HD Extended Gear Failure Report

[RamBuster]

Howdy Husky Brain Trust,

Passing along a recent event and details regarding a failure I have had on a set of extended seaplanes north HD gear. Purchased in August of 2022, have been extremely happy with them up to this point. I run a '90 A1 in the NWT of Canada completely off airport and this gear has been nothing but excellent.

However, last week while operating on skis I noticed a significant crack where the camber strut meets the shock absorber section of the gear. Upon further inspection (as pictured in the attached), I discovered that this portion of the gear was also significantly bent on the one side. We were able to make it home, and upon removal of the gear the damage appeared to be due to rebound forces. I was running the super SGS, with 1x1380HD and 2x1280CW as per Thomas's recommendations, on 31's ABW & M2000 skis. The was no indication of any other damage to the skis or weld points on the gear, and no impact (hard landing) event that I could note in the 150hrs since install.

Jeff at Seaplanes and Atlee Dodge have been great to deal with on this, but they did note that several sets of the extended HD gear have had individual failure at the same point that are not from an obvious cause. At this time they are not fabing any new extended gear until they can revisit the design and determine what the fix may be. I am getting set up with a set of stock length HD gear from atlee, that have not seen the same pattern of failures, and hopefully back airborne in about a months time.

Personally, I think a contributing cause may have been the lighter bungee combination, creating more travel as the gear rebounds from compression, but based on the report from the manufacturer it does seem to be a trend. Will be upgrading to 1380HDs all around on the next set. Any other thoughts on the below would be appreciated, this forum has been fantastic for learning more about the Husky!

Cheers,

Rambuster

 

[GreggMotonaga]

Sorry to hear that. I use the standard length HD gear legs from Atlee because the Airglas GLH 3000 skis are not approved on the extended length gear. There may be a good reason for that.

 

[belloypilot]

Ouch. Glad you made it home safely. To my untrained eye it looks like it might be a side load on the ski pushing in the inboard direction. Does that make sense? Perhaps a combination of a side load simultaneous with the bungees extended a bit?

 

[RamBuster]

@belloypilot

I would suspect you could be right. I'll be the first to admit that my loading force meter in my gear is inoperable, so a heavy turn on skis in crusty snow could also be an answer. Glad to avoid something more serious and should still be able to make the Muncho fly in this year!

 

[belloypilot]

If it was an issue with sideloads, I wonder if more curvature to the edges of skis would reduce the risk a bit. Don’t mistake my musings for me knowing what I’m talking about. I have a neighbor who folded up a gear leg on his Bushmaster when landing at his farm strip on skis. I think he’d ‘groomed’ it so it was a hard packed surface. He suspects he caught a rut and it abruptly collapsed. Luckily no prop strike, and it was on his home field so about as ‘convenient’ as a mishap like that can get.

Wish I could make it to Muncho this year but not looking like it. It’s always a fun gathering in a great location.

 

[Alaska]

Thank you for your post. Nice to hear they are finally admitting there's a problem with the gear. Wish I got off as lucky as you, my gear failure cost me a lot more.
I believe the gear leg failed at the welds, the inner added structural tubes end before the weld. The added length is adding leverage and causing strain on the welds.
I flew my stock gear for 13 years with many landings, nothing like this had ever happened. This gear did not last one season. I was told there were no other issues like mine at that time, and it was my own fault. I would say if you are flying this gear you should be very careful.

(August 2022)

 

[tbienz]

Disturbing to read this as I purchased the extended HD gear because I wanted it to be stronger since I was putting RF skis on the plane. Possibly a reason to leave the gear unfaired so that you can inspect it. That much said, I've had my set for a long time running 31's in the summer and skis in the winter and so far no issues. I'm assuming if this is a trend they will eventually issue an AD?

 

[Larson]

Disturbing to read this as I purchased the extended HD gear because I wanted it to be stronger since I was putting RF skis on the plane. Possibly a reason to leave the gear unfaired so that you can inspect it. That much said, I've had my set for a long time running 31's in the summer and skis in the winter and so far no issues. I'm assuming if this is a trend they will eventually issue an AD?

Hi Thomas, I am in the same boat as you. I purchased for extra strength and use 31‘s only on them, amphibs other times.
I have no fairings and will keep a good eye on mine, but can’t say I’m comfortable going forward?? … I would like further information..

