Check Oil Reservoir Mounting Bracket for Fracture XT-912 Trike

[Guest davidh10]

Last evening during my pre-flight checks, I found that the oil reservoir had a little more play than I felt was normal. Definitely not loose, but just able to be moved by a very small amount by applying some force to "wiggle it".

 

At first I thought one of the two bolts may have just needed another half turn to tighten it a little, but on more detailed investigation, discovered that the bracket had fractured. The first picture shows the bright edge of the fracture that could only be seen by applying quite a bit of force to flex the oil reservoir outwards from the bracket (you can see my fingers doing so in the photo). The second photo shows the broken bracket after disassembly.

 

[ATTACH]12109.vB[/ATTACH] [ATTACH]12110.vB[/ATTACH]

 

Closely examining the fracture, you can see that there is some bright metal, but also some light oxidation on parts of the fracture, showing that this is something that has developed over a reasonable period of time.

 

The trike has just over 800 hours of engine run time, which I think is more relevant than airframe flight hours in this circumstance.

 

 

 

 

[Guest Maj Millard]

Good stuff David and thanks for sharing this info. It can keep people out of unnecessarily dangerous situations for sure.

 

I'm not too familiar with the Airborne 912 trike, but I do know the 912 oil tank has some weight to it, and gets pretty hot during operation. If it is mounted remotely via welded brackets the chance of failure as you have highlighted is possible. I'm can only assume you have touched base with the Airborne folk on the subject?...................Maj...

 

 

[alf jessup]

Hi David,

 

Yeah i found mine cracked also at about 600hrs and took the bracket off and took it to a welding shop to get tig welded, that was 140 hrs ago and it is one thing i check every flight from now on.

 

It could have been cracked a lot earlier than that as i noticed it had some play in it but origanally thought it was just the band flexing as I couldnt see anything amiss when looking at it.

 

It was only one day when i thought i would just see if i could tighten it and i couldnt i delved further into it and took the bracket off which is not easy to access and saw it had broken right through.

 

I never even thought of putting a post in as i thought it was a one off thing that only affected mine.

 

Well done on the post i commend you for putting it in.

 

Note to all owners it should be frim and not have any movement in it, if it does look into it.

 

Cheers

 

Alf

 

 

[Guest davidh10]

...I'm can only assume you have touched base with the Airborne folk on the subject?...................Maj...

Not yet, as it was discovered on Friday evening. I'm flying again today on a combination MIG / TIG welded repair that has added a fillet for reinforcement, but on Monday will be ordering a replacement from Airborne, so they will be informed then.

 

The bracket is a one piece folded steel (formed) bracket, so I can only assume that in the original process it has work hardened and started the crystallisation process. I'll only be using the repaired bracket until the replacement arrives, as without metalurgical examination (which is usually destructive), who knows whether the crystalisation has extended beyond the immediate bend... hence the fillet in the repair. The other bend does not seem to have been affected, based on a simple flex test and I'm satisfied that the repaired bracket is not in danger of failing in the short time it will be in use.

 

 

[Guest davidh10]

Airborne has acknowledged that they have seen a few occurrences of this bracket failure.

 

 

[Tracktop]

Hi David / Alf

 

Is the tank still held fairly firmly ( your detected failed condition ) when the bracket is fully fractured or only when partially cracked?

 

Just wondering if when cracked through fully on one side it was close to critical engine failure ( lose of oil tank / oil ) or a much nicer case of early detection?

 

Thanks for the heads up - good place to keep an eye on

 

Ray

 

 

[alf jessup]

Hi David / AlfIs the tank still held fairly firmly ( your detected failed condition ) when the bracket is fully fractured or only when partially cracked?

Just wondering if when cracked through fully on one side it was close to critical engine failure ( lose of oil tank / oil ) or a much nicer case of early detection?

 

Thanks for the heads up - good place to keep an eye on

 

Ray

Ray,

 

The tank was still held quite firmly in place even though one side of the mounting bracket was broken clean though and i dont think there was much chance of it causing an engine failure as even if both brackets let go you would still have the hoses retaining the sump.

 

Just a early pick up i would say.

 

Cheers

 

Alf

 

 

[Guest davidh10]

Hi David / AlfIs the tank still held fairly firmly ( your detected failed condition ) when the bracket is fully fractured or only when partially cracked?

Just wondering if when cracked through fully on one side it was close to critical engine failure ( lose of oil tank / oil ) or a much nicer case of early detection?

 

Thanks for the heads up - good place to keep an eye on

 

Ray

I concur with Alf. The fracture was only visible after applying significant force to pull the oil tank away from the frame, even then only by a couple of millimetres (see the photo in my original post). The indication was that the oil tank was able to be wobbled a little and rotated a couple of degrees in the vertical plane instead of being rigidly attached to the frame. I would not characterise it as "loose".

 

There was no risk of engine failure or the tank coming adrift while one side of the mounting bracket was intact.

 

If both sides of the mounting bracket were to fracture, then the tank would flop around, attached only by the oil hoses. In that scenario, the tank would drop to a lower level and there may be a risk of kinking an oil hose or having an oil hose contact the hot exhaust manifold. The force of the airstream could also result in a changed attitude of the tank. In other words it may not be fully vertical. I cannot comment on the resultant risk of engine failure that may create.

 

 

[Kev]

Please file a Defect Report.

 

This is an important and necessary step in the dissemination of the information and ultimately the rectification of any recurring defect.

 

If you are HGFA registered, the Defect Report may be filled out on-line on the HGFA website.

 

If you are RAAus registered, the Defect Report is available from your Technical Manual Section 43-3.

 

Safe Flying

 

Kev