No fatalities

Helicopter Tail Boom Separates During Quick Stop Demonstration

Tucson, AZ, United States

On July 29, 2015, an AIRBUS AS350-B2 operated by US DEPARTMENT OF HOMELAND SECURITY was involved in an aviation accident near Tucson, AZ. No fatalities were reported. Investigators recorded the probable cause as: 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. This summary draws on records from NTSB; 4 related events involving the same aircraft type or operator are linked below.

SourcesNTSBPrimary reportUpdated 1785761257Data APIEditorial standards

During a quick stop demonstration, a helicopter's skids impacted the ground hard, leading to tail boom separation and subsequent ground spin. Both pilots reported no pre-impact mechanical issues.

Accident Details

The accident occurred while a flight instructor (CFI) was demonstrating a maneuver to a pilot-rated student. According to the operator's report, the CFI was demonstrating the flare portion of an autorotation when the aircraft continued through the power recovery point and impacted the runway. However, during interviews, both pilots clarified that the term "flare portion" referred to the quick stop maneuver, which was the maneuver being performed at the time.

Sequence of Events

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 and 75 feet above ground level. While hovering over the runway numbers facing the runway heading, the CFI described the intricacies of the quick stop maneuver. He specified that the maneuver would terminate to a hover and initiated the demonstration by accelerating to an airspeed of 65 knots.

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

Post-Impact Actions

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. It 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, completing two full circles while on the ground, before coming to a stop.

Damage and Mechanical Condition

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.

Contributing factors

Instructor/check pilotAltitude — Not attained/maintained