NTSB Factual Report

HISTORY OF FLIGHT

On May 10, 1994, approximately 0815 central daylight time, a Bell 206L-3 helicopter, N5844, was destroyed near Intracoastal City, Louisiana, when it impacted the water in an uncontrolled descent. The airline transport rated pilot and four passengers received fatal injuries. Visual meteorological conditions prevailed for the company Title 14 CFR Part 91 flight.

According to Toca New Orleans (flight following) records, the pilot's route of flight was from Acadiana Regional Airport (ARA), Erath Helistop (LA70), then to Vermillion 149 in the Gulf of Mexico. The operator reported that the helicopter was the third aircraft to depart Erath helistop en route to Vermilion 149 for crew change. At 0830 a radio call was made to the pilot to coordinate the crew change at Vermillion 149. There was no response. At 0845, 5 minutes after his ETA, a formal radio search was started.

A search along the intended route of flight towards the beach commenced at 0850. The helicopter was located at 0927 approximately one mile from shore.

PERSONNEL INFORMATION

The airline transport rated pilot accumulated 2,776 hours of flying in the vicinity and over the Gulf of Mexico while being employed by Petroleum Helicopters, Inc., and Southern Natural Gas.

The pilot completed VFR and IFR refresher training at the Bell Helicopter Customer Training Academy on April 19, 1994. See the enclosed training record.

AIRCRAFT INFORMATION

A review of the airframe and engine records did not reveal any anomalies or uncorrected maintenance defects. An estimate of the weight of the helicopter at the time of the accident placed the helicopter within its weight and balance limits.

WRECKAGE AND IMPACT INFORMATION

The helicopter was located south of Intracoastal City, Louisiana, approximately one mile off shore in the Gulf of Mexico at latitude 29 degrees 34.4 minutes north and longitude 92 degrees 08.9 minutes west. All aircraft major components were located within 100 feet radius of the wreckage. Numerous light pieces of the aircraft floated to the nearby shore.

The section from the cabin nose to the bulkhead behind the cargo and passenger compartment was separated from below the transmission deck to the baggage compartment. The pitot tube was bent down and aft. The skids were separated from the fuselage, and the floats were not inflated.

The main rotor blades remained attached to the main rotor blade grip/hub assembly. There was no evidence of mast bumping. The transmission input coupling driveshaft assembly was fractured and the shaft was bent.

The tail rotor gear box and vertical stabilizer were separated from the tail boom. The bottom half of the vertical stabilizer was split apart. The tail boom just forward of the horizontal stabilizer was buckled on the bottom side and the skin was torn. The five tail rotor drive shaft segments were still attached to the oil cooler fan shaft and tail boom. There were markings on top of the left horizontal stabilizer that corresponded to marks on the bottom of one main rotor blade.

MEDICAL AND PATHOLOGICAL INFORMATION

The autopsy was performed by Emil M. Laga, M.D., New Iberia, Louisiana. There was no evidence of any preexisting disease that could have contributed to the accident. Toxicological findings were negative.

TEST AND RESEARCH

During a reconstruction of the helicopter at Air Salvage of Dallas, in Lancaster, Texas, on May 16, 1994, a metallurgist from Bell Helicopter-Textron, by direction, examined fractured surfaces of components, and concluded they were the result of overload forces. Flight control continuity was established to all flight controls.

A disassembly inspection of the Allison Model 250-C30P, S/N 895528 gas turbine engine, at Aviall, Inc, in Dallas, Texas, on July 5, 1994, did not reveal any anomalies that would contribute to the accident. Evidence of engine rotation at impact was denoted by rubbing contact between the compressor impeller (centrifugal) and the stationary compressor shroud. Additional rotational indications were evidenced by rub contact between the shrouded tips of the third and fourth stage turbine blades and their respective blade paths. Metallurgical evaluations at Allison Engine Company, in Indianapolis, Indiana, of the No. 8 nozzle shield, first stage turbine nozzle, and first and second stage turbine wheel did not reveal evidence of aluminum splatter.

A disassembly inspection of the Bendix fuel control, S/N BR52711 and the Bendix power turbine governor, S/N BR37064, at Bendix Engine Controls, South Bend, Indiana, did not reveal any significant anomalies.

ADDITIONAL INFORMATION

The helicopter wreckage was released to the operator.

NTSB Probable Cause

THE PILOT'S FAILURE TO MAINTAIN AIRCRAFT CONTROL FOR UNDETERMINED REASONS.