Service difficulty report · Exhaust Valve · Cessna 402C

Difficulty date
November 17, 2010
Submitted
November 19, 2010
Operation
Air carrier
Aircraft
N6879R
Make and model
Cessna 402C
Aircraft serial
402C0611
Aircraft time
26,708 hours
Engine
Cont TSIO520VB
Engine time
1,237 hours
Part
Exhaust Valve
Part number
637781
Condition
Failed
Location
Zone 400
Part time
1,237 hours
Stage of operation
CL
How discovered
O
Nature of condition
R
Precautionary procedure
E, A

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

What was found

CREW REPORTED, DURING INITIAL CLIMB OUT, EXPERIENCED PARTIAL POWER LOSS ON RT ENG, CONSISTENT WITH LOSS OF TURBOCHARGER. CONTINUED CLIMB OUT AT FULL POWER TO CRUISE SETTING AT 7000 FT WHILE DECLARING AN EMERGENCY AND REQUESTING DIVERSION. EXPERIENCED OIL LEAK FROM RT COWLING ENROUTE, LOST ALL OIL PRESSURE ON RT ENGINE, AND PERFORMED PRECAUTIONARY SHUTDOWN. CONTINUED ENROUTE AND LANDED WITHOUT INCIDENT. MX INSPECTED RT ENGINE, AND FOUND TURBOCHARGER FAILED ALONG WITH OIL PRESSURE FEED LINE FRACTURED. R & R TURBOCHARGER, OIL FEED LINE, AND AS A PRECAUTIONARY MEASURE, R & R RT ENGINE. FURTHER INSP REVEALED NR4 CYLINDER EXHAUST VALVE HAD FAILED. DEBRIS FROM THE FAILED VALVE HAD TRAVELED THROUGH THE EXHAUST SYS, DAMAGING THE TURBOCHARGER. ABRUPT STOPPAGE OF THE TURBOCHARGER CAUSED THE COMPRESSOR PARTING HALF CLAMP TO FAIL, FRACTURING THE TURBOCHARGER OIL PRESSURE FEED LINE. AFTER THE ENGINE AND TURBOCHARGER WERE CHANGED, THE AIRCRAFT WAS RELEASED BACK TO SERVICE.

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