FTW93FA137
FTW93FA137

HISTORY OF FLIGHT:

On April 23, 1993, at approximately 1447 central daylight time, near Austin, Texas, a Bell 206B III helicopter, N2205X, was destroyed during an uncontrolled descent when it impacted trees and terrain. The helicopter rated private pilot who was also the owner and operator of the helicopter sustained fatal injuries. The non helicopter commercial pilot rated passenger also received fatal injuries. Visual meteorological conditions prevailed for the personal flight.

During interviews, conducted by a Federal Aviation Administration inspector and the investigator in charge, with airport personnel, other pilots and witnesses, the information in this paragraph was revealed. The owner (operator) arrived at the Robert Mueller Airport, Austin, Texas, at approximately 0900 on the day of the flight and began seeking a pilot to fly with him in the helicopter. The owner (operator) located a pilot to fly with him; however, this pilot did not have any helicopter experience.

Further personal and telephone interviews with the witnesses, by the Federal Aviation Administration inspector and the investigator in charge, revealed the information in this paragraph. Written witness statements also contributed to the information. The helicopter was observed maneuvering in the vicinity of Horseshoe Bay, Texas, and Austin, Texas, areas. One witness observed the helicopter in a descent approaching to the west to approximately 20 feet above the ground and within approximately 30 seconds the helicopter started rotating counterclockwise and climbing. A group of five witnesses observed the helicopter in a descending approach to the east to approximately four feet above the ground and within seconds the helicopter started rotating counterclockwise and climbing. Witness estimates of the climb altitude of the helicopter included 200 feet, 400 feet, 500 feet, and 800 feet above the ground. The helicopter then started descending and continued rotating until it hit the ground, approximately one fourth mile from the approach area, and started burning. Winds in the area were described as from the south variable from the southeast with gusts estimated in excess of 30 knots.

PERSONNEL INFORMATION:

Interviews, conducted by the investigator in charge, with personnel of the company selling the helicopter revealed the following information. The pilot had owned 14 Bell helicopters from said company from 1983 through 1990. Company personnel did not have knowledge of the pilot having accomplished takeoffs, landings, or maneuvers, in a Bell helicopter since January, 1990. During April, 1993, a company pilot made two local flights with the private pilot in a Bell 206. During those flights, the private pilot manipulated the controls during the enroute phase. On April 22, 1993, the same company pilot flew a local acceptance flight of approximately five minutes in N2205X. During that flight, the private pilot did not manipulate the controls. The pilot purchased N2205X on April 9, 1993.

A review of the private pilot logbooks revealed that the pilot had logged 1,042 hours of pilot in command flight time in a Bell 206 prior to 1982. Logbooks since that date were not made available to the investigator in charge. His last medical certificate was issued on February 2, 1982.

Interviews conducted by the investigator in charge with the pilot who flew a Bell 206 with the owner from October, 1986, to January, 1990, revealed the following information. Prior to 1986, the owner had owned and operated several Bell helicopters with an estimated flight time of 300 hours as manipulator of the controls. During that time frame, he operated with another pilot in the helicopter. From 1986 to 1990, the owner was estimated to have flown 250 hours, during which time he often maneuvered the helicopter, but was not known to have logged pilot in command time. There was no knowledge of the pilot having flown since 1990.

Enclosed statements from pilots at Austin, Texas, revealed the following information. On the morning of April 23, 1993, the owner was looking for a pilot to fly with him in N2205X. He informed one of the pilots that he did not have a medical certificate and offered to teach him how to fly the helicopter. He informed another pilot that he was looking for a helicopter pilot and that any interested party would be trained in the Bell at the owner's expense.

WRECKAGE AND IMPACT INFORMATION:

The accident site was in an area of rolling hilly terrain with scrub brush approximately two feet tall and cedar junipers approximately 15 feet tall. The impact zone was, approximately one fourth mile from the approach field, at the base of an approximately seven foot and 45 degree slope. Ground scars, the approximate length of the skids, were noted in the terrain. The helicopter came to rest on a measured magnetic heading of 040 degrees. Trees along the descent path were not damaged. One tree approximately 15 feet tall and located approximately four feet to the east of the tail boom had numerous broken branches from the top of the tree to the ground. Examination by a materials engineer indicated the rivets on the tail rotor blades contained fiber material and the surface of the blades contained brownish smears associated with vegetation. A green navigation lens was located at the base of the tree branches. A ground scar, containing grass and tree branches, the approximate length and width of the horizontal stabilizer tip, was located approximately four feet to the west of the tree. Both horizontal stabilizers were examined and the left horizontal showed impact damage and embedded grass. Another tree approximately six feet northeast of the main wreckage had tree branches cut approximately two feet above ground level. A ground scar, approximately the width of the main rotor blade, was located to the east of the tree. Fuselage cockpit and cabin areas were destroyed by a post crash impact fire. The main rotors remained intact and the areas not destroyed by fire, exhibited dents and striations.

All structural and control components were melted or reduced to ashes. Control rod ends contained nuts and cotter pins. All fuel tanks and system components were destroyed. Dual cyclic and collective controls were located. The right seat collective exhibited bending and the right seat cyclic was displaced forward. The throttle was positioned between midrange and flight idle.

The transmission and main rotor drive was intact and mounted in the pylon links. Hydraulic and oil pumps drives and splines were intact. The main driveshaft was intact. A disassembly of the freewheeling unit did not reveal any discrepancies. The input linkage was intact on each side of the hydraulic servo.

Continuity was established for the main rotor.

The tail rotor drive shaft system was intact from the 90 degree gearbox forward to the tail boom attachment point. The steel section of tail rotor driveshafting beneath the engine exhibited a torsional overload fracture. Forty five degree angle torsional wrinkles were in the shaft at the fracture area. The material engineer found impact forces crushing and bending the tail rotor driveshaft. Hand rotation of the remaining tail rotor driveshaft system revealed rotation of the complete system.

The engine fuel control pointer position was at 90 degrees and the PC tube and filter was intact.

MEDICAL AND PATHOLOGICAL INFORMATION:

The autopsy was performed by the Breckenridge Hospital, located in Austin, Texas. Toxicological findings were negative.

TEST AND RESEARCH:

The turbine, compressor, fuel nozzle, and the remaining portions of the gearbox were disassembled on April 29, 1993. The fuel nozzle was flow tested without discrepancies. Turbine and compressor components did not reveal any anomalies. A summary of that inspection is enclosed.

Metallurgical examination (report enclosed) of the governor drive gear revealed a fracture plane inclined to the transverse plane representative of overstress separations.

Energy dispersive spectral analysis of particles (report enclosed from the magnetic plug produced two basic spectra of iron and magnesium.

Examination of the fuel control unit components not destroyed by fire, did not reveal any assembly discrepancies. The governor bellows measured within limits per overhaul instructions. The report is enclosed.

Various tail rotor drive components were examined on June 2, 1993. That report is also an enclosure.

ADDITIONAL DATA:

Helicopter components, excluding the engine, governor, and gearbox accessories were released to the brother of the widow on April 25, 1993. The retained components were released to the owner's representative following the completed investigation.

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