FAA considers Superior Air Parts crankshaft assembly AD

[Thermos]

Originally Posted by rv6ejguy

If all material, heat treatment and hardness is within specs and the engines were operated within specs with approved props so harmonics are not an issue, these cranks should not have broken. Multiple reasons for failure may open more cans of worms.

Those are good words, Ross. These are PMA'd crankshafts so Superior/ECi had to show that they meet the same design and production standards as the original Lycoming part. To the best of my knowledge, Lycoming's crankshafts haven't had problems and it's reasonable to assume that they've been exposed to the same usage spectrum as Superior/ECi's products.

Dave

[walkman]

Originally Posted by rv6ejguy

If ... the engines were operated within specs with approved props so harmonics are not an issue, these cranks should not have broken..

This is part of the problem. From memory at least one of the reports indicated a possible prior prop strike.

[JPGrobler]

Anyone with latest news on this matter? Burning to get back in the air!

[walkman]

Originally Posted by JPGrobler

Anyone with latest news on this matter? Burning to get back in the air!

There's no AD at the moment, and you're flying an experimental anyway. There's nothing keeping you on the ground except your own suspicions.

If I wasn't down for maintenance I'd do at least local flying. Maybe not long over water or IFR legs though.

Mar 16 is the date on the NPRM

[Onewinglo]

AOPA made a formal comment on the proposed AD.
https://www.regulations.gov/contentS...ontentType=pdf

[JPGrobler]

Originally Posted by Onewinglo

AOPA made a formal comment on the proposed AD.
https://www.regulations.gov/contentS...ontentType=pdf

Thanks for the link.

But delay the entire process by another 2 months? I?m sure most operators would rather just like to get this resolved as quickly as possible?

If I knew the risk is minimal, I would still be flying, but getting up in the air now feels like playing russian roulette - knowing you have a potential issue, choose to ignore it and then just ?hope for the best?... not the way I think a good aviator should take to the skies.

Aviation, especially general aviation, is a game of risks and when we take to the skies we take calculated risks, be it with weather, fuel reserves, runway lengths, takeoff weight or mechanical dependability. Maintaining the aircraft I fly to the highest standard has always been my goal to know I can trust the machine I carry myself and loved ones in. Knowing there is a potential flaw (probably fatal) in the system and going for a flight is borderline reckless in my opinion.

We spent tens of thousands of dollars of our hard earned money buying a ?Superior? engine that now turned out to be ?inferior?. I think it?s time for Superior to step up to the plate and give a decent response as to how we are going to get this resolved ASAP.

The FAA won?t send a serious note like this out ?for the fun of it?. I?m sure they will have valid reasons for their evaluation of the flaw in the crankshafts. AOPA extending the comment time won?t make the crankshafts fix themselves over said period. They have to be replaced at one stage or another anyway.

Maybe my view on this is flawed, but it is how I see it and I truly hope it can be resolved for once and for all.

JP

[Onewinglo]

SAP posted three documents to the proposed AD:
A Response,
A Request of extension and
A SAE document about Gas Nitriding of Low-Alloy Steel Parts.

https://www.regulations.gov/document...2018-1077-0005

[Cannon]

Just read Superior?s response.

Cliff?s notes as I read it:
An independent lab looked at each crank.
All three cranks were well within the ?white layer? spec.
All three cranks showed signs of abuse.
All three cranks were in a flight school environment.

[theduff]

I found it interesting in the second metallurgical report they found:
?The tensile properties of the Crankshaft material were outside the range of the specified limits?
They went on to say this wasn?t the cause of the failure but if your crankshaft as manufactured doesn?t meet specifications for tensile strength isn?t that a problem ?

[skylor]

Originally Posted by theduff

I found it interesting in the second metallurgical report they found:
?The tensile properties of the Crankshaft material were outside the range of the specified limits?
They went on to say this wasn?t the cause of the failure but if your crankshaft as manufactured doesn?t meet specifications for tensile strength isn?t that a problem ?

According to the Superior response, 2 of the 3 crankshafts failed to meet requirements.