Flight Details
A pilot was approaching an oil rig when he reduced power to begin a descent from 500 feet. At that point, the tail rotor (T/R) pedals began to vibrate. The vibrations intensified as the pilot further reduced power to decrease airspeed.
Pilot Actions
In response, the pilot planned a descent that would keep the helicopter closer to the water surface, anticipating a possible complete tail rotor failure. However, before the pilot could arm the automatically actuated emergency flotation bags, the helicopter unexpectedly struck the water.
Post-Impact Events
Upon water impact, the helicopter immediately rolled over. The main rotor assembly, tail rotor assembly aft of the 42-degree gearbox, vertical fin, and upper transmission were not recovered following the accident.
Regulatory Note
The investigation revealed that the operator did not hold a Federal Aviation Regulation (CFR) Part 135 exemption that would have allowed single-pilot operation of a Bell 212 over water.