SDR 2023F00043

Service difficulty report · Cylinder · Cessna 421C

Difficulty date
January 26, 2023
Submitted
February 3, 2023
Operation
General aviation
Aircraft
N421J
Make and model
Cessna 421C
Aircraft serial
421C0033
Aircraft time
9,334 hours
Engine
Cont GTSIO520L
Engine time
978 hours
Part
Cylinder
Part number
658603A6BP
Part serial
AC17DB569
Condition
Seized
Location
R/E #4 Cylinder
Part time
978 hours
Component
Engine · Cont · GTSIO520L
Component part number
GTSIO520L
Stage of operation
CR
How discovered
V
Nature of condition
R, O
Precautionary procedure
E, B, A

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

What was found

WHILE IN CRUISE FLIGHT AT 19,000 FT, PILOT NOTICED THE RIGHT ENGINE SURGING. HE SUSPECTED IT WAS A FAILED FUEL PUMP AND WHILE ATTEMPTING TO REMEDY THE SITUATION, HE THEN NOTICED MAP DROPPING AND A COMPLETE LOSS OF OIL PRESSURE. THAT IS WHEN HE DECIDED TO SHUT DOWN THE RIGHT ENGINE AND MAKE AN UNSCHEDULED, EMERGENCY LANDING IN POCATELLO, ID. THE ISSUE WITH THE ENGINE STARTED ABOUT 1 HOUR AND TEN MINUTES AFTER TAKEOFF FROM HELENA, MT. THE PLANE TOOK OFF AT 4:18PM ON 1-26-23 AND LANDED AT 5:55PM FOR A TOTAL OF 1 HOUR AND 37 MINUTES OF FLIGHT TIME. UPON INSPECTION OF THE SEIZED-UP RIGHT ENGINE, I FOUND THE #4 CYLINDER PISTON HAD COMPLETELY BLOWN OUT AND YOU COULD SEE THE CRANKSHAFT THROUGH THE SPARK PLUG HOLE. THE CYLINDER EXTERIOR LOOKED FINE OTHER THAN SOME OIL THAT HAD BLOWN AROUND INSIDE THE ENGINE COMPARTMENT. I COULD NOT DETERMINE THE SOURCE OF THE OIL LEAKS. THERE WAS STILL 9 QUARTS OF OIL READING ON THE ENGINE DIPSTICK. I REMOVED ALL THE TOP SPARK PLUGS AND COULD NOT SEE ANY DAMAGE TO ANY OF THE OTHER CYLINDERS. I REMOVED THE ALTERNATOR AND DID NOT SEE ANY DAMAGE TO THE GEARS FORWARD OF THE #5 AND #6 CYLINDERS. I DID ATTEMPT TO DRAIN SOME OIL, BUT METAL WAS BLOCKING THE DRAIN. I I HAVE CUT OPEN THE OIL FILTER AND CONFIRMED THAT IT IS FULL OF METAL AS WELL.

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