NTSB Identification: SEA91FA076.
The docket is stored on NTSB microfiche number 43917.
Accident occurred Thursday, March 28, 1991 in CHEHALIS, WA
Probable Cause Approval Date: 07/13/1993
Aircraft: PIPER PA-24-250, registration: N6044P
Injuries: 1 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.

DURING A CROSS COUNTRY FLT, THE ENG LOST PWR. DURING THE EMERGENCY DESCENT, THE AIRPLANE COLLIDED WITH A BUILDING. THE POST CRASH ENG INSPECTION REVEALED THAT THE CRANKSHAFT GEAR WAS NOT SEATED PROPERLY DURING THE MAJOR OVERHAUL, WHICH RESULTED IN THE FATIGUE FAILURE OF THE CRANKSHAFT DOWEL. FURTHER RESEARCH REVEALED THAT DURING THE ENG OVERHAUL, A SERVICE BULLETIN WAS NOT COMPLIED WITH TO INSTALL A CRANKSHAFT GEAR THAT WAS MANUFACTURED WITH THREE, THREE QUARTOR INCH RADIUS SCALLOPS. THESE SCALLOPS ALLOW FOR INSPECTION OF THE GEAR AND CRANKSHAFT ASSEMBLY.

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

A LOSS OF ENGINE POWER DUE TO AN IMPROPER OVERHAUL.

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