ANC03GA020

The tundra tire-equipped airplane was being operated as a local, visual flight rules, public use, game management flight for the purpose of locating moose with data collection collars. According to the airplane's operator, a typical flight would require the pilot and observer to locate a collared moose, and then fly in the immediate vicinity of the moose to enable the equipment aboard the airplane to relay data from the moose's collar to a ground-based data collection site. There was no data transmission in progress at the time of the accident, however fresh moose foot prints were observed within 50 yards of the accident site. An on-site inspection of the airplane disclosed ground scars and crush lines on the airplane consistent with a near-vertical impact. The inspection disclosed no evidence of any preimpact mechanical anomalies with the airframe or engine, and a readout of data stored in the engine monitoring system installed on the airplane indicated that the engine had adequate fuel flow and combustion. The observer received head injuries in the accident, and was unable to provide any information about the accident.

History of flight

On December 19, 2002, about 1230 Alaska standard time, a tundra tire-equipped Aviat A-1B airplane, N57HY, sustained substantial damage following a loss of control while maneuvering, and subsequent in-flight collision with terrain, about 70 miles south of King Salmon, Alaska. The airplane was being operated by the US Department of the Interior, as a visual flight rules (VFR) public use local game management flight, for the purpose of locating collared moose. The airline transport pilot received fatal injuries, and the observer received serious injuries. The airplane departed King Salmon Airport, King Salmon, about 1000; VFR conditions prevailed, and company VFR flight following procedures were in effect.

During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on December 19, at 1710, a Federal Aviation Administration (FAA) regional operations specialist reported that an alert notice (ALNOT) had been issued for the accident airplane.

On December 20, about 1630, searchers located the wreckage of the accident airplane.

Personnel information

The pilot held an airline transport pilot certificate with ratings for airplane multi-engine land, single-engine land, and single-engine sea. The pilot was instrument rated. He was issued an FAA Second Class Medical Certificate on January 30, 2002, and according to FAA records, had accumulated about 10,500 total flying hours. The total number of hours he had accumulated in the make and model of the accident airplane are unknown.

Aircraft information

The accident airplane was a 2000 model year Aviat Husky, equipped with tundra tires. At the time of the accident, the airplane had accrued a total airframe and engine time of 538.7 hours. The airplane was equipped with a Vision Microsystem VM1000 engine monitoring system. According to the director of maintenance for the operator, there were no known mechanical anomalies for the airplane reported prior to the accident.

Communications

The pilot made a radio contact with his operations base on December 19, about 1145, as per operational policy, but failed to make a 1300 contact. The airplane was reported overdue/missing at 1500, and a search was initiated.

Meteorological information

On December 19, at 1235, the Automated Weather Observation Station (AWOS) at Egegik, Alaska, (located about 45 nm northwest of the accident site), reported few clouds at 4,500 feet, visibility 10 statute miles, temperature 1 degree C, dew point -3 degrees C, wind from 120 degrees at 23, gusting to 30 knots, and an altimeter of 29.61 inches of mercury.

Wreckage and impact information

The terrain where the accident occurred is an undulating tundra plateau with areas of muskeg. Elevations along the plateau vary 4 to 6 feet, and the plateau is bounded by washes 10 or more feet deep. Brush along the top of the plateau reaches a maximum height of about 3 feet. The tundra layer is several feet thick, and soft and springy to walk on. The area is less than 100 feet above sea level.

On December 21, an examination of the accident site by the NTSB investigator-in-charge, revealed an impact crater about 6 feet in diameter and 3 feet deep. Witness marks from both wings extended from the center of the impact crater. The main wreckage of the airplane was located about 29 feet from the crater, on a magnetic heading of 240 degrees. Both wings exhibited chord-wise crushing through their entire span. The nose of the airplane, from the instrument panel forward, was bent to the right about 90 degrees to the longitudinal axis of the fuselage. The fuselage had rotational twisting and accordion crushing along its longitudinal axis. The aft 3 feet of the fuselage and empennage were relatively undamaged. An evaluation of the flight controls and engine could not be accomplished at the site due to the extensive damage.

The airplane was recovered to a hangar in Anchorage, Alaska, where it was reexamined on January 8, 2003. The inspection of the airplane's engine disclosed no evidence of any preimpact mechanical anomalies.

Tests and research

The VM1000 engine monitor was removed from the airplane, and returned to the manufacturer. Due to damage received during the accident, the memory chips were removed, installed in a new monitor, and a data readout of the last flight was produced. According to the readout, the airplane engine running time since start was 2.2 hours, and the amount of fuel consumed was 17.0 US gallons. The monitor updates and records readings every 3 to 5 seconds. The final readings were: engine fuel pressure 1.0 PSI, which according to the engine manufacturer is sufficient for carburetor operation, and a fuel flow of 7.6 GPH. The manifold pressure was 10.6 in. hg, and the rpm was 1360. The exhaust gas temperature values for the 4 cylinders were between 1200 and 1400 F. The cylinder head temperature values were between 300 and 400 F. The oil pressure was 72 psi, and oil temperature was 191 F. The electrical system voltage was 14.2 VDC.

Pathological information

A postmortem examination of the pilot was conducted under the authority of the Alaska State Medical Examiner, 4500 South Boniface Parkway, Anchorage, Alaska, on December 23, 2002. The examination revealed the pilot's cause of death was "multiple blunt force trauma," and the manner of death was "accident." A forensic toxicology assay was performed by the FAA with negative results.

Additional information

According to the operator, the purpose of the flight was to locate moose with data collecting collars, and relay information between each collar and the University of Alaska, Fairbanks, Alaska. Once a collared moose was located, the airplane became an airborne data transfer point between the collar and the university. A typical flight would require the pilot and observer to locate a collared moose, and then fly in the immediate vicinity of the moose to enable the equipment aboard the airplane to relay data from the moose's collar to the university. The university confirmed that there was no actual data transmission in progress at the time of the accident, however fresh moose foot prints were observed within 50 yards of the accident site.

Due to head trauma, the observer has no independent recollection of the accident flight.

Wreckage release

All airplane wreckage was released to the US Department of the Interior.