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eranzenbach

Nose Gear Collapse

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I'm the proud owner of N16AV, long EZ built by Kent Ashton. Kent is truly a master builder, and finished the plane in 2014. I recently purchased it from him and he was kind enough to fly it out to southern California from North Carolina. He also spent a few days out here transitioning me into the aircraft. During my transition I found the aircraft to be a little hotter than the Cessna 172 that I trained and certified in. Several of my initial landing attempts, well let's just say I stressed the gear. I also know that I bounced the nose gear up and down off the runway numerous times in my first 30 landings and I suspect this to be the cause of my nose gear collapse (See https://www.youtube.com/watch?v=KGRVgcN0_kg for GoPro video from inside the cockpit).

 

After spending the afternoon with an FAA accident investigator, it appears that the strut itself or the NG3 bracket failed. During the incident, I also picked up some kind of foreign object and put a small nick in the propeller blade. Ground services at my airport were kind enough to tow me in, however during the tow, the nose strap came loose and the airplane tipped backwards, fortunately not on the propeller, but there is some minor damage to the wheel pants and the rudders.

 

Having never built an airplane for, I look forward to making the repairs and making aircraft my own. Kent has been kind enough to take a look at pictures of the damage and, I'm sure, the mentoring me through the process. I'm also hoping to enlist the help of several local members of the EAA as I put the airplane back into flight condition. I intend to document process so that other newbies like myself can appreciate the design durability of this aircraft and ability to put it back into flying condition after an accident.

 

My first step will be to do a detailed inspection of the damage the aircraft. That will be my next couple of postings. I will post pictures of the damage and the fixes as it's repaired.

 

 

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Posted (edited)

Oh, my baby! :-)

 

i think the most work will be to repair the wheel pants. The upper part around the strut can be fixed (maybe) by forcing wet flox in the crack and clamping it tight until cure. The lower aft part could use a patch. Where the mount tore out of the inboard surface, you might cut the bad piece out and put a 3 or 4 layer patch inside and 2 or 3 layers outside. Pants always take a beating anyway. You could install new ones but it’ll likely be a lot less work to patch those.

 

I just talked to Jon. Sounds you will get it flying again pretty fast. If you send me the exact width and thickness of the strut at the NG3 position, I’ll make you some steel NG3s.

 

BTW, those airplane movers didn't do you any favors. Doubled your damage, I’d guess. Be very cautious about letting FBO folks move your plane. They don’t know about the tipback potential.

Edited by Kent Ashton

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Kent,

 

Thanks as always for the sage advice. I tried to get them to let me ride in the cockpit while they were towing it in, but they refused. It's my fault really, I should have tied the nose down to the tow brace myself.

 

As I've already emailed you, I've found a local source that can machine new parts, the NG3, and the 10A rod. The spar itself looks like it's in good condition. I've also inspected the main landing gear spar as you've suggested. It looks to be fine. No small cracks that I can see, nothing flaking off of it, nothing to indicate that it sustained any damage. This is a credit to your decision to use the more robust Cozy gear on this Long EZ.

 

The gentleman doing the machining of the new parts is Jim Emons. Jim's specialty is converting manual to electric retractable gear on long EZ's and Cozy's. Jim comes recommended through EAA chapter 96 in Compton California and he lives near Chino California. His email address is jeezuni61ze@gmail.com and I'm sure he can be a source for parts if anyone needs anything.

 

An FAA accident investigator came out and took several pictures and has concluded that the bushing rod end where it connects to NG3 failed. I've included pictures of the failed NG3 bracket showing the bushing rod end connection that fractured. Also included is a picture of the 10A rod itself, which ground down against the pavement and will have to be replaced as well. After that it's just a matter of getting glasswork done. Hopefully I'll be back in the air this coming weekend.

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An FAA accident investigator came out and took several pictures and has concluded that the bushing rod end where it connects to NG3 failed.

 

Well, yeah, but that's not the root cause of the failure.

 

A rod-end failing would not cause NG-3 and NG-4 to rip off of the nose gear strut. He's got it backwards - your apparently AL NG-3 and NG-4 (which both should have been 4130 steel per page 13-3 of the LE plans, NOT aluminum) bent and collapsed due to one or more hard landings (you can see that the bolt that goes through the NG-3/NG-4 and rod end, with the spacers on it, also bent from the impact) and when the NG-3/NG-4 substandard pieces bent/failed and ripped off the gear strut, the rod end THEN broke due to a side load. The rod-end cannot have a side load, even from enormously bad landings, due to geometry unless the NG-3/NG-4 have already deformed in a major manner.

