NTSB Identification: ANC94FA106.
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Nonscheduled 14 CFR
Accident occurred Sunday, August 14, 1994 in KENAI, AK
Probable Cause Approval Date: 09/24/1995
Aircraft: PIPER PA-32-260, registration: N4839S
Injuries: 3 Fatal,1 Serious.

NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.

THE AIRPLANE WAS ON A PART 135 ON-DEMAND AIR TAXI FLIGHT, WHEN PHYSICAL SEPARATION OF THE NO. 3 CYLINDER AND PISTON OCCURRED AND AN IN-FLIGHT FIRE ENSUED. SUBSEQUENTLY, THE AIRPLANE CRASH LANDED ON TERRAIN NEAR THE SHORELINE OF A BODY OF WATER. ONE OF THE FOUR OCCUPANTS SURVIVED THE CRASH, BUT THE SURVIVING PASSENGER COULD NOT RECALL EVENTS THAT LED TO THE ACCIDENT. MAINTENANCE RECORDS INDICATED THAT THE #3 AND #4 CYLINDER ASSEMBLIES WERE INSTALLED ABOUT 220 FLIGHT HOURS BEFORE THE ACCIDENT. THIS MAINTENANCE WAS PERFORMED WITHOUT REMOVING THE ENGINE FROM THE AIRPLANE. NO PROBLEM WITH THE AIRFRAME OR ENGINE WAS RECORDED SUBSEQUENT TO THE CYLINDER CHANGE. INSPECTION OF THE ENGINE REVEALED FATIGUE CRACKS IN THE CASE UNDER THE NO. 3 CYLINDER. MAGNIFIED INSPECTION OF THE CASE REVEALED WEAR AND DEFORMATION DAMAGE, WHERE THE HOLDING FLANGE AND INNER SKIRT OF THE CYLINDER WOULD NORMALLY BE POSITIONED, WHICH WAS CONSISTENT WITH THE CYLINDER MOVING IN RELATION TO THE CASE. ALSO, MECHANICAL DAMAGE WAS EVIDENT ON THE THREADS OF THE STUDS AND BOTH THROUGH-BOLTS.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

INADEQUATE ENGINE MAINTENANCE AND/OR INSPECTION, AND FATIGUE CRACKING OF THE ENGINE CASE, WHICH RESULTED IN EVENTUAL DAMAGE TO THE #3 CYLINDER STUDS/ENGINE THROUGH-BOLTS, SUBSEQUENT SEPARATION OF THE #3 CYLINDER AND PISTON, AND AN IN-FLIGHT FIRE.

Full narrative available

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