Service difficulty report · Cover · Bell 407

Difficulty date
May 2, 2002
Submitted
July 2, 2002
Operation
Air carrier
Aircraft
N403AL
Make and model
Bell 407
Aircraft serial
53478
Engine
Allsn 250C47B
Part
Cover
Part number
23065470
Part serial
HL15428
Condition
Stripped
Location
Gearbox
Part time
752 hours
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

(GEARBOX COVER) UPON DISASSEMBLY OF GEARBOX, FOUND 1 EACH STRIPPED STUD AND 2 EACH LOOSE STUDS AT 2.5 BEARING CAGE MATING SURFACE, ALSO FOUND 2 EACH STUDS AT TM SUPPORT JOURNAL LOOSE. NOTE: AT LOCATION OF STRIPPED STUD ON T.5 BEARING CAGE SURFACE, FOUND NO THREADS IN STUD BORE. NOTE: THISCONDITION COULD POSSIBLY CAUSE CATASTROPHIC GEAR FAILURE. URGENT: INSTALL HELICOILS IN STUD BORES AT FACTORY TO ALLOW FOR HIGH TORQUE OF ENGINE IN THIS AREA.

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