LAA know the results of your investigation.



Best regards



Brian Davies



--

spcialeffects

Joined: 29 Aug 2012
Posts: 306
Location: Kent

Posted: Sun Oct 16, 2016 2:41 am Post subject: Re: Whoops - loss of flap pin

Hi Graeme, these pins at time of fitting should have been loctited into place. I think you bought the kit part built didn't you? did you build the flaps?



Regards Frank Kit 165

brian.davies(at)clara.co.
Guest

Posted: Sun Oct 16, 2016 7:12 am Post subject: Whoops - loss of flap pin

Message from Pete Jeffers:



Brian I have difficulty sending to the forum when in the US so request you

read and forward this to the forum when you receive it.



Hi Brian and all,

As a Europa Inspector for the LAA for many years I do have to report that I

have found at least two other wing/flap screwed and locktited pins to be not

tight. ie I have managed to unscrew them with my fingers only. In the past I

have treated these instances as one offs but this event with G-UMPY

highlights the possible need for a mandatory or MPD to cover this issue.  I

do highlight that I have found loose not only the flap drive pin but also

the main leading and trailing edge pins.

Pete Jeffers



--

Richard Wheelwright

Joined: 15 Sep 2008
Posts: 111
Location: Halifax, West Yorkshire, UK

Posted: Sun Oct 16, 2016 7:31 am Post subject: Whoops - loss of flap pin

If I recall the pins should be screwed in with neat redux (420 A&B) on the XS wings. May be this is an update in the manual from the classic build? The only way you could get the pins out on my aircraft is to heat the pins. But it is with raising this and need to be checked. If it is broken off more investigation is needed. 



Regards



Richard Wheelwright



[quote] On 16 Oct 2016, at 16:12, Brian Davies <brian.davies(at)clara.co.uk> wrote:

 

 

 

 Message from Pete Jeffers:

 

 Brian I have difficulty sending to the forum when in the US so request you

 read and forward this to the forum when you receive it.

 

 

 

 Hi Brian and all,

 As a Europa Inspector for the LAA for many years I do have to report that I

 have found at least two other wing/flap screwed and locktited pins to be not

 tight. ie I have managed to unscrew them with my fingers only. In the past I

 have treated these instances as one offs but this event with G-UMPY

 highlights the possible need for a mandatory or MPD to cover this issue.  I

 do highlight that I have found loose not only the flap drive pin but also

 the main leading and trailing edge pins.

 Pete Jeffers

 

 --

_________________
Richard Wheelwright
G-IRPW
First Flight 24th July 2013

fireflier

Joined: 24 Jun 2012
Posts: 59

Posted: Sun Oct 16, 2016 7:34 am Post subject: Whoops - loss of flap pin

Hi All



I notice that people are making reference to loctiting the wing pin/flap pins into place.  My understanding and reference to the manual chapter 26 page 3 these pins have to be secured using a small quantity of araldite 420 on the pin threads and also the threads in the hole.  



This is something that should become a regular maintenance check item, as the consequence of loosing these pins could have resulted in a completely different outcome. 



Kind regards

Donald

G-PUPY

Sent from my iPhone



[quote] On 16 Oct 2016, at 16:12, Brian Davies <brian.davies(at)clara.co.uk> wrote:

 

 

 

 Message from Pete Jeffers:

 

 Brian I have difficulty sending to the forum when in the US so request you

 read and forward this to the forum when you receive it.

 

 

 

 Hi Brian and all,

 As a Europa Inspector for the LAA for many years I do have to report that I

 have found at least two other wing/flap screwed and locktited pins to be not

 tight. ie I have managed to unscrew them with my fingers only. In the past I

 have treated these instances as one offs but this event with G-UMPY

 highlights the possible need for a mandatory or MPD to cover this issue.  I

 do highlight that I have found loose not only the flap drive pin but also

 the main leading and trailing edge pins.

 Pete Jeffers

 

 --

_________________
Fireflier

dg.watts(at)talktalk.net
Guest

Posted: Sun Oct 16, 2016 7:45 am Post subject: Whoops - loss of flap pin

Hi All,



Personally I put reasonable force into testing these all pins at each annual, as their inspection is called for in the Europa Annual Checklist and I also do likewise at each 50 hour service/inspection.



