Aviation Accident Summaries

Aviation Accident Summary ANC02LA058

South Naknek, AK, USA

Aircraft #1

N3025X

Cessna 150

Analysis

The pilot reported that he had been on a cross country flight for about 3.5 hours when the airplane's engine lost power. He said he restarted the engine, and initiated a climb to gain altitude. With the destination airport in sight, the airplane's engine again lost power, and would not restart. The pilot decided the airplane would not make it to the airport, and he banked the airplane steeply to align it with a road perpendicular to the route of flight. About 20 feet above the road, the airplane "fell out" and impacted the roadway. The airplane bounced off of the roadway, and impacted the terrain inverted. The pilot said he had a favorable tailwind during the flight, and therefore, he did not make a planned intermediate fuel stop. He said he planned the flight using a straight fuel burn of 5.5 gallons per hour, and had 26 gallons of fuel in the airplane's tanks for the flight. The Cessna owner's manual states that 22.5 gallons of the airplane's 26 gallon fuel capacity are usable, and that at 71% cruise power, the engine burns 5.3 gallons per hour, but at higher power settings the engine may burn as much as 7.2 gallons per hour. The pilot did not factor in a variable fuel burn rate for engine start, taxi, run-up, takeoff, and climb. The engine was mounted postaccident on a test stand, and ran at full rated rpm.

Factual Information

On June 23, 2002, about 1630 Alaska daylight time, a Cessna 150 airplane, N3025X, sustained substantial damage when it encountered rough terrain during an emergency landing after a loss of engine power, about one mile northeast of the South Naknek Airport, South Naknek, Alaska. The airplane was being operated as a visual flight rules (VFR) personal flight under Title 14, CFR Part 91, when the accident occurred. The private pilot received minor injuries and the passenger sustained serious injuries. Visual meteorological conditions prevailed, and a VFR flight plan was filed. The flight originated at Merrill Field, Anchorage, Alaska, about 1300. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on June 24, the pilot said he departed Merrill Field as a flight of two with a friend flying a Piper PA-18. He said they planned an en route fuel stop at Nondalton, Alaska, but they had a good tailwind, and calculated they could make it to their destination without the fuel stop. The two airplanes separated at Naknek, and the accident airplane continued to South Naknek. The pilot said he could see the airport at South Naknek when the airplane's engine started to surge and cut out. He decided the airplane wasn't going to make it to the airport, and made a steep right turn to line up with a road perpendicular to his route of flight. He said during the turn the engine quit completely, and about 20 feet above the road, the airplane "fell out," and bounced hard on the roadway. He said the airplane exited the roadway to the left, encountered a ditch, trees and brush, and came to rest upside down. He said the next thing he remembered was he and the passenger sitting on the wing waiting for help to arrive. In his written statement to the NTSB, the pilot reported that upon arrival in the South Naknek area he did not fly directly to the airport. He reported that he flew along the river looking for his skiff. He reported that the first time the engine quit he restarted it, initiated a climb to gain altitude, and headed for the airport. Varying slightly from his original, verbal statement to the IIC, he wrote that the engine quit completely prior to the turn which aligned the airplane with the road where he intended to land. According to the pilot, in addition to himself and the passenger, the airplane was carrying personal gear for two, camping equipment, and 15 gallons of fuel for the airplane in the cargo area behind the seats. A witness at Merrill Field on the morning of June 23, 2002, said he saw the accident airplane depart. He said the airplane rolled almost the entire length of runway 06 before becoming airborne, and the airplane climbed very slowly. Runway 06 is 4,000 feet long. The airplane sustained damage to both wings, the fuselage, and empennage. During his conversation with the IIC, the pilot said he had 26 gallons of fuel in the airplane's tanks, and flight planned the airplane for a straight fuel burn of 5.5 gallons per hour, without giving consideration to the varying fuel burn rates for starting, taxi, run-up, takeoff, and climb. In his written report to the NTSB, the pilot indicated the 321-statute-mile cross country flight was about 3.5 hours long, and estimated a total fuel burn of about 19.25 gallons. The Cessna owner's manual indicates that 22.5 gallons of the airplane's 26 gallon fuel capacity are usable, and that the engine will burn 5.3 gallons per hour at 71% power, 6.0 gallons per hour at 79% power, and depending upon the power setting, may consume as much as 7.2 gallons of fuel per hour. According to the owner's manual, these figures are at cruise, and do not allow for taxi, run up, takeoff, or time to climb. On August 9, 2002, about 1028, in the presence of the IIC, the engine, serial number 5769-8-A-R, was removed from the accident airplane, and mounted on an engine test stand at Alaska Aircraft Engines, Inc. located at Merrill Field. A hole in the engine oil reservoir, which was a result of impact damage due to the accident, was patched. The engine was serviced with oil and a propeller attached. The engine was started, and produced full rated rpm.

Probable Cause and Findings

The pilot's failure to refuel the airplane resulting in fuel exhaustion in cruise flight, and his inadvertently stalling the airplane during the ensuing emergency landing.

 

Source: NTSB Aviation Accident Database

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