On December 11, 1990, a Maule M-4-220C (registration N40614) operated by Matrinek, Dennis P was involved in an aviation accident near Romeoville, IL. Investigators recorded the probable cause as: THE PILOT'S INADEQUATE PREFLIGHT INSPECTION RESULTING IN POWER LOSS FROM FUEL CONTAMINATION. A FACTOR IN THE ACCIDENT WAS THE OWNER'S FAILURE TO ACCOMPLISH AIRWORTHINESS DIRECTIVE 84-9-7 WHICH PROVIDED DIRECT, CONVENIENT ACCESS TO SAMPLE AND PURGE THE MAIN… This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot drained water from fuel drains but experienced engine roughness during runup. After smoothing out, the engine lost power during climb and turn. Investigation revealed water contamination throughout the fuel system and non-compliance with an airworthiness directive regarding drain valves.
Event Description
A pilot reported that before a flight, he drained eight vials of water from the low-point fuel drains located on the fuselage. The fuel eventually ran clear. During the subsequent engine runup, the engine exhibited roughness. The pilot continued the runup until the engine ran smoothly. Shortly after takeoff, during climbout and a sustained turn, the engine lost power.
Fuel System Examination
Post-incident examination of the fuel system revealed water contamination throughout. The contamination was present in all parts of the fuel system that were inspected.
Maintenance Compliance
The airplane had not been retrofitted with quick drain valves in place of the original 1/8-inch NPT sump plugs on the left and right main fuel tanks. This retrofit was mandated by Airworthiness Directive 84-9-7. The pilot, who is also the airplane owner and holds an Airframe-and-Powerplant mechanic certificate, performed the fuel draining procedure.