Dave Watts

G-BXDY Classic Monowheel 2,300 hours



[quote] On 16 Oct 2016, at 16:12, Brian Davies <brian.davies(at)clara.co.uk> wrote:

 

 

 

 Message from Pete Jeffers:

 

 Brian I have difficulty sending to the forum when in the US so request you

 read and forward this to the forum when you receive it.

 

 

 

 Hi Brian and all,

 As a Europa Inspector for the LAA for many years I do have to report that I

 have found at least two other wing/flap screwed and locktited pins to be not

 tight. ie I have managed to unscrew them with my fingers only. In the past I

 have treated these instances as one offs but this event with G-UMPY

 highlights the possible need for a mandatory or MPD to cover this issue.  I

 do highlight that I have found loose not only the flap drive pin but also

 the main leading and trailing edge pins.

 Pete Jeffers

 

 --

graeme bird

Joined: 15 Jul 2010
Posts: 434

Posted: Sun Oct 16, 2016 11:28 am Post subject: Re: Whoops - loss of flap pin

it didn't shear off. As the flap moves through an angle there is a turning moment on this one. This is not true of the other pins. The rear wing pin has a nut on the back and a pin through it. I haven't checked starboard flap pin yet. It maybe that the turning tends to tighten that side and loosen the Port. And it maybe that due to alignment perhaps there was some pressure on it.

I can only assume that in this case redux was omitted or sparse.  I cant recall if the socket it goes is a bearing and whether lubrication should have been regularly applied. The other pins are greased.

Roland

Joined: 30 Nov 2009
Posts: 334
Location: EDLE

Posted: Mon Oct 17, 2016 12:17 am Post subject: Re: Whoops - loss of flap pin

Graeme,



many thanks for sharing this. Although mine is an XS, I will check the pins thoroughly more often since I trailer my Europa to the airfield and so have access to them. 

 

Regards 

Roland

PH-ZTI

XS TG 914

kingsnjan(at)westnet.com.
Guest

Posted: Mon Oct 17, 2016 1:34 am Post subject: Whoops - loss of flap pin

Graeme,



I fail to see how there is any turning moment on the flap drive pin. Both the flap and the flap cross tube pivot around a common axis. 



However, because of the wings dihedral, if the floating bearing in the end of the flap cross tube is seized or very tight, this may possibly induce some turning moment especially if the bearing surface of the pin inside the bearing was not lubricated. 



Personally, I hope there is no knee jerk reaction to this failure resulting in a mandatory mod.  My flap drive pins were reduxed in and if the problem I had getting my rear wing pins out for that mod are any example, there is no way my flap drive pins are ever going to back out of their own accord. 



Best Regards

Kingsley in Oz



Sent from my iPhone



 	  Quote: 	
		   On 17 Oct. 2016, at 5:28 am, graeme bird <graeme(at)gdbmk.co.uk> wrote:

 

 

 

 it didn't shear off. As the flap moves through an angle there is a turning moment on this one. This is not true of the other pins. The rear wing pin has a nut on the back and a pin through it. I haven't checked starboard flap pin yet. It maybe that the turning tends to tighten that side and loosen the Port. And it maybe that due to alignment perhaps there was some pressure on it.

 I can only assume that in this case redux was omitted or sparse.  I cant recall if the socket it goes is a bearing and whether lubrication should have been regularly applied. The other pins are greased.

 

 --------

 Graeme Bird

 G-UMPY -  Mono Classic/XS FFW 912S, Woodcomp 3000/3W CS, trutrak Gemini 2 axis ap, pflarm, ads-b out, 8.33khz, mode S, FP 5, Aera500 &amp; SD on Nexus,

 250 hours &amp; 4 years on the Mono, 880 total

 g(at)gdbmk.co.uk

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=461350#461350

graeme bird

Joined: 15 Jul 2010
Posts: 434

Posted: Mon Oct 17, 2016 9:03 am Post subject: Re: Whoops - loss of flap pin

I can now confirm it was a build issue and not a design problem. The starboard pin was fully in and had not moved, but not glued in. I shall also be checking these regularly now and will also keeping lubricated along with the bearing.

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