Service difficulty report · Cotter Pin · Dhav DHC2MKI

Difficulty date
August 12, 2008
Submitted
November 3, 2008
Operation
General aviation
Make and model
Dhav DHC2MKI
Aircraft time
23,702 hours
Engine
Pwa R985AN14B
Propeller
Hartzl HCB3R304
Part
Cotter Pin
Part number
10185
Condition
Missing
Location
Governor
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

(CAN) DURING ENG INSP, TWO COTTER PIN TAILS WERE FOUND IN ENG ACCY SUMP. INVESTIGATION INTO SOURCE OF PIN TAILS REVEALED THAT COTTER PIN (P/N 10185) SECURING NUT (P/N 23212) FOR GOVERNOR DRIVE GEAR SHAFT (P/N 2715) IN ACCY SECTION WAS MISSING. THERE WAS EVIDENCE OF PIN HAVING GONE THROUGH THE GEARS AND REDUCED TO METAL PARTICLES. OVERHAUL SHOP WAS CONTACTED AND REVEALED THAT THEY HAD A NEW EMPLOYEE ASSEMBLING THIS SECTION OF ENG, AND WAS USING STANDARD COTTER PIN INSTALLATION PROCEDURE. IN THIS LOCATION, IF THE PIN IS INSTALLED WITH TAIL FOLDED BACK OVER END OF SHAFT, IT WILL CONTACT INSIDE OF GOVERNOR BASE AND BREAK OFF. ONCE THIS HAPPENS, THE SHORT END OF COTTER PIN CAN ROTATE AND ALSO CONTACT THE INSIDE OF GOVERNOR BASE AND BE BROKEN OFF. PROPER COTTER PIN INSTALLATION PROCEDURE TO PRECLUDE INTERFERENCE IS TO BEND LONG END OF THE PIN DOWN INTO THE HOLLOW CENTER OF THE SHAFT. THIS WILL PREVENT ANY CONTACT WITH HOUSING OF GOVERNOR. OVERHAUL SHOP HAS TRAINED THEIR PERSONNEL IN THE PROPER PINNING PROCEDURE FOR THIS LOCATION. THIS IS AN EASY CONDITION TO BE AWARE OF AND CORRECT DURING ENG BUILDUP. ENG TSOH 195.7 HOURS.