Nosegear Leg Replacement

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Steve
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Re: Fuel selector valve universal joint replacement

Post by Steve »

Davestation wrote: Thu Feb 06, 2020 4:48 am I'm all for replacing something that you know will inevitably break anyway, kind of like the nose gear leg although in this case way less expensive - which rules out the only potential con
As far as I recall, only one nosegear leg developed a crack and failed, and that aircraft was operated almost entirely on rough fields. I haven't heard of another crack being discovered by the 200 hour dye penetrant inspection (which my aircraft is due for this annual). The way I, and the vast majority of DA40 operators fly I think it is highly unlikely that another crack will ever be found in the original design nosegear legs that remain in service.

But, the inspection is cheap and easy, so I don't want to spend $5K for a new gear leg to solve a problem which doesn't really exist...

Steve
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Re: Fuel selector valve universal joint replacement

Post by Rich »

Steve wrote: Thu Feb 06, 2020 2:22 pm
As far as I recall, only one nosegear leg developed a crack and failed, and that aircraft was operated almost entirely on rough fields.
May have just happened to a DA20 last week.
https://aviation-safety.net/wikibase/232689
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Re: Fuel selector valve universal joint replacement

Post by Davestation »

Steve wrote: Thu Feb 06, 2020 2:22 pm
Davestation wrote: Thu Feb 06, 2020 4:48 am I'm all for replacing something that you know will inevitably break anyway, kind of like the nose gear leg although in this case way less expensive - which rules out the only potential con
As far as I recall, only one nosegear leg developed a crack and failed, and that aircraft was operated almost entirely on rough fields. I haven't heard of another crack being discovered by the 200 hour dye penetrant inspection (which my aircraft is due for this annual). The way I, and the vast majority of DA40 operators fly I think it is highly unlikely that another crack will ever be found in the original design nosegear legs that remain in service.

But, the inspection is cheap and easy, so I don't want to spend $5K for a new gear leg to solve a problem which doesn't really exist...

Steve

I’ve replaced at least five that were cracked, a couple almost the entire circumference. They were all operated on good runways, although most were flight school aircraft...
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Re: Fuel selector valve universal joint replacement

Post by Steve »

Davestation wrote: Thu Feb 06, 2020 5:12 pm
Steve wrote: Thu Feb 06, 2020 2:22 pm
Davestation wrote: Thu Feb 06, 2020 4:48 am I'm all for replacing something that you know will inevitably break anyway, kind of like the nose gear leg although in this case way less expensive - which rules out the only potential con
As far as I recall, only one nosegear leg developed a crack and failed, and that aircraft was operated almost entirely on rough fields. I haven't heard of another crack being discovered by the 200 hour dye penetrant inspection (which my aircraft is due for this annual). The way I, and the vast majority of DA40 operators fly I think it is highly unlikely that another crack will ever be found in the original design nosegear legs that remain in service.

But, the inspection is cheap and easy, so I don't want to spend $5K for a new gear leg to solve a problem which doesn't really exist...

Steve

I’ve replaced at least five that were cracked, a couple almost the entire circumference. They were all operated on good runways, although most were flight school aircraft...
Wow, that is interesting. Searching the FAA SDR database doesn't return any reports of a failure. I'm not certain, but the one event cited in the original SB may have been outside the USA.
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Re: Fuel selector valve universal joint replacement

Post by Rich »

Rich wrote: Thu Feb 06, 2020 2:30 pm
Steve wrote: Thu Feb 06, 2020 2:22 pm
As far as I recall, only one nosegear leg developed a crack and failed, and that aircraft was operated almost entirely on rough fields.
May have just happened to a DA20 last week.
https://aviation-safety.net/wikibase/232689
Hard to tell exactly what failed. Maybe the nut or the threaded portion:
DA20 NoseGear problem.jpg
Last edited by Rich on Sat Feb 08, 2020 2:35 am, edited 1 time in total.
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Re: Fuel selector valve universal joint replacement

Post by Davestation »

Steve wrote: Thu Feb 06, 2020 11:22 pm
Wow, that is interesting. Searching the FAA SDR database doesn't return any reports of a failure. I'm not certain, but the one event cited in the original SB may have been outside the USA.
It seems silly to submit a SDR for a known issue.
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Re: Fuel selector valve universal joint replacement

Post by Davestation »

Rich wrote: Sat Feb 08, 2020 1:04 am
Rich wrote: Thu Feb 06, 2020 2:30 pm
Steve wrote: Thu Feb 06, 2020 2:22 pm
As far as I recall, only one nosegear leg developed a crack and failed, and that aircraft was operated almost entirely on rough fields.
May have just happened to a DA20 last week.
https://aviation-safety.net/wikibase/232689
Hard to tall exactly what failed. Maybe the nut or the threaded portion:

DA20 NoseGear problem.jpg

Definitely the nut in that case. Someone called me once asking if we change the nut each time and of course I said “yeahwhyyyy?”
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Re: Fuel selector valve universal joint replacement

Post by Steve »

Rich wrote: Sat Feb 08, 2020 1:04 am
Rich wrote: Thu Feb 06, 2020 2:30 pm
Steve wrote: Thu Feb 06, 2020 2:22 pm
As far as I recall, only one nosegear leg developed a crack and failed, and that aircraft was operated almost entirely on rough fields.
May have just happened to a DA20 last week.
https://aviation-safety.net/wikibase/232689
Hard to tall exactly what failed. Maybe the nut or the threaded portion:

DA20 NoseGear problem.jpg
The failure point on the DA40 gear was at the junction of the machined bearing surface and the leg. Diagram from the Service Bulletin:
Nosegear.jpg
Nosegear.jpg (19.81 KiB) Viewed 2179 times
From the photo that Rich posted, that area of the nosegear is intact. At the resolution of the image it isn't possible to determine if the threaded portion broke, or if the nut was lost.
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Re: Fuel selector valve universal joint replacement

Post by Steve »

Davestation wrote: Sat Feb 08, 2020 1:11 am
Steve wrote: Thu Feb 06, 2020 11:22 pm
Wow, that is interesting. Searching the FAA SDR database doesn't return any reports of a failure. I'm not certain, but the one event cited in the original SB may have been outside the USA.
It seems silly to submit a SDR for a known issue.
SDRs are not only to "discover" an issue, but also to determine how frequently it occurs, and sometimes even to help limit the issue to a certain date range of parts manufacture, or a certain manufacturer. In this case, the Service Bulletin was issued for a single occurrence. If it is more common (as you stated from your experience) further action (AD) might be considered. I never heard about your 5 failures...

Steve

Maybe we should change the title of this thread to Nosegear Replacement... ;)
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Re: Fuel selector valve universal joint replacement

Post by Davestation »

Steve wrote: Sat Feb 08, 2020 3:04 am If it is more common (as you stated from your experience) further action (AD) might be considered. I never heard about your 5 failures...
It’s already an AD...

Sorry, I was trying to use a relatable parallel and accidentally hijacked the entire thread.
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