Aviation Accident Summaries

Aviation Accident Summary CHI96LA032

CRYSTAL, MI, USA

Aircraft #1

N58231

HUGHES 369D

Analysis

The helicopter was approximately 50 feet above the ground lifting a load of trees when its engine lost power. The pilot attempted autorotation. The helicopter's right skid collapsed on impact with the terrain rolling the helicopter on its side. A witness observed 'black smoke around the ship' as the helicopter descended. Examination of the wreckage at the site revealed fuel to the fuel control, but no fuel in the line from the fuel control to the nozzle. There was approximately 150 pounds of jet fuel in the fuel tank. About ten drops of water were collected from the fuel sump screen. Examination of the nurse truck fuel supply at the site indicated that a filter at the pump was installed at an incorrect angle allowing water to collect in the sump. An examination of the engine at the factory revealed no mechanical anomalies.

Factual Information

On November 9, 1995, at 1515 eastern standard time (est), a Hughes 369-D, N58231, piloted by a commercial pilot, sustained substantial damage when while lifting a load of trees the helicopter's engine lost power. The helicopter subsequently impacted the terrain and rolled onto its side. Visual meteorological conditions prevailed at the time of the accident. The flight was conducted under 14 CFR Part 133. A flight plan was not on file. The pilot reported no injuries. The helicopter was on a local flight which originated at Crystal, Michigan, at 1415 est. The pilot reported that he was lifting a load of trees and moving them toward a truck. He was approximately "50 feet above the ground when the helicopter's engine quit." The pilot attempted autorotation, "but there was not enough inertia within the rotor system to sustain a soft landing." The right skid collapsed on impact with the terrain rolling the helicopter on its side. A witness at the scene reported hearing the helicopter's engine "shutting down." He observed "black smoke around the ship" as the pilot began to "nose the helicopter forward in an attempt to autorotate." The Federal Aviation Administration (FAA) inspector who examined the wreckage at the site found the helicopter resting on its side in a cleared field. Four of the five main rotor blades showed evidence of impact damage. A gash was found in the tail boom at fuselage station 242. The right skid had collapsed under the right side of the fuselage. The struts had fractured and the right skid tube had separated. Examination of the fuel system showed evidence of fuel from the pump to the fuel control. There was no evidence of fuel in the line from the fuel control to the nozzle. There was appoximately 150 pounds of jet fuel in the fuel tank. Water was found in the helicopter's fuel strainer. About ten drops of water were collected from the fuel sump screen. Continuity of the engine gearbox and overrun clutch was confirmed. Examination of the nurse truck fuel supply at the site indicated that a filter at the pump was installed at an incorrect angle allowing water to collect in the sump. The engine was examined at the Allison-National Air Motive facility in Oakland, California, on November 21 and 22, 1995, under the direction of an FAA inspector. Three engine tests were conducted. During the second test, the engine flamed out while accelerating on the start schedule. A third test was conducted under the same conditions. The engine accelerated normally. The flame out condition which occurred during the second test could not be duplicated. No other anomalies were found.

Probable Cause and Findings

fuel contamination resulting in the loss of engine power, and improper fuel sump screen installation on the nurse truck resulting in contamination of the fuel supply.

 

Source: NTSB Aviation Accident Database

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