Aviation Accident Summaries

Aviation Accident Summary LAX06CA294

Watsonville, CA, USA

Aircraft #1

N6532L

Grumman American AVN. CORP. AA-5

Analysis

During cruise flight the engine lost power and the airplane impacted several objects in a residential area about 2,000 feet from the airport during an attempted forced landing. The flight was 310 nautical miles. The pilot said that during the preflight he visually checked the fuel levels, which were near the top in both tanks. He calculated his time en route based on a no-wind condition as 2.58 hours, with 38 gallons of fuel and an 8-gallon per hour fuel burn. Prior to departure, he checked weather, which showed that he would encounter 10- to 15-knot headwinds. He reported that two of the flight's legs were longer than he had planned by a total of 35 minutes. He had begun to worry about the airplane's fuel state and had briefly considered a fuel stop short of his destination to refuel. During the descent to his destination airport, the pilot switched the fuel selector to the right fuel tank and the engine lost power. He switched to the left tank, the engine started again, but then lost power. The pilot attempted a forced landing at an uncontrolled airport, but the airplane did not have sufficient altitude to make the runway, and it landed in a residential area short of the airport. A deputy who responded to the accident site noted that there was no smell of fuel around the airplane and the left wing fuel tank was empty. The right wing had separated during the accident sequence. The pilot stated that there were no mechanical anomalies encountered with the airplane or engine.

Factual Information

On September 15, 2006, about 2115 Pacific daylight time, a Grumman American AVN. Corp. AA-5, N6532L, lost engine power and collided with objects on a residential street while attempting to make a forced landing at Watsonville Municipal Airport (WVI), Watsonville, California. The commercial pilot operated the rental airplane under the provisions of 14 CFR Part 91 as a personal cross-country flight. The airplane was destroyed. The pilot, the sole occupant, was not injured, and there were no ground injuries. Night visual meteorological conditions prevailed for the flight that departed Fullerton Municipal Airport (FUL), Fullerton, California, about 1730. No flight plan had been filed. The flight was destined for the Norman Y. Mineta San Jose International Airport (SJC), San Jose, California. In the pilot's written statement to the National Transportation Safety Board, he reported that he had planned a visual flight rules (VFR) flight from FUL to SJC via Los Angeles special flight rules area, Santa Monica VOR (Very high frequency Omnidirectional Range), TWINE intersection, Fillmore VOR, San Marcus VOR, Paso Robles VOR, Salinas VOR, to SJC. The total distance was calculated as 310 nautical miles with a computed time of 2.58 hours with no wind, at an altitude of 8,500 feet mean sea level (msl). The pilot received a weather brief via DUATS (Direct User Access Terminal Service), which showed a headwind in the range of 10 to 15 knots or more depending on the altitude. He based the en route calculations on 38 gallons of fuel with a fuel burn of 8-gallons per hour at a low power setting and lean mixture. He estimated that he had enough fuel for 5 hours of flight. During the airplane preflight, he visually checked the fuel levels to be near the top of the tank, and the fuel gauges provided a full indication. There was not an exhaust gas temperature (EGT) gauge on the airplane so the pilot leaned the mixture by reducing the mixture arm until the engine began to run rough and then he advanced the arm until the engine ran smooth. The pilot reported that after departing the Los Angeles area he had to descend and then climb back to his original altitude of 8,500 feet due to turbulence. While in cruise he noted that the last two legs of his flight prior to landing at his destination airport had taken longer than he had projected. He also reported that two of the flights' legs were longer than he had planned by a total of 35 minutes. One leg was 15 minutes longer, and the other leg was 20 minutes longer than planned. The pilot stated again that all of his calculations were done without considering the winds. At one point during the flight he noted that the GPS (global positioning system) reported the airplane's groundspeed as 80 knots. The pilot stated that after departing the Salinas VOR he started to worry about the remaining fuel, and was thinking about landing at a closer airport to refuel. He had been watching the fuel gauges very closely and switched tanks every half an hour. As the flight neared SJC, the air traffic controller instructed the pilot to descend to 6,500 feet in preparation for landing. He noted that the fuel gauge needles were pointing to the top of the red arc and he assumed that there was 1/8 to 1/4 of fuel remaining in each fuel tank. He reported that the fuel selector was selected to the right fuel tank when the engine lost power for the first time. He positioned the selector to the left fuel tank and the engine restarted. The pilot informed the controller that he had a low fuel state and needed to land at the nearest airport. The controller told him that WVI was at the pilot's 12 o'clock and 10 miles from his current location. A few minutes later, the engine lost power. The pilot radioed the controller that he had an engine failure, and he had the airport's beacon insight and was proceeding towards the airport. The controller informed the pilot that WVI had pilot controlled lighting, but the pilot was unable to illuminate the runway lights. He set up for best glide, 80 knots, and continued to switch the fuel selector back and forth between the left and right tanks. Each time the engine would run a little bit and then "quit." He switched radio frequencies back to the air traffic controller and asked for vectors to the airport as he was not able to activate the pilot controlled lighting. The pilot knew his altitude was too low and that he was not going to make it to the airport. As the airplane descended into a residential area, he knew that he would have to land on the street. During the landing, the right wing struck a light pole and a small tree, and separated from the fuselage. The airplane also struck and severed a natural gas line on the side of a house, as well as scraping the side of the house. After the airplane came to a stop, the pilot was able to exit the airplane on his own. After the accident, the pilot noted that his flight was 3.8 hours, and that he should have stopped to refuel after 3 hours of flight, which would have given him the opportunity to recalculate the airplane's fuel burn. He also indicated that the airplane was fueled with 2.6 gallons of fuel earlier in the day and had been flown for 0.4 hours before his flight. The pilot reported no mechanical anomalies with the airplane. A responding deputy from the Santa Clara County Sheriff's Department reported that the airplane came to rest about 2,000 feet from the Watsonville Airport. The right wing had separated from the airplane. There was no smell of fuel surrounding the airplane, and the left wing fuel tank was "dry."

Probable Cause and Findings

A loss of engine power due to fuel exhaustion as a result of the pilot's inadequate preflight planning, en route fuel consumption calculations, and in-flight decision to continue to the destination instead of stopping en route for fuel.

 

Source: NTSB Aviation Accident Database

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