Casualties unknown

1998-11-19: Mooney M20F (N3500X) — Upland, CA

Upland, CA, US

On November 19, 1998, a Mooney M20F (registration N3500X) was involved in an aviation accident near Upland, CA. Investigators recorded the probable cause as: Loss of engine power due to water contaminated fuel and the pilot's inadequate preflight inspection of the airplane. A factor was the failure of the owner/pilot to properly maintain the airplane. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

During initial climb the engine sputtered; after leveling it ran smoothly until it quit on downwind. Post-accident inspection found water in fuel tanks and system, deteriorated fuel cap O-rings, and rusted filler ports.

Accident Overview

The aircraft experienced engine sputtering during the initial climb after takeoff. The pilot leveled the airplane, and the engine subsequently operated smoothly. However, while on a downwind leg, the engine quit. Prior to takeoff, during the engine run-up, the engine had sputtered and quit.

Witness Observations

According to witnesses, rain had fallen during the two weeks prior to the accident, and the airplane had been parked outside in transient parking. One witness reported that an inspection of the O-ring seals on the fuel caps had revealed evidence of deterioration. Witnesses further stated that the aircraft had not been refueled on the day of the accident.

Post-Accident Examination

After the accident, recovery personnel removed 1.5 cups of water from the left wing and 2 tablespoons of water from the right wing. Each wing contained 17 gallons of fuel. Examination of the fuel system found deteriorated O-ring seals on the fuel caps and rusted filler ports on the wings. A liquid substance removed from the fuel injection servo and the engine-driven fuel pump fuel line tested positive for water when tested with water finding paste. The fuel flow divider was disassembled and showed no evidence of damage; however, water was noted on the fuel side of the diaphragm. No further discrepancies were noted with the engine.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001211X11462. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.