Swaged control cable fittings – aging aircraft issue?

[Charlie Tripp]

I have a very good friend who flies a 1975 Beech V35B. He had planned to fly from Jackson TN to West Palm Beach FL to visit his dad on Monday April 27th. On Sunday April 26th he went to the airport to check his plane before the planned flight. Since we only have community hangers at the airport he found his plane was on the ramp since a plane behind his had to be pulled out for a flight. That Sunday the wind was really gusting all day. While walking up to his plane on the ramp he noticed both ailerons drooping down. Control wheel input did not produce any movement of the ailerons!

On Monday April 27th Paul New of Tennessee Aircraft Services was shocked at what he found. The control cable swaged terminal at the turnbuckle used to adjust cable tension located at the aileron bell crank in the wing had separated in half! There was no damage to aileron hinge points or stops. None of his mechanics had ever seen this. The cable was in excellent shape. A call was made to Beechcraft and they replied they had never heard of this before. There was “brown stuff” on the terminal that appeared to be chemical remains. Inside the cavity of the terminal was some “crusty stuff”.

Paul said from now on he will be checking all cable terminals during an annual by applying side pressure to the terminal with his thumb and two fingers. I definitely will be checking the cable terminals on the Comanche at the upcoming annual.

Pictures Attached

[Hansmeister]

This appears to be a very solid case of corrosion. The question is where did the corrosive medium come from. Check all cables, check all places for liquids Iinternal and external leaks).

[Paul New]

This cable end was located in a very accessible area of the airplane and was visually inspected during an annual inspection in October of 2008. We always look at all turn buckles and ends of cables as a mater or routine. As far as we know, there were no indications of a problem at that time.

If there was some indication it may have been passed over because a failure of this type has never been seen before. Unfortunately, mechanics tend to look for expected failures. We have modified our inspection procedures to try to ensure this type of problem gets caught early.

[Zach Grant L1011jock]

Some case of internal galvanic corrosion perhapse. Were these stainless cables?
-Zach