08-14-2013 Ask Mike! Question
Looking at A36's and the Spar AD

Mike,

You have great info on the AVSTAR website, and you have some loyal customers on the ABS website.  I am in the market for an A36 and have gotten various opinions on whether I should avoid aircraft that have spar cracks, even if they have been repaired.  The kit installation looks very difficult.  Does it help to remove the wings to reach the lower huck bolts?  It that a major cost increase?  If I find an A36 with no cracks, have you seen the higher-time airplanes get cracks later or does it depend at all on time-in-service? 

Thanks!
Dennis

Hi Dennis;

The repair of the carry-through spar is only as good as the person(s) that did it, we have had to "re-install" a few of them that were improper.  I have said it before, and will again:  A good pre-purchase inspection is money in the bank.

The installation can present a few challenges.  We have never had to pull a wing to do an installation; there is no time benefit considering the time to remove and replace a wing.  That said, a number of the fasteners would be easier to get to with the wing off, if it was off for other work.

I am also still of the opinion that the cracks are caused by one or a combination of two factors:  1)  Improper preparation of parts before assembly at the factory, meaning holes not properly de-burred and lack of radius on the end of the J-stringer before it is buried into the radius of the web (imagine the square peg in a round hole), and 2) Abuse in the form of hard landings and/or extreme G-forces.

I have heard of A36's used in flight training that have 15,000 plus flight hours and no cracks.

Gear Green,
Mike