Aviation Accident Summaries

Aviation Accident Summary NYC94LA110

WAREHAM, MA, USA

Aircraft #1

N59400

BELL 47-G5

Analysis

THE PILOT WAS PERFORMING AN AERIAL RECONNAISSANCE OF THE AREA TO BE FERTILIZER, AT 35 FEET ABOVE THE GROUND AND AN AIRSPEED OF 40 MILES PER HOUR. AT THE COMPLETION OF THE TURN TO DOWNWIND THE ENGINE LOST POWER. THE PILOT LEVELED THE HELICOPTER AND ENTERED AUTOROTATION. THE HELICOPTER LANDED HARD AND THE MAIN ROTOR STRUCK THE TAILBOOM. BOTH FUEL TANKS WERE FOUND INTACT AND A TOTAL OF 20 OUNCES OF USEABLE FUEL WAS DRAINED FROM THE TANKS. THE HELICOPTER FLIGHT MANUAL DEPICTED THE COMBINATION OF 35 FEET AND 40 MPH AS AN AREA TO AVOID CONTINUOUS OPERATIONS IN.

Factual Information

On July 2, 1994, at 0940 eastern daylight time, a Bell 47G- 5A, N59400, operated by Wiggins Airways and piloted by Larry Helms, was substantially damaged during a forced landing to a cranberry bog in Wareham, Massachusetts. The pilot received minor injuries. Visual meteorological conditions prevailed and a flight plan had not been filed for the agricultural application flight operating under 14 CFR 137. The purpose of the flight was the aerial application of fertilizer onto a cranberry bog in Wareham, Massachusetts. The helicopter was operating from a landing pad in close proximity to the area to be sprayed. In the NTSB Form 6120.1/2 the pilot stated: "...Aircraft [fuel gauge] indicated 12 to 15 gallons of fuel... While performing the aerial reconnaissance of the bog I was to dust, I had just turned downwind at 35 feet altitude when the engine failed. I leveled the aircraft and entered autorotation. I was able to level the aircraft and decelerate before ground contact..." The pilot estimated that his airspeed at the time of the engine failure was about 40 miles per hour (MPH). According to a witness, he heard a change in the engine noise and observed the helicopter contact the ground and the main rotor strike the tailboom. The manager of Helicopter Operations for Wiggins Airways, stated in a letter that during an inspection of the helicopter after the accident, the fuel tanks were found to be "whole and unruptured." Further, fuel drained from both fuel tanks totaled 101 ounces, of which 20 ounces was useable. The Bell Helicopter Flight Manual for the 47G contains an Airspeed vs. Altitude Chart, used to depict altitude and airspeed combinations, where successful power off autorotations can be expected. The chart depicts the airspeed and altitude combination of 40 MPH and 35 feet in the area that is labeled, "Avoid continuous operation."

Probable Cause and Findings

The pilot's inadequate inflight planning which resulted in fuel exhaustion and the loss of engine power.

 

Source: NTSB Aviation Accident Database

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