NTSB Factual Report

HISTORY OF FLIGHT

On June 10, 1997, at 0938 hours Pacific daylight time, a North American-Rockwell OV-10A Bronco, N94LM, was destroyed when it impacted the side of a hill 25 statute miles southeast of Hollister, California, at GPS coordinates 36.34.0 degrees north latitude and 121.10.6 degrees west longitude. The commercial pilot was fatally injured, and several trees on the surrounding property were destroyed by fire. The flight departed from Meadows Field, Bakersfield, California, on a local training flight and was being operated by the Bureau of Land Management as a public-use aircraft. Visual meteorological conditions prevailed at the time and no flight plan had been filed.

Four witnesses from a fire station reported observing the aircraft fly by their location at approximately 200 feet agl and initiate a roll to the right. The aircraft continued the right roll to a near inverted attitude and then reversed the roll direction in an attempt to level the wings. The aircraft then struck the ground in approximately a 90-degree right bank attitude where it disintegrated and burned. The witnesses stated that the aircraft engines sounded normal and they did not observe anything depart from the aircraft prior to impact.

PILOT INFORMATION

The pilot had recently joined the Bureau of Land Management (BLM) as an OV-10 pilot. Prior to that time, he had been a helicopter pilot with the U.S. Forest Service and had worked at the fire station where the accident occurred.

The pilot's logbook indicated that he had a total of 10,063 flight hours, of which 7,926 were in helicopters and 1,837 in multiengine aircraft. Since joining the BLM, he had accumulated a total of 21 hours in the OV-10A. He held a commercial pilot certificate with single engine airplane, multiengine airplane, rotorcraft helicopter, instrument-airplane, instrument-helicopter, and helicopter instructor ratings. He also held a current Class 2 medical certificate with a requirement to possess glasses while piloting an aircraft.

AIRPLANE INFORMATION

Federal Aviation Administration (FAA) records indicated that the aircraft was a 1968 North American-Rockwell OV-10A powered by Garrett turboprop engines rated at 715 horsepower each. Aircraft records indicated a total airframe time of 11,152 hours. The aircraft was being maintained on a continuous inspection program and had 88 hours since the last inspection. The left engine, serial number GE00386, had a total time of 8,074 hours with 682 hours since the last overhaul. The right engine, serial number GE00687, had a total time of 6,416 hours with 894 hours since the last overhaul. There were no outstanding Airworthiness Directives (AD's) or recent major maintenance activity evident in the aircraft records.

METEOROLOGICAL INFORMATION

On-site witnesses reported that, at the time of the accident, the weather was clear and visibility 10 statute miles or better with a surface wind from 005 degrees magnetic at approximately 5 knots with no apparent wind gusts. The free air temperature was approximately 69 degrees Fahrenheit. Calculations performed by the Safety Board indicated that a density altitude of 2,200 feet msl existed at the time.

WRECKAGE AND IMPACT INFORMATION

The aircraft remains were found scattered over the west and north sides of a low hill. Ground scars and the wreckage were distributed on a median magnetic bearing of approximately 005 degrees. Witnesses stated that it appeared to them that the aircraft was in a 90-degree right bank and a 30-degree nose low attitude at the time of impact.

The airframe and engines were destroyed by the impact sequence and subsequent fire to the extent that preimpact continuity of the flight control system, engine controls, or fuel system could not be determined. In addition, none of the cockpit instruments or controls were usable for forensic purposes.

There were two debris fields, both oriented on the 005-degree magnetic bearing. The first consisted of approximately a 100-yards-long by 70-yards-wide field. The second began about 200 yards beyond the end of the first and continued for 100 yards with a width of 40 yards. Most of the heavy pieces of the airframe, such as the engines and landing gear, were located in the second debris field. Both engine compressors sections were located in the second debris field and displayed rotational damage. Both propellers were in the first debris field and had forward bending of all blades with deep chordwise scratches on the flat side of the blades. One prop blade from the left engine had departed from the hub and was found imbedded in a tree approximately 50 yards to the left and 30 yards forward of the initial impact point.

MEDICAL AND PATHOLOGICAL INFORMATION

The toxicology report received from the FAA Civil Aeromedical Institute (CAMI) was negative for carbon monoxide, ethanol, and drugs. Cyanide analysis could not be performed due to lack of a suitable specimen.

ADDITIONAL INFORMATION

On June 11, 1997, the aircraft wreckage and all airframe and engine records were released to the Office of Aircraft Services, Department of Interior, Boise, Idaho. No components were retained by the Safety Board.

NTSB Probable Cause

the pilot's failure to maintain adequate ground clearance altitude while performing a low-level aerobatic maneuver. A factor in the accident was the pilot's lack of experience in the aircraft.