Factual Report: Longranger Breaks Up on Oil Rig
Bell 206L-1 LongRanger, Galliano, La., March 13, 2005–LongRanger N480RA was destroyed when it crashed into the Gulf of Mexico when departing an offshore oil rig platform. The commercial pilot, the sole occupant, was seriously injured.
The pilot had just dropped off two passengers at the South Timbalier Block 220 and was headed to another rig, South Timbalier Block 161 (ST161), to refuel. Another helicopter landed at ST161 so the pilot returned to the first rig. With the rpm at ground idle, he waited about 10 minutes, then looked down to make an entry in the flight manifest. He felt the helicopter “rocking backwards.” He grabbed both controls, in an effort to “level” the helicopter, and lifted up on the collective and pushed forward on the cyclic. He said he “may” have attempted to increase the power.
A witness on a lower tier of the platform heard a “crunching” noise and saw the main fuselage falling over the side of the platform in a 45-degree nose-down attitude. The tailboom was separated from the fuselage.
A 1984 Bell Helicopter Operations Safety Notice said that “the tailboom and aft fuselage can be damaged if during an autorotation landing the main rotor rpm is allowed to decay below 70 percent. Applying collective pitch in excess of that required will in some instances result in excessive flapping of the main rotor during or after touchdown. This can cause a resonant response that can damage the tailboom and/or aft of the fuselage. Touchdown rotor rpm above 70 percent is preferred. Upon ground contact, collective pitch should be reduced smoothly without delay while maintaining cyclic pitch near the center position. Long ground runs with the collective up, or any tendency to float for a long distance prior to skid contact, should be avoided.”
When asked how the accident could have been prevented, the operator said, “Pilot should have remained more vigilant in monitoring control input and position. More aggressive use of control friction would have minimized the possibility of this occurrence.”
The pilot had a commercial certificate with airplane single-engine land, rotorcraft-helicopter and instrument helicopter ratings. He had 1,429 hours in helicopters and 106 hours in make and model.