VAR crank in experimentals question-

[fairchild]

If I could find a 540 of some kind that contained the "Bad" (per AD) non-VAR crank---- would I be allowed to use it in an uncertified homebuilt ?
I have read that the new VAR cranks have a higher failure rate than the old one that it replaces. Many seem to believe that this AD was pushed through by Lycoming as a liability CYA and
they really didn't care if it REALLY solved the problem or not----

Any thoughts ? Experiences ?

Tim

[Bdflies]

I was all prepared to say that AD's don’t apply to EAB aircraft, unless the manufacturer (you) deem it so. Uncharacteristic for me, I decided to verify that info, before posting. I think this document holds the answer you seek;

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC%2039-7D.pdf

Section 9 (a) (1) addresses your question. As I read it, the answer to your question is "it depends". It depends on the wording of the AD in question. If you post the exact AD that you’re questioning, I’m sure someone would volunteer a more definitive response.

Bill

[whee]

I learned recently that I don’t know as much about this topic as I thought I did so I hesitate to respond.

Check any AD to see if it includes special airworthiness certificate aircraft. Check with the DAR that will be performing your airworthiness inspection. Check with the company that will be assembling your engine. Their responses will determine your options.

[BravoGolf]

Plus 1 on what Whee said. I purchased a midtime engine from a flying aircraft. I did the AD research to see if they had been complied with, The DAR asked about the ADs even as we discussed experimental requirements. Glad I had the list. So it just depends on who you are working with, DAR, engine shop etc.

[zkelley2]

I'm of the opinion, as well as a local DAR and a couple A&P's that do conditionals, that while AD's don't have to be complied with per se, if it effects the safety of flight, you'd need to come up with some way to address the safety of flight condition outlined.

For example, if you had decided to install Cessna Style seat rails that have the AD about sliding backwards on takeoff, you don't have to put the stops in as outlined in the AD, but you do need to do something that accomplishes the same thing.

An engine shop would be insane to put a crank back into an engine that has an AD on it that require it be tossed.

[fairchild]

From what I have researched about the "reality" of the crankshaft AD--- and talking to several mechanics---- that even though there were some cranks that had broken which ---
and it appears that lycoming requested that the FAA generate an AD to remove ALL cranks (as a political CYA) and replace them with new VAR cranks knowing the VAR was no better than the old ones. From what I have read --- the new ones have a higher breakage rate than the old ones. So it appears that the reality of the situation is that you could not say that safety is enhanced
by installing a new crank. Of coarse a new crank would have zero hours--- but that's a different problem---

The fly in the pudding might be the forced compliance with the AD probably has NOTHING to do with the validity of the thing..... because the beauracrats seem to care more about
paperwork than if the thing is increasing safety or decreasing it...…….

I know a retired FAA guy I can ask this of the next time I see him.
In the mean time I will read that link you supplied !
Thanks
Tim

OK-- that link kind of helped ----

b. Non-TC’d Aircraft and Products Installed Thereon. Non-TC’d aircraft (e.g., amateur-built aircraft, experimental exhibition) are aircraft for which the FAA has not issued a TC under part 21. The AD applicability statement will identify if the AD applies to non-TC’d aircraft or engines, propellers, and appliances installed thereon. The following are examples of applicability statements for ADs related to non-TC’d aircraft:

So it looks like it depends if the AD says "any aircraft" ------ or "any certified aircraft". So I will have to find the exact AD that applies to whatever engine
in question-----

T