Flight Controls free, correct (AD for Piper yokes)

[twdeckard]

http://rgl.faa.gov/Regulatory_and_G...4F084B840160ADFA8625765F00507D4B?OpenDocument

We have received two reports of control wheel shafts that have been incorrectly assembled at Piper. The first incident concerned the loss of the control wheel on a Piper Model PA-34-220T airplane, where the right-hand control wheel shaft and universal joint separated due to a misdrilled hole for the threaded taper pin. The second report was of a ground inspection on a Piper PA-34-220T airplane that revealed a similar situation between the control wheel shaft and the universal joint in the left-hand side. Investigation following these reports revealed that the control wheel shafts had been incorrectly assembled at Piper and holes were misdrilled even though they may visually appear acceptable. The hole in the shaft may be too close to the end of the shaft, causing a significant reduction in joint strength. Since discovery of this problem, Piper has added a step to the manufacturing process and also introduced a fixture to ensure proper assembly of the control wheel shaft/universal joint.

 

[Steve Foley]

That's interesting. I wound up replacing one of the universal joints in my PA28-140. I borrowed a reamer tapered at the right angle for the taper pin. When I disassembled the old one, I found a nut and bolt holding it together, not a taper pin at all.