NTSB Identification: CHI94DEM01.
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Accident occurred Thursday, June 02, 1994 in MUSKEGON, MI
Probable Cause Approval Date: 02/24/1995
Aircraft: GRUMMAN G-164A, registration: N8939H
Injuries: 1 Uninjured.

THE AERIAL APPLICATION FLIGHT HAD COMPLETED ONE PASS OVER A FIELD AND WAS MAKING A CLIMBING TURN IN PREPARATION FOR A SECOND SWATH RUN. DURING THE CLIMBING TURN THE PILOT REPORTED THE ENGINE QUIT WITH A LOUD BANG WHILE OVER A LAKE NEXT TO THE AREA BEING SPRAYED. THE PILOT SAID HE TURNED TOWARD SHORE AND RAPIDLY DECELERATED. HE SAID HE PITCHED THE AIRPLANE DOWN TO KEEP IT FROM STALLING. THE AIRPLANE DESCENDED IN A STEEP NOSE DOWN ATTITUDE UNTIL REACHING AN ALTITUDE AT WHICH THE PILOT FLARED THE AIRPLANE FOR LANDING. AFTER LANDING IN THE WATER THE AIRPLANE NOSED OVER AND SANK. THE ON-SCENE INVESTIGATION REVEALED THE TURBOPROP ENGINE'S COMBUSTION CHAMBER HAD RUPTURED AND THAT IT DID NOT HAVE A NEGATIVE TORQUE SENSING SYSTEM THAT WOULD ALLOW THE PROPELLER TO FEATHER WHEN THE ENGINE FAILED. THE AIRPLANE WAS NOT EQUIPPED WITH A MANUAL PROPELLER FEATHERING SYSTEM.

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

THE PROPELLER NOT BEING ABLE TO BE FEATHERED BY THE PILOT, INADEQUATE ALTITUDE FOR A SUCCESSFUL FORCED LANDING, AND THE FAILURE OF THE COMBUSTION SECTION. A FACTOR ASSOCIATED WITH THIS ACCIDENT WAS THE STALL/MUSH ENCOUNTERED BY THE PILOT DUE TO THE WINDMILLING PROPELLER'S DISC DRAG AND RAPID DECELERATION OF THE AIRPLANE.

Full narrative available

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