 

[Snowbirdxx]

We had the Seaplane gear on for 4 month. One hard landing resulted in a catastrophic gear failiure,. We had to helicopter the plane out. Jeff at Seaplanes North is a nice guy, but said that there is no warranty on gears at all. Questions about the welds were not answered. No skis on that gear,850 tires.. Looking at the geard geometry and design, there are many open questions. 29 years on the Aviat gear with many hard landings always resulted in bent maingear bolts. A 4$ item.

 

[Alaska]

We had the Seaplane gear on for 4 month. One hard landing resulted in a catastrophic gear failiure,. We had to helicopter the plane out. Jeff at Seaplanes North is a nice guy, but said that there is no warranty on gears at all. Questions about the welds were not answered. No skis on that gear,850 tires.. Looking at the geard geometry and design, there are many open questions. 29 years on the Aviat gear with many hard landings always resulted in bent maingear bolts. A 4$ item. View attachment 6903 View attachment 6904 View attachment 6905 View attachment 6906 View attachment 6907

Sorry to hear you have had the same thing happen. I have gone back to my original gear since August of 2022.
When did your incident happen?

 

[Oryx]

It may be extended but it sure doesn’t seem like HD gear!

 

[Snowbirdxx]

Sorry to hear you have had the same thing happen. I have gone back to my original gear since August of 2022.
When did your incident happen?

Installed spring 23, collapse Oct 23 after 1520 landings, most of them on grassfields.

 

[GreggMotonaga]

Installed spring 23, collapse Oct 23 after 1520 landings, most of them on grassfields.

1520 landings in 6 months? WOW. That might take me 5 years.

 

[Clifford]

Side note to this subject:
Looking at the pics of failed gear it looks like some or all are powder coated. Everyone that knows me knows powder coating is one of my pet-peeves. In my view nothing structural should ever be powder coated: it makes cracks difficult or impossible to see as they develop. Plain urethane if you must; electroless nickel plating is my preferred.

 

[groshel]

I’d be inclined to agree with you on powder coating hiding developing cracks but these pictures are showing very clean cracks with no evidence of rust which would indicate pre failure cracking. Maybe a in person visual inspection would prove otherwise

What’s even more astonishing is the cracks propagated right though those wrap-around, arrowhead shaped doublers at the end of the tubes.I can’t imagine what loads existed to do this damage!

c

 

[tbienz]

As many of you with this gear are probably already aware, the manufacturer is reaching out to owners asking them to do an immediate inspection before further flight.
When I spoke with them on Thursday, he indicated that unfortunately, is is highly likely that I will need to remove my gear and send it to Seaplanes North (SN) for X-ray or drilling. The concern SN has is that they think some or all of the tubes they received from their suppliers may not have been double wall as they are supposed to be. The reported plan was to either drill the tubes (the ones the bungees go around) to check for double wall and then patch the hole in such a manner so as to minimize the stress-riser, or x-ray the tube (more likely) to see if it is double walled. If it is not, then they would probably place a reinforcing tube inside the existing tube and re-weld, then return the gear.
I’m not really understanding this report and plan, because even if their tube supplier accidentally provided single wall instead of double wall material, when SN/Atlee-Dodge did the welding, one would think that the single or double wall nature of the tubes would be obvious.
No AD for now…I guess we’ll see what happens. I did do the inspection they recommend and mine has no deformation despite about a decade of off-field use and ski landings.

 

[Larson]

Interesting.. I would have thought the manufacturing part of the STC would have specified tube specifications, with some sort of release note for the raw materials? Records?

let’s hope they work this out and make good.

 

[l.calame]

North Seaplane sold parts to Aviat or Aviat as is own building extended gear ????

 

[tbienz]

Seaplanes North has the HD gear and Extended HD Gear. Aviat later also offered standard and extended gear. I have the Seaplanes North Extended HD gear. I haven't gotten down and measured angles and such, but having flown with friends that have the Aviat extended gear, I think the tube diameter seems larger on the HD gear (but apparently some are failing anyway), the HD gear has a wider stance (good stability off-field and on skis). The Aviat extended gear has the plane sitting a bit higher (better prop clearance, slightly worse visibility especially if you are not tall), and with the tires sitting a bit further forward (better for hard braking after landing, a bit more weight on the tail with later tail rise on takeoff roll). I have seen failures of both types of gear.

 

[tbienz]

Seaplanes North has issued a “mandatory service bulletin” for removal of the gear. They are formulating a plan to replace/rework the gear. But it sounds like it will take a very long time.