Primary finding
Probable cause
The total loss of engine power due to fuel starvation as a result of a deteriorated gascolator gasket. Contributing was the failure of the mechanic to replace the gasket during the most recent condition inspection.
Investigator assessment
Analysis narrative
Shortly after takeoff, as the airplane was climbing through 300 ft above ground level, the engine misfired, then suddenly stopped producing power. Unable to troubleshoot due to the low altitude, the pilot lowered the nose and attempted a forced landing on the remaining runway. The airplane landed hard, collapsing the landing gear and damaging the wings and airframe. Postaccident examination of the airplane did not reveal any engine anomalies; however, an examination of the fuel system revealed the fuel gascolator was installed partially outside of the engine compartment, exposing it to the air slipstream. The gascolator exhibited features consistent with a fuel leak. The gascolator bowl was not completely secure to the upper portion of the gascolator and it leaked fuel when touched by hand. The most recent engine maintenance was completed about 10 days before the accident and, although the fuel gascolator gasket was not mentioned in the logbook entry, a fuel system inspection was documented. The condition of the gasket would have warranted replacement. The gascolator bowl gasket was stiff and cracked, which likely allowed fuel to leak out during the flight, starving the engine of fuel. The circumstances of the accident are consistent with a total loss of engine power due to fuel starvation, which resulted in a loss of engine power and hard landing.
Source record
Factual narrative
On October 17, 2024, at 1515 eastern daylight time, an experimental amateur-built Zenith Zodiac 601HDS airplane, N511JG, was substantially damaged when it was involved in an accident near Altoona, Pennsylvania. The private pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The private pilot reported that there were no irregularities noted with the airplane during the preflight inspection, engine run-up, or taxi before departing from runway 3 at Altoona/Blair County Airport (AOO), Altoona, Pennsylvania. The pilot intended to remain in the airport traffic pattern; however, during the initial climb, when the airplane was climbing through 300 ft above ground level, the engine started to “misfire,” then immediately stopped producing power. Unable to troubleshoot due to the low altitude, the pilot lowered the nose and attempted a forced landing on the remaining runway. The airplane landed hard and the landing gear collapsed, which resulted in the wings and airframe buckling. The airplane then skidded to a stop on the side of the runway. Examination of the airplane revealed signatures to the propeller that were consistent with a lack of rotation during the impact; the engine was intact. Engine crankshaft and valvetrain continuity was established and compression was attained on each cylinder. Both magnetos produced spark at each of the posts. A subsequent examination of the fuel system revealed 10 gallons of fuel on board. In addition, the fuel gascolator was installed partially outside of the engine compartment, exposing it to the air slipstream. The gascolator exhibited features consistent with a fuel leak. The gascolator bowl was not completely secure to the upper portion of the gascolator and it would leak fuel when lightly touched by hand. The gascolator was opened and the gasket at the top of the bowl was found to be stiff and cracked. A review of maintenance records documented an annual condition inspection had been completed about 10 days before the accident. The logbook entry did not document any maintenance or inspection to the gascolator specifically, but the fuel system inspection was documented and tested, yielding no leaks.