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ACRO E-mail Archive Thread: [IAC] Crankshaft AD on AEIO-360


Thread: [IAC] Crankshaft AD on AEIO-360

Message: Re: [IAC] Crankshaft AD on AEIO-360

Follow-Up To: ACRO Email list (for List Members only)

From: "Drew Lundgren" <acrodrew at>

Date: Fri, 19 Dec 1997 15:09:50 UTC


My experience with my old Pitts S-1S was that a Magnaflux job took about 2
to 2 hours.  This included all the time from when we began removal of the
spinner until the spinner was back on the airplane.  The Magnaflux process
wasn't a problem with my magnetic compass because we'd take it out when we
did the test.  Then, after the test and degaussing of the crankshaft, we'd
degauss the frame before reinstalling the compass.  To degauss the frame we
put the energized gaussing coil in the cockpit area and slowly removed it
and walked away from the airplane all the while keeping the coil energized.
 This may or may not be applicable to other airplanes.  I just know that a
gaussmeter showed no magnetism on the airplane anywhere; including the
crankshaft which had been similarly degaussed before we did the same thing
to the airframe.  

Yes, we found a crack between the lightening holes on the IO-360's crank
and it cost quite a bit to repair.

Drew Lundgren, IAC 25, Houston

> From: Cummings, Steve - TP1SMC <scummings at>
> To: iac at
> Subject: RE: [IAC] Crankshaft AD on AEIO-360
> Date: Friday, December 19, 1997 10:50 AM
> Olga,
> If a crack develops that is at least partly on the surface, the dye
> penetrant method will work fine. This method is very simple and
> inexpensive (you can get the dye check kit from Aircraft Spruce and
> other places and it's good for many inspections). If the crack is
> developing within the flange and has not reached the surface, only
> magnaflux would detect it. I do not trust the visual inspection method.
> Here's why.  I had the unfortunate experience of finding a crack in my
> prop flange during an annual inspection. The cracks normally form at and
> between the lightening holes. Mine was discovered using the dye
> penetrant method. To my surprise, after cleaning up the flange, the
> crack "disappeared." Knowing exactly where it was and using a 10x
> magnifying glass, it was almost impossible to see. The angle and
> lighting had to be exactly right to see it. And even then, you could
> easily mistake it for a scratch. You'd better know exactly what you're
> looking for. The crack has to be pretty far along before you will easily
> detect it visually using a magnifying glass. But you don't want it to
> get that far along. My understanding is that these type of failures tend
> to occur in an exponential manner. That is, they start out slowly but
> progresses exponentially with time such that most of the failure comes
> rapidly right at the end of the part's useful life. In other words, by
> the time you are able to detect it visually, you are probably very far
> along on the failure curve.
> The dye check method should not take longer than about 2 hours total
> time to perform. This includes removal and replacement of the prop and
> nose bowl, cleaning up the flange prior to applying the dye, waiting for
> the dye to penetrate and applying and waiting for the developer. If you
> are having this done by an A&P and are told it will take longer than two
> hours, you would do well to shop around. If you do it yourself, it will
> take longer the first time because of the learning curve. Once you get
> the hang of it, you will be able to do it fairly quickly. Your best bet
> is find someone in your local IAC chapter who has experience and ask
> them to help you through it the first time. If you don't belong to a
> local chapter, now would be a good time to join.
> As for magnaflux, I believe it is normally reserved for components that
> have been removed from the  engine and which must be "re-certified." I
> know they have portable units, but I have no idea what the time
> requirement is to perform the test. Be advised that if you have the
> magnaflux method done while the engine is in your airplane, you might
> thoroughly screw up your magnetic compass as the airframe could become
> permanently magnetized.
> Based on my experience, dye penetrant is your best bet.
> Hope this helps.
> Steve Cummings
> Corona, CA
> scummings at
>  ----------
> From: Olga Mitchell
> To: iac at
> Subject: [IAC] Crankshaft AD on AEIO-360
> Date: Thursday, December 18, 1997 6:58PM
> In AEIO-360 engines that do not have a solid crankshaft, AD 84-13-5
> specifies visual inspection of the crankshaft flange every 25 hours time
> in
> service or a Magnaflux inspection every 100 hours time in service.  This
> inspection requires removing the prop.  I have been told that it takes
> about
> 6 hrs to do this inspection.
> I'd appreciate information on experience with complying with this
> AD--relative costs of the two methods, availablity of the portable
> Magnaflux
> method, and any other relevant information.
> Thanks.
> Olga Mitchell
> IAC #14229


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