SDR 98ZZZX1986

Service difficulty report · Valve Spring · Cessna 421C

Difficulty date
March 4, 1998
Submitted
March 26, 2000
Operation
General aviation
Aircraft
N748CA
Make and model
Cessna 421C
Aircraft serial
421C0905
Engine
Cont GTSIO520N
Part
Valve Spring
Part number
631521
Condition
Failed
Location
Nr 1 Cylinder
Part time
859 hours
Component
653452D
Stage of operation
CL
How discovered
9
Nature of condition
E
Precautionary procedure
A

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

What was found

PILOT REPORTED VIBRATION ON RT SIDE OF AIRCRAFT DURING TAKEOFF ROLL AND CLIMB OUT. COULD NOT CORRECT WITH ENGINE CONTROLS (RPM, M.A.P., FUEL OR MAGS). RETURNED TO AIRPORT MAINT FACILITY AND REPORTED OUT OF BALANCE PROP. UPON MAINT GROUND RUN, ENG RAN ROUGH, VIBRATION AT IDLE RPM AND BACKFIRING OUT THE EXHAUST. DIFFERENTIAL COMPRESSION CHECK REVEALED NR 1 CYL AT ZERO COMPRESSION. UPON FURTHER INSP, NOTED 3 PIECES WITH SUBSEQUENT DAMAGE TO THE GUIDE AND VALVE. DAMAGE TO THE GUIDE WAS SO SEVERE, THE EXHAUST VALVE WAS STUCK IN THE OPEN POSITION CAUSING THE DEAD CYLINDER.

More about the Cessna 421C