On March 10, 1988, a Bell 206B (registration N13Q) operated by Helicopters, Inc. was involved in an aviation accident near Cahokia, IL. Investigators recorded the probable cause as: The pilot prematurely added full power during startup, causing the helicopter to rotate rapidly to the right. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 9 related events involving the same aircraft type or operator are linked below.
During a helicopter employment evaluation, the pilot prematurely added full power, causing a rapid right rotation. The tail rotor struck a tractor attached to the trailer, and the main rotor assembly separated.
Incident Overview
An instructor was conducting an employment evaluation for a pilot in a helicopter. The helicopter was positioned on a trailer during the evaluation.
Sequence of Events
During the startup procedure, the pilot prematurely applied full power. This caused the helicopter to rotate rapidly to the right in an uncontrolled manner. The helicopter's tail rotor struck a tractor that was attached to the trailer during the rotation. Following the impact, the helicopter continued to rotate until the main rotor assembly broke away from the helicopter, after which it came to rest a few feet from the trailer.
Damage
The tail rotor struck the tractor, and the main rotor assembly separated from the helicopter. The torque gauge in the helicopter indicated a reading in excess of 100%.
Probable cause
The pilot prematurely added full power during startup, causing the helicopter to rotate rapidly to the right.