Service difficulty report · Control Unit · Piper PA28R201

Difficulty date
January 4, 2010
Submitted
January 15, 2010
Operation
General aviation
Aircraft
N4160F
Make and model
Piper PA28R201
Aircraft serial
2844028
Engine
Lyc IO360C1C6
Propeller
Mcauly B2D34C213
Part
Control Unit
Part number
ATF27A
Part serial
09402341
Condition
Worn
Location
Prop Governor
Stage of operation
IN
How discovered
9
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

DURING ANNUAL INSP OF ENG, FOUND PROP GOVERNOR CONTROL UNIT CONTROL ARM HIGH RPM ADJUSTABLE STOP SCREW AND STOP PIN EXCESSIVELY WORN. CONTROL ARM STOP PIN HAS A GROOVE IN WHICH CONTROL ARM RETURN SPRING IS HOOKED IN. THE WEAR BETWEEN THE ADJUSTABLE HIGH RPM STOP SCREW AND CONTROL ARM PIN IS DIRECTED ON RETURN SPRING GROOVE. OVER TIME HIGH RPM STOP SCREW AND/OR STOP PIN WILL WEAR ENOUGH TO INCREASE ENGINE SPEED WHICH WILL EVENTUALLY CAUSE AN OVERSPEED CONDITION OR COMPROMISE INTEGRITY OF CONTROL ARM RETURN SPRING ATTACHMENT. IT IS RECOMMENDED TO DESIGN STOP PIN WITHOUT RETURN SPRING GROOVE TO COME IN CONTACT WITH ADJUSTABLE HIGH RPM STOP SCREW OR CHANGE STOP SCREW AND PIN CONTACT SURFACES TO A MORE WEAR RESISTANT MATERIAL.

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