Casualties unknown

Helicopter Roll During Simulated Hydraulics Failure Training (N211PD)

Islip, NY, US

On August 3, 1999, an Eurocopter AS-350 (registration N211PD) was involved in an aviation accident near Islip, NY. Investigators recorded the probable cause as: The pilot's loss of control during hydraulics-off hovering flight and the instructor's inadequate supervision of the maneuver. A factor was the tailwind. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 2026-06-10Data APIEditorial standards

A helicopter rolled during a hover taxi maneuver with hydraulics disabled, causing main rotor blades to strike terrain. No pre-impact anomalies were found.

Accident Overview

A helicopter experienced a rollover during a training exercise involving simulated hydraulic system failure. The pilot, undergoing transition training with a flight instructor, had initiated the simulated failure out of sequence with the flight-training guide and landed without incident.

Sequence of Events

After landing with hydraulics still disabled, the instructor directed the pilot to hover-taxi approximately 100 feet, perform a left pedal turn, and then taxi back to the starting point. The pilot successfully completed the forward hover, but during the left pedal turn to return, control was lost. The instructor attempted to recover, but the helicopter rolled, and the main rotor blades struck the terrain.

Environmental Conditions

Following the turn, the helicopter's orientation resulted in a 14-knot tailwind. No other weather or time-of-day specifics were provided in the investigation.

Wreckage Examination

Examination of the wreckage revealed no pre-impact anomalies. The hydraulic servos were tested and showed high fluid flow rates, but no operational deficiencies were identified.

Subsequent Actions

Approximately one year after the accident, the helicopter manufacturer removed in-ground-effect maneuvers with the hydraulics off from their flight-training guide.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X19539. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.