Aero Commander 100-180 N3733X accident near Deport, Texas

Probable cause

A total loss of engine power due to water contamination of the fuel system. Contributing to the accident was the pilot/owner's inadequate maintenance of the fuel caps.

NTSB analysis

The private pilot reported that the airplane had been parked outside and exposed to an extended period of rainfall in the days leading to the accident. On the day before the accident, the pilot drained nearly 2 gallons of water from the fuel system before he saw clean, blue fuel. He subsequently repositioned the airplane on the ramp to see if he could get more water out of the tanks and installed new gaskets for the fuel caps. On the day of the accident, the pilot sumped the fuel system and found a small amount of water during the first check but reported that it was clear on the second check. During the pre-takeoff engine run-up, the airplane operated normally, and the pilot chose to depart.

About 25 minutes after takeoff, the pilot executed a steep turn about 500 ft above ground level. About 1 minute after leveling off, the engine sputtered once and experienced a total loss of power. His attempt to restart the engine was unsuccessful. The pilot performed a forced landing to a field but was unable to stop the airplane before hitting trees during the landing roll. He reported that there were no mechanical malfunctions or failures with the airplane that would have precluded normal operation before the loss of engine power. Postaccident examination of the airplane revealed that the right wing was separated from the airframe and contained no fuel. The left wing was about 1/2 full, but the fuel was not sampled. The fuel filler neck and cap showed large amounts of rust, indicative of inadequate maintenance of the fuel caps, which would have allowed water to enter the neck and tanks. It is likely that precipitation entered the fuel system around the poorly-maintained fuel filler and cap, which resulted in water contamination of the fuel, and that there was water remaining in the system even after the pilot drained large amounts of water before the flight, which resulted in the subsequent loss of engine power.

Text from the NTSB. Open the NTSB docket for CEN18LA113 for the full record.