NTSB Identification: NYC91LA092.
The docket is stored on NTSB microfiche number 43095.
Accident occurred Saturday, March 23, 1991 in WESTBROOK, ME
Probable Cause Approval Date: 05/05/1993
Aircraft: PIPER PA-23-160, registration: N4155P
Injuries: 4 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

ON AN IFR FLIGHT IN IMC CONDITIONS THE RIGHT ENGINE STARTED TO SHUDDER AND PRODUCE BLACK SMOKE, AND THEN THE PROPELLER WENT INTO FEATHER WITHOUT ACTUATION OF THE PROPELLER CONTROL. THE PILOT WAS UNABLE TO MAINTAIN ALTITUDE AND THE PILOT MADE A FORCED LANDING IN AN OPEN FIELD. THE RIGHT ENGINE OIL WAS DILUTED BY GASOLINE, DUE TO A LEAK IN THE ACCELERATOR PUMP OF THE CARBURETOR WHICH CAUSED THE ENGINE TO RUN RICH. INTERVIEWS DISCLOSED THE PILOT HAD 'DENIAL' ON THE ENGINE PROBLEM, DID NOT SECURE THE ENGINE, AND DID NOT DECLARE AN EMERGENCY WITH ARC. BOTH ENGINES WERE HIGH TIME WITH HIGH TIME SINCE OVERHAUL. HARTZELL PROPELLERS PERSONNEL VERIFIED DILUTED OIL COULD CAUSE A PROPELLER TO GO INTO UNCOMMANDED FEATHER.

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

IMPROPER EMERGENCY PROCEDURES BY THE PILOT. FACTORS RELATED TO THE ACCIDENT WERE: THE PILOT'S LACK OF EXPERIENCE AND FLIGHT TIME IN TYPE OF AIRPLANE, THE PILOTS DECISION TO TAKE AN AIRPLANE WITH A KNOWN MECHANICAL DEFECT, A LEAKY ACCELERATOR PUMP SEAL ON THE CARBURETOR, AND INSTRUMENT METEOROLOGICAL CONDITIONS.

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