Aviation Accident Summaries

Aviation Accident Summary FTW94LA221

MOUNTAIN VIEW, AR, USA

Aircraft #1

N39WL

BELL OH-13E

Analysis

A HELICOPTER WITH A 1 HOUR AND 45 MINUTE RANGE DEPARTED WITH A FULL TANK OF FUEL ON A PERSONAL CROSS COUNTRY FLIGHT. A POWER LOSS OCCURRED SHORT OF THE DESTINATION AIRPORT, 65 MINUTES AFTER DEPARTURE. AN AUTOROTATION WAS INITIATED TO A CLEARING IN A ROCK PIT. THE PILOT ALLOWED THE ROTOR RPM TO DECAY WHILE ATTEMPTING TO CLEAR A FENCE ACROSS HIS TOUCHDOWN AREA. DURING LANDING, A MAIN ROTOR BLADE MADE CONTACT WITH THE TAILBOOM. DEBRIS WAS FOUND BLOCKING THE FUEL DRAIN VALVE FOR THE FUEL TANK IN THE OPEN POSITION, ALLOWING FUEL TO DRAIN WHILE EN ROUTE. THE DENSITY ALTITUDE WAS 2,200 FEET.

Factual Information

On July 3, 1994, at 1050 central daylight time, a Bell OH-13E helicopter, N39WL, was substantially damaged during a forced landing near Mountain View, Arkansas. The private pilot was not injured. Visual meteorological conditions prevailed for the personal flight. According to the pilot, the aircraft was in cruise flight at 1,650 feet MSL when the engine lost power. The pilot added that he established an autorotative descent to a gravel pit, and during the landing flare, he was forced to stretch the glide to clear a fence. One main rotor blade struck and severed the tailboom. Records indicate that the 29 gallon fuel tank in the helicopter was topped off with 16.1 gallons of 100LL AVGAS prior to departure from the North Little Rock Airport at 0945. The loss of power occurred after 65 minutes of flight had elapsed. The estimated fuel consumption rate for the helicopter is 16 gallons per hour. A post accident inspection of the helicopter revealed that the fuel tank was empty. According to the pilot, debris was found in the fuel drain valve for the fuel tank and the valve may have been stuck in the open position, thereby allowing the fuel to leak out while the helicopter was en route.

Probable Cause and Findings

THE FUEL EXHAUSTION AS RESULT OF A STRUCK FUEL DRAIN VALVE. FACTORS WERE THE HIGH DENSITY ALTITUDE, AND THE UNSUITABLE TERRAIN AT THE PILOT'S DISPOSAL FOR THE FORCED LANDING.

 

Source: NTSB Aviation Accident Database

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