Sunday, February 5, 2017

Aerospatiale AS 350B2 AStar, United States Department of Homeland Security, N6095U: Accident occurred July 29, 2015 in Tucson, Pima County, Arizona

Aviation Accident Final Report - National Transportation Safety Board: https://app.ntsb.gov/pdf 

Docket And Docket Items -   National Transportation Safety Board: https://dms.ntsb.gov/pubdms

Aviation Accident Data Summary  -  National Transportation Safety Board:  https://app.ntsb.gov/pdf

US DEPARTMENT OF HOMELAND SECURITY: http://registry.faa.gov/N6095U

NTSB Identification: GAA15CA204
14 CFR Public Aircraft
Accident occurred Wednesday, July 29, 2015 in Tucson, AZ
Probable Cause Approval Date: 12/03/2015
Aircraft: AIRBUS AS350-B2, registration: N6095U
Injuries: 1 Minor, 1 Uninjured.

NTSB investigators used data provided by various entities, including, but not limited to, the Federal Aviation Administration and/or the operator and did not travel in support of this investigation to prepare this aircraft accident report.

According to the Pilot/Operator Aircraft Accident Report, the operator reported that, the flight instructor(CFI) was demonstrating the flare portion of an autorotation to the pilot-rated student when the aircraft continued through the power recovery point and impacted the runway. However, during the interview with the CFI and the student, both pilots referred to "flare portion" as the quick stop maneuver, which was the maneuver being performed at the time of the accident.

Both pilots stated that they hover taxied to the approach end of the runway, stopped over the runway numbers and established a hover between 65-75 feet above ground level. They reported that they hovered over the runway numbers, facing in the direction of the runway heading, and the CFI described the intricacies of the quick stop maneuver. The CFI specified that the maneuver would terminate to a hover, and initiated the quick stop demonstration by accelerating to the airspeed of 65 knots. 

The CFI reported that as he talked through the maneuver, he lowered the collective and applied aft cyclic. He stated that as the helicopter began to settle, he misperceived the helicopters altitude in relation to the ground and the helicopter skids impacted the ground hard. Both pilots stated that the CFI responded by increasing collective and the helicopter ascended, started moving aft, and the tail boom separated impacting the left side of the fuselage. The student reported that he and the CFI were both on the controls after the first impact. 

Both pilots recalled lowering the collective in order to set the helicopter down, the helicopter remained in a level pitch attitude, but yawed left and landed on the skids. The helicopter remained on the ground as the left yaw continued, and the engine was shut down. Both pilots reported that the helicopter spun on the skids, in two complete circles while on the ground, before coming to a stop. 

The tail boom and main rotor system sustained substantial damage. 

Both pilots reported that there were no pre-impact mechanical malfunctions or anomalies with any portion of the helicopter that would have prevented normal operations. 

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
The flight instructor's misperception of the helicopter's altitude in relation to the runway surface during a low altitude maneuver, resulting in ground impact.

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