FTW96FA136
FTW96FA136

HISTORY OF FLIGHT

On February 10, 1996, at 0700 central standard time, a Mbb BO-105, N126EH, was destroyed upon impact with the water while maneuvering. The helicopter departed from an offshore platform at Main Pass (MP) 265, in the Gulf of Mexico, en route to another platform at Mobile Bay (MB) 990. The flight was being operated by the Gulf Coast Division of ERA Aviation Inc., of Anchorage, Alaska, under Title 14 CFR Part 135 at the time of the accident. The helicopter failed to arrive at its planned destination and the aircraft was reported missing at 0930. A search was initiated by ERA and the US Coast Guard that continued for 6 days without success.

The aircraft was found on February 28, 1996 entangled in the shrimp net of a local shrimp boat. The instrument rated commercial pilot was found still secured in the pilot's seat with the seat belt and shoulder harness. His passenger was not with the aircraft and was found 6 days later, approximately 60 miles to the southwest. Instrument meteorological conditions prevailed along the route of flight at the time of the accident.

According to the operator, the flight was scheduled to transport a mechanic to another off shore platform located 44 nautical miles to the northwest to repair a generator. The operator reported that the microwave repeater phone link relay system used to relay company flight plans was out of service at the time of the accident.

There were no reported eyewitnesses to this accident. The helicopter was equipped with emergency floats, a life raft, and personal floatation devices for the occupants.

PERSONNEL INFORMATION

The pilot held a commercial pilot certificate with rotorcraft-helicopter and instrument helicopter ratings. He had a current class one FAA medical certificate with a limitation requiring him to wear glasses for near and far vision that was dated October 11, 1995. He had been employed with ERA helicopters since October 2, 1988. His total fight time was approximately 11,288 hours, all of which were in helicopters. He had no history of previous accidents, incidents, or flight violations and his total experience in Gulf helicopter operations was more than 7 years (approximately 8,000 flight hours).

AIRCRAFT INFORMATION

The MBB BO-105, serial number S-567 had a current standard airworthiness certificate that was issued on October 19, 1995. The helicopter was acquired by ERA Aviation, Inc. in May of 1982. The aircraft was operated and maintained under their FAR 135.411(a)(1) Approved Aircraft Inspection Program (AAIP) since that time. It was exported briefly to Trinidad in July 1994, and returned in September 1995. During the time the aircraft was exported it was maintained by US certified persons and supported logistically by ERA Aviation from their certified repair station in Lake Charles, Louisiana. Airframe total time at the time of the accident was 10,596.3 hours.

A detailed review of the aircraft maintenance records indicated that all of the inspections required by the AAIP had been complied with. The last available record of maintenance was a daily service check that had been performed on February 8, 1996, two days before the accident. The last 50 hour inspection was performed on February 6, 1996, 8.0 flight hours prior to the accident.

Airworthiness Directive (AD) compliance was verified using the maintenance records and were visually inspected on the aircraft (during wreckage examination) for compliance. The non-applicable AD's were verified to be "non-applicable". All pertinent AD's were complied with and verified. A detailed review of the airframe maintenance records revealed no uncorrected defects or anomalies.

The helicopter was powered by two Allison 250-C20B turbo shaft engines. Engine #1 (left side), serial number CAE-834445, had a total operating time of 9,894.2 hours. It was installed on the airframe on June 21, 1992. Engine #2 (right side), serial number CAE-836474, had a total operating time of 3427.1 hours. It was installed on the airframe on April 14, 1994. A review of both engines' maintenance records revealed that all overhauls and inspections of the accessory, gearbox, compressor, and turbine sections were properly complied with, and no anomalies or uncorrected defects were found.

METEOROLOGICAL INFORMATION

The lead operator on MP 265 reported that with the exception of a fog bank 3 to 4 miles to the west at the approximate time of takeoff, the weather at the point of departure as well as the intended destination was visual meteorological conditions (VMC).

COMMUNICATIONS

There was a reported radio outage on Venice frequency 130.265 MHz prior to 0730 on the morning of February 10, 1996. No radio contact for flight planning or flight following was established from the pilot, and no distress calls were reported.

WRECKAGE IMPACT INFORMATION

The aircraft was drug by a shrimp boat for nearly sixty miles prior to being recovered to shore. The entanglement of the shrimp net and the distance covered before removal from the water may have caused additional damage to the aircraft structures.

The major components of the helicopter that were recovered were the fuselage, powerplants, main transmission, hydraulic pack, main rotor hub assembly, flight controls, tailboom, and tailrotor drive shaft. All four main rotor blades were broken at the hub assembly root and were not recovered. The cabin area from the chin bubbles to the overhead console and cabin roof were separated and not recovered. The pilot's floor, flight controls, seat, seat belt, and shoulder harness were intact. The left front passenger seat from the center console area outboard had also separated and was not with the fuselage.

Cockpit instrumentation, switch positions, and circuit breaker positions were not possible to verify. Due to the length of time that the aircraft was in the water and the entanglement of the shrimp net, the flight and engine instruments were destroyed.

Flight control continuity was confirmed by the investigator-in-charge and showed no evidence of pre-existing problems.

The nose portion of the underside and the belly was crushed inwards and aft. The skids were found separated in an upward and aft direction. Crushing damage to the nose of the helicopter was symmetrical. All main rotor blades were separated at the main rotor hub. Deformation signatures throughout the structure and dynamic components showed evidence that the aircraft impacted the water with a high rate of airspeed, near level pitch attitude, and slightly right skid down.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy was performed by the Medical Examiner's Office for Jackson County, Pascagoula, Mississippi. Toxicological findings were negative.

TESTS AND RESEARCH

Both engines were examined by the NTSB at the manufacturer's facility on March 21, 1996. No pre-mishap discrepancies were observed. See enclosed report for examination details.

The Tandem Hydraulic Unit (THU) serial number 2042, was sent to Eurocopter Deutschland's (ECD) hydraulic laboratory in Ottobrunn, Germany for testing. According to the investigation report provided by ECD, there were no indications that would give reason to doubt the proper function of the Tandem Hydraulic Unit at the time of the accident.

ADDITIONAL DATA

The wreckage and all components that were tested were released to the owner.

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