The commercial pilot stated that he had experienced engine roughness during previous flights in the Kitfox 7.
Maintenance personnel determined that the airplane was not receiving adequate fuel at full power, even with both electric fuel pumps operating. As a result, they installed check valves in the fuel system and replaced the fuel pressure regulator.
On the day of the accident, the engine experienced a total loss of power after both fuel pumps were turned off during a pre-takeoff engine run-up.
The pilot and mechanic then performed another run-up check, during which the engine operated normally.
The pilot subsequently departed and entered the traffic pattern at the airport in Cody, Wyoming. While on the downwind leg, with both fuel pumps operating, he reduced engine power and the engine experienced a total loss of power.
He performed a forced landing to a field, during which the nose landing gear collapsed.
Post-accident examination of the engine revealed that the fuel pressure and airbox pressure differential was not within the engine manufacturer’s limits. The fuel pressure regulator was adjusted within those limits, and the engine was subsequently test run with no anomalies.
Probable cause: Improper maintenance of the fuel pressure regulator, which resulted in an excessive fuel and airbox pressure differential and subsequent loss of engine power.
NTSB Identification: CEN17LA065
This December 2016 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
Robert Hartmaier says
I agree with all of your comments and also wonder why he could not make the runway if he was on downwind!
Sarah A says
If it does not work perfectly on the ground then it is not likely to do any better in the air. That plane was screaming that there was a problem with fuel delivery and the best solution they seemed to have was throwing parts at it. Some of this can be attributed to a mechanic who was schooled on Lycoming and Continental engines having to work on an engine type he was not familiar with and might not have spent much time with the maintenance manual. Maybe he was going by experience with those other engine types when he started jacking up the fuel pressure which apparently was the source of the problem. Such problems will probably continue until Rotax engines become part of A&P school and those new mechanics get out into the world. to apply that knowledge
Just as a comment that fuel system sounds like a bad one especially the choice of materials. The full narrative mentioned several instances where transparent green fuel lines were used as well as unidentified black fuel lines. To me that sounds like a fuel system put together with materials from the local auto parts store and that is not the professional way to do it. While it passed its inspection from the FAA that is no guarantee that the all of the builders choices were good ones.