Summary
On December 15, 2012, a Robinson R22 (N393LE) was involved in an incident near Logan, UT. All 2 people aboard were uninjured. The aircraft sustained substantial damage.
The National Transportation Safety Board determined the probable cause of this incident to be: The flight instructor’s delayed remedial action and inadequate supervision during a practice autorotation, which resulted in a failure to maintain adequate main rotor rpm. Contributing to the accident was the wet landing surface.
During the 180-degree autorotation the student maintained 65 knots with the rotor revolutions per minute (RPM) in the green. As the student rolled out of the turn at about 300 feet above ground level and at 70 knots, the rotor rpm continued to remain in the green. However, prior to the flare the rotor RPM began to decay and failed to build as the flare was entered. The flight instructor then took control of the helicopter and immediately rolled on throttle to recover engine [power] and to maintain [rotor] RPM, but there was insufficient engine power to recover the decayed rotor RPM; this was followed by a low rotor RPM light and horn. As power was not available for a full power on landing, the flight instructor initiated a full down autorotation to a taxiway.
This incident is documented in NTSB report WPR13CA068. AviatorDB cross-references NTSB investigation data with FAA registry records to provide comprehensive safety information for aircraft N393LE.
Accident Details
Probable Cause and Findings
The flight instructor’s delayed remedial action and inadequate supervision during a practice autorotation, which resulted in a failure to maintain adequate main rotor rpm. Contributing to the accident was the wet landing surface.
Aircraft Information
Registered Owner (Historical)
Analysis
During the 180-degree autorotation the student maintained 65 knots with the rotor revolutions per minute (RPM) in the green. As the student rolled out of the turn at about 300 feet above ground level and at 70 knots, the rotor rpm continued to remain in the green. However, prior to the flare the rotor RPM began to decay and failed to build as the flare was entered. The flight instructor then took control of the helicopter and immediately rolled on throttle to recover engine [power] and to maintain [rotor] RPM, but there was insufficient engine power to recover the decayed rotor RPM; this was followed by a low rotor RPM light and horn. As power was not available for a full power on landing, the flight instructor initiated a full down autorotation to a taxiway. During the landing the helicopter skidded across and off the wet taxiway into loose gravel and mud before the left skid dug into the ground. This resulted in the aircraft rolling over and coming to rest on its left side. The helicopter sustained substantial damage to its welded frames, firewall, and tail cone. The flight instructor reported no mechanical malfunctions or failures with the helicopter or flight controls that would have precluded normal operation.
Data Source
Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# WPR13CA068