19961128036749A

Tail rotor chip lite on. Vibration. Lost tailrotor control hit rig. Landing pitch change links broke. (-23) on November 28, 1996, at approximately 1537 central standard time, a Eurocopter AS350B2, N6100U, owned and operated by petroleum helicopter, inc., (phi) as a title 14 CFR, part 135 flight, was destroyed during an emergency landing at the high island A20 platform in the gulf of Mexico. Visual meteorological conditions prevailed, and a company VFR flight plan was filed for the on demand air taxi flight. The air transport rated pilot and two passengers were fatally injured. The flight had departed high island 446, gulf of Mexico at approximately 1504, with a destination of high island 105. The operator reported the following information: the pilot had radio contact with company flight following located at Galveston, Texas. The pilot reported a tail rotor gearbox "chip light" and a vibration. The vibration decreased when power was reduced. The pilot reported he had made an attempt to land on high island A20 platform but was having trouble with loss of some tail rotor control. He was making another attempt to land on the platform whe n radio contact was lost. The phi base at Galveston launched an aircraft to high island 120 immediately after loss of radio contact. On arrival at the 120 platform, they found two bodies floating in the water face down and no aircraft. The persons found were the pilot and one passenger. The pilot's body had been severed approximately at the waist and the passenger had multiple compound fractures. There were no occupants on high island A20 platform at the time of the accident. No witnesses have been located. On examining high island A20 platform, a small amount of damage was found on top of a metal building approximately 15 feet below the raised heliport, and approximately 4 feet inboard from the outer edge of the platform. A small amount of metal springs and fiberglass pieces identifiable as parts of the aircraft fuselage were found on the same level as the damaged building on the platform. When the aircraft was located and recovered, from approximately 50 feet of water, the main rotor components were still identifiable and the outer shell of the cabin had been torn away. The third passenger was in the aircraft and had been riding in the left front seat. The tail boom had been severed apparently by a main rotor strike. The tail rotor gear box and tail rotor remained attached to the tail boom and the tail rotor blades sustained very little damage. One tail rotor pitch change link was broken approximately midway of the rod end bearing that attaches the link to the tail rotor blade pitch horn. The rod end bearing was still attached to the tail rotor blade. The tail rotor gear box contained some metal shavings. With some types of tai rotor malfunctions a run on landing would be required to minimize the risk of aircraft damage and personal injury. Other types of tail rotor malfunctions may require closing the throttle and entering autorotation. Most emergency landings with a tail rotor problem could not be safely conducted on an elevated, small heliport on an offshore platform.