 

Having someone who knows little to nothing about the aircraft in question try to perform a forensic analyses is nigh on useless. I'm sure the FAA doesn't give a crap about the root cause of this failure, since it was neither an accident nor possibly even an incident, but you could fill them in on the actual analysis presented here if you want or if they ask.

 

I've included pictures of the failed NG3 bracket showing the bushing rod end connection that fractured. Also included is a picture of the 10A rod itself, which ground down against the pavement and will have to be replaced as well. After that it's just a matter of getting glasswork done. Hopefully I'll be back in the air this coming weekend.

 

Good luck on the repairs - you're lucky there wasn't substantially more damage. Emons should be able to make the parts you need. Ask him about belleville washers for the prop, while you're at it, if you want a fireworks show :-).

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Marc,
 
Thanks for the insight. You are correct, I had several hard landings with Kent in the backseat. Although I didn't say in my initial post that I had hard landings, I did say that I stressed the gear.
 
The new parts will be made of steel. Once I get it back together, I'll give you call and make arrangements to have an inspection done.

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 your apparently AL NG-3 and NG-4 (which both should have been 4130 steel per page 13-3 of the LE plans, NOT aluminum)

 

 

Good catch Marc.  I built the EZ strut using Cozy plans and did not notice the Long-EZ steel spec; it is not specified in the Cozy plans anywhere that I can find.  My Cozy brackets are aluminum too.  Must change them out.

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Good catch Marc.  I built the EZ strut using Cozy plans and did not notice the Long-EZ steel spec; it is not specified in the Cozy plans anywhere that I can find.  My Cozy brackets are aluminum too.  Must change them out.

 

Interesting - I bought mine from Brock (Wilhelmson sell them now) and they're steel. But you're right, the COZY MKIV plans don't call out the material (assuming, I suppose, that you'll buy them from the approved supplier). See:

 

http://www.eznoselift.com/index.php/price-list

 

I can't imagine why Nat would have removed that piece of information from the plans - who was it hurting or confusing?

 

But yes - if I were you, I'd install steel versions on your COZY, just in case... AL is only 1/3 the stiffness - hence the buckling of the sides under stress. And I'd do it before the next flight.

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Posted (edited)

Repairs going well. Received the new parts from Jim Emmons on Friday. The new NG4 and NG3 are steel.

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Edited by eranzenbach

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Did layups and clamped in place for 48 hours. Also used JB Weld to repair small chip and scrapes out of prop. After curing for 48 hours and sanding, applied primer. 

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Rich Schleicher from EAA Chapter 96, and himself a Long EZ owner with experience rebuilding the nose stopped in and looked over the repairs to date. Flocked NG3/NG4 and let cure for 48 hours. Cut out damaged skin with Dremel tool and used micro-spheres to fill in damage to underside of nose. Had to hold up micro-spheres with a strip of duct tape until cured. Then sanded micro-spheres and skin around cut-out and then applied several layups of BID.

 

Question: Do I need to use BID over the strut, on either side of NG4?

 

I should now be able to drill and connect the gear and proceed with repairing the gear door.

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Question: Do I need to use BID over the strut, on either side of NG4?

 

Ed, I used some BID over the NC4 to increase the security of the NG4/3 with the strut but it is not called for in the plans.  

 

As for fixing the strut door/cover, it looks like you could work the strut cover off the strut, sand away the 90 degree layups that attached it to the strut (pic), and reuse the flat cover with new attach layups.   That sounds easier to me than trying to make a new cover.  Alternatively, you might be able to clean up the cover as-is and flox it back on the strut.  That'd probably work, too.

 

The prop looks pretty good but it probably needs balancing again.

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Did layups and clamped in place for 48 hours. Also used JB Weld to repair small chip and scrapes out of prop. After curing for 48 hours and sanding, applied primer. 

Why not take this opportunity to convert to an electric lift?

Definitely have someone shoot the prop with a micro-vibe!

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Definitely have someone shoot the prop with a micro-vibe!

 

I am not poo-pooing the dynamic balancing thing but the little hanging balance I made here worked like a champ and could be adjusted to measure a Nat's ass [get it?  :-)].  Much better than rolling the prop on a shaft because it takes into account lateral imbalance in the hub and blades.

http://www.canardzone.com/forum/topic/18661-kents-long-ez-project/?p=60194

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