Aviation Accident Summaries

Aviation Accident Summary FTW99TA190

HOUSTON, TX, USA

Aircraft #1

N7491F

Hughes 269C

Analysis

During a night instructional flight, the helicopter landed hard during a practice autorotation following a simulated engine failure during takeoff. The operator stated that the toe of the right landing gear skid sank into the ground, and the helicopter made a 90 degree turn. The main rotor blades made contact with and severed the tailboom of the helicopter. The operator reported that the maneuver was entered below the recommended airspeed of 60 knots, and consequently a high rate of sink developed during the landing flare, which the pilot receiving instruction was unable to arrest. No mechanical malfunction or failure was reported by either the pilot or the operator.

Factual Information

On July 14, 1999, at 2151 central daylight time, a Hughes 269C helicopter, N7491F, was substantially damaged during a hard landing at the Houston Hobby Airport (HOU), near Houston, Texas. The flight instructor was not injured and the commercial pilot receiving instruction sustained minor injuries. The helicopter was owned and operated by the Houston Police Department. Night visual meteorological conditions prevailed for the Title 14 CFR Part 91 instructional flight for which a company flight plan was filed. The flight originated from the Houston Hobby Airport about 30 minutes prior to the accident. According to personnel at the airport, the helicopter was conducting night training operations as part of the night check out for the 281-hour pilot receiving instruction. The helicopter had been cleared by Houston Hobby Control Tower to maneuver in the grassy area between Taxiway Golf and Runway 17, located on the west side of the airport. The scheduled night check-out was the final phase in the pilot's training prior to being signed-off as pilot-in-command during operational missions. The scope of the check-out covered all normal and emergency operations, including full touchdown and power recovered autorotations. Simulated engine failures were initiated in all phases of the flight, to include simulated engine failures on takeoff, hovering autorotations, straight-in autorotations, 180-degree turn autorotations, and 90-degree turn autorotations. The operator reported that a total of 12 autorotations had been satisfactorily completed during the flight. The last maneuver to be evaluated was the simulated engine failure during takeoff. This maneuver was to be initiated by the flight instructor after the helicopter had attained a minimum airspeed of 60 knots, and a minimum altitude of 50 feet agl. The maneuver was performed satisfactorily once. In a telephone interview, the operator reported that during a second simulated engine failure during takeoff, the helicopter landed hard, the toe of the right landing gear skid sunk into the ground, and the helicopter made a 90-degree turn. The operator added that the maneuver was initiated slightly below the recommended airspeed of 60 knots, which contributed to a high rate of descent developing, which the pilot was unable to arrest during the landing flare. The main rotor blades came in contact with the aft fuselage, severing the tailboom. The right rear landing strut collapsed; however, the helicopter remained in the upright position. No mechanical malfunction or failure was reported by either the pilot or the operator. The FAA inspector, who responded to the accident site, confirmed that the airframe and tailboom of the helicopter sustained structural damage. A review of the helicopter's maintenance records by the FAA inspector did not reveal any evidence of overdue inspections or uncorrected discrepancies that could have contributed to the accident.

Probable Cause and Findings

The hard landing as a result of the flight instructor's failure to attain the proper airspeed before simulating an engine failure, which resulted in the development of a high sink rate. Factors were the night illumination and the soft ground.

 

Source: NTSB Aviation Accident Database

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