On October 24, 2007, a Robinson R22 BETA (registration N7188S) operated by Los Angeles Helicopter was involved in an aviation accident near Long Beach, CA. Investigators recorded the probable cause as: The student pilot incorrectly reduced the throttle instead of increasing it during the low rotor rpm recovery maneuver. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A certified flight instructor and student were practicing low rotor rpm recoveries when the student pilot incorrectly reduced the throttle, causing the tail rotor to strike the ground and shear off its blades.
Accident Details
A certified flight instructor (CFI) and a student pilot were conducting low rotor rpm recovery practice in a helicopter. The CFI had instructed the student to execute the recovery when the low rotor rpm warning system activated, which included both a light and a horn. Prior to the maneuver, the CFI demonstrated and verified that the student understood the recovery procedure: lower the collective and increase the throttle.
The helicopter was in a 10-foot hover when the CFI decreased the rotor rpm by reducing the throttle until the low rpm warning system activated. The student pilot responded by lowering the collective and reducing the throttle instead of increasing it, contrary to the demonstrated procedure.
As a result, the helicopter yawed to the left and descended towards the ground. The tail rotor collided with the ground, shearing off its blades. The helicopter then rotated on the ground. The CFI managed to slow the rotation and shut down the helicopter.
Probable cause
The student pilot incorrectly reduced the throttle instead of increasing it during the low rotor rpm recovery maneuver.