Piper PA 24-250 N6570P and Cessna 172N N737CL accident near San Jose, California

Probable cause

The pilot’s failure to sump the fuel tanks, which resulted in water contamination, a partial loss of engine power during takeoff, and collision with a taxiing airplane during the subsequent forced landing.

The other pilot’s failure to sump the fuel tanks, which resulted in water contamination, a partial loss of engine power during takeoff, and collision with the taxiing airplane during the subsequent forced landing.

NTSB analysis

This was the first flight for the Piper airplane in the last 3 months, during which time, it was parked on a ramp outside in the winter. The pilot reported that he performed a preflight inspection but that he did not sump the fuel system. The airplane's main fuel tanks were full with fuel, and the fuel selector valves were set to the main fuel tanks. Shortly after takeoff at an altitude of about 300 to 400 feet above ground level, the engine began to "sputter" with a corresponding partial loss of power. The pilot cycled the throttle control with no change in engine power and then turned back toward the airport. The airplane did not have sufficient altitude to reach a runway, so the pilot performed a gear-up landing onto a taxiway. After landing, the airplane slid across the taxiway surface and struck a taxiing Cessna airplane; both airplanes sustained substantial damage.

Postaccident examination of the engine did not reveal any anomalies that would have precluded normal operation, and it started and ran smoothly during a subsequent test run. Given the pilot's failure to sump the fuel system and the fact that the engine did not experience a total loss of engine power, it is likely that the fuel system became contaminated with water while the airplane sat on the ramp for the preceding 3 months.

The Cessna airplane was taxiing when a Piper airplane collided with it. This was the first flight for the Piper airplane in the last 3 months, during which time, it was parked on a ramp outside in the winter. The pilot reported that he performed a preflight inspection but that he did not sump the fuel system. The airplane's main fuel tanks were full with fuel, and the fuel selector valves were set to the main fuel tanks. Shortly after takeoff at an altitude of about 300 to 400 feet above ground level, the engine began to "sputter" with a corresponding partial loss of power. The pilot cycled the throttle control with no change in engine power and then turned back toward the airport. The airplane did not have sufficient altitude to reach a runway, so the pilot performed a gear-up landing onto a taxiway. After landing, the airplane slid across the taxiway surface and struck the taxiing Cessna airplane; both airplanes sustained substantial damage.

Postaccident examination of the engine did not reveal any anomalies that would have precluded normal operation, and it started and ran smoothly during a subsequent test run. Given the pilot's failure to sump the fuel system and the fact that the engine did not experience a total loss of engine power, it is likely that the fuel system became contaminated with water while the airplane sat on the ramp for the preceding 3 months.

Text from the NTSB. Open the NTSB docket for WPR14LA099 for the full record.