Service difficulty report · Button · Swrngn SA227AC

Difficulty date
November 26, 2007
Submitted
January 21, 2008
Operation
General aviation
Make and model
Swrngn SA227AC
Engine
Garrtt TPE33111U
Propeller
Mcauly 4HFR34C652
Part
Button
Condition
Short
Location
Mlg
Component
Mlg · Frchld
Component part number
54530013
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) UPON DISASSEMBLY OF A MLG FOR OVERHAUL AND SERVICING IT WAS NOTICED THE CYLINDER PISTON TEFLON BUTTONS WERE UNDER FLUSH WITH THE PISTON. THE TEFLON BUTTONS AND PINS ALLOW THE PISTON TO SLIDE INSIDE THE CYLINDER WITHOUT SCORING AND WITHOUT ALLOWING FLUID BLOWBY. UPON INSPECTION OF THE PISTON IT WAS NOTICED THE HOLES WERE TOO DEEP FOR THE TEFLON BUTTONS AND PINS AND ALLOWED FOR SCORING OF THE CYLINDER WALLS. WHEN COMPARED TO A KNOWN CERTIFIED PART, IT DID NOT MEET THE SAME MEASUREMENTS. ACTUAL ENGINEERING DRAWINGS WITH SPECIFIC MEASURMENTS WERE NOT AVAILABLE TO CONFIRM PISTON MEASURMENTS. LIKELY THIS PART IS SUBSTANDARD BUT THE POSSIBILITY OF BEING AN UNAPPROVED PART EXISTS. TOTAL TIME ON THE PISTON IS UNKNOWN AND IAW AIRCRAFT MFG IS TO BE MAINTAINED ON CONDITION.