On May 23, 2005, a Robinson R22 BETA (registration N553SH) was involved in an aviation accident near Provo, UT. Investigators recorded the probable cause as: the dual student’s failure to maintain adequate rotor rpm and the inadequate supervision by the instructor. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During hover practice, a student pilot controlling the cyclic caused oscillations and drift; after a low rotor rpm warning, the instructor took controls but the helicopter struck terrain and rolled over, sustaining substantial damage.
Incident Sequence
A flight instructor and a student pilot were practicing hovering maneuvers. The student was controlling the cyclic. During the exercise, the helicopter began to oscillate and drift to the right. In response, the student applied more right cyclic. Shortly thereafter, the LOW ROTOR RPM warning sounded, prompting the student to release the controls. The instructor then took control of the helicopter and attempted to recover from the situation. However, the aircraft subsequently struck terrain and rolled over.
Damage
The accident resulted in substantial damage to the helicopter. Specific damage items included a severed tail boom, a shattered windscreen, a buckled rotor mast, and wrinkled skin on the airframe.