Service difficulty report · Slip Joint · Schler ASK21

Difficulty date
March 1, 2009
Submitted
March 19, 2009
Operation
General aviation
Aircraft
N966TS
Make and model
Schler ASK21
Aircraft serial
21820
Part
Slip Joint
Condition
Corroded
Location
Control Stick
Stage of operation
IN
How discovered
V
Nature of condition
O
Precautionary procedure
K

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

CORROSION WAS FOUND AT THE JUNCTION OF THE UPPER AND LOWER BODY OF THE FRONT SEAT CONTROL STICK ASSY. THE UPPER STICK HALF SLIDES INTO THE LOWER STICK HALF AND IS THEN HELD TOGETHER WITH A SINGLE THROUGH BOLT. THE CORROSION WAS DETECTED PROTRUDING FROM THE TOP OF THE JOINT WHERE THE UPPER PIECE SLIDES INTO THE LOWER PIECE OF THE ASSY. THE EXTENT OF THE CORROSION COULD NOT BE DETERMINED WITHOUT REMOVEING AND DISASSEMBLING THE STICK. CORROSION WAS SEVERE ENOUGH THAT SEPARATION OF THE (2) STICK PARTS WAS ACHIEVED ONLY AFTER APPLICATION OF HIGH HEAT FROM A TORCH. THE PROBABLE CAUSE IS PERSPIRATION FROM THE PILOT`S HAND DRIPPING DOWN THE STICK TO WHERE THE PARTS ARE MATED. CORROSION EASILY DEVELOPS WHEN THE MOISTURE CONTACTS THE BARE METAL IN THE JOINT. WHAT IS DISTRUBING IS THAT THE ACFT HAS ONLY BEEN IN SERVICE FOR LESS THAN 2 YEARS SINCE NEW. MFG SHOULD HAVE PROVIDED BETTER CORROSION PREVENTION OR DESIGN. SHOULD CORROSION BE ALLOWED TO CONTINUE, THAT THE CONTROL STICK WILL ULTIMATELY FAIL. INSP OF (2) OTHER ACFT OF THE SAME MAKE, MODEL AND IN-SERVICE TIME REVEALED SIMILAR CONDITIONS. (K)