The pilot stated that prior to flight, the homebuilt Lightning LS-1 was completely filled with fuel, and he performed a preflight inspection with no anomalies noted.
The airplane departed on Runway 24 at Johnson County Airport (6A4) in Mountain City, Tennessee. Runway 24 is a 4,498-foot-long asphalt runway.
The engine was at full power and the pilot lifted off at 53 knots, but the engine experienced a partial loss of power several seconds later at 70 knots, about midfield.
The pilot was not sure that he could land on the remaining runway and immediately turned the right fuel tank to on and the engine rpm increased significantly.
Within seconds, the engine lost total power and he elected to keep the airplane on the runway heading to clear several obstacles at the end of the runway.
He attempted a forced landing in a field, but had to pull up to clear a fence. The airplane subsequently landed hard in the field and collided with a creek bed, resulting in substantial damage to the forward fuselage. The pilot was seriously injured in the crash.
The pilot told investigators that, in retrospect, he should have rejected the takeoff during the first loss of engine power.
Examination of the wreckage by an FAA inspector revealed substantial damage to the right wing and fuselage. Adequate fuel remained onboard and was drained by first responders due to a potential environmental hazard. The inspector observed that the fuel bowl was about three-fourths full of fuel and the fuel was absent of visible contamination. He checked the air intake, and it was free of obstructions. Additionally, the propeller rotated without any binding.
The wreckage was further examined following its recovery to the airport by the airport manager and a mechanic with an inspection authorization. The electric boost pump switch in the cockpit was noted in the off position. The pilot stated that it was on for takeoff and after impact, he moved the fuel selector, master switch, and fuel pump switch to off.
Disassembly of the engine-driven fuel pump revealed that the diaphragm return spring on the engine side of the diaphragm was corroded. One end of the spring, where it sat against the steel plate on the diaphragm, was rusted completely away leaving an abrupt sharp point.
Examination of the electric boost pump revealed its electrical wire was disconnected from the cockpit pump switch and the pump switch’s spade connector was loose. When the wire was reconnected, the spade connector had to be wiggled to get the pump to activate. Once the pump activated, it pumped 4 psi, which was in the range for normal engine operation.
Additionally, the airplane had experienced one other total loss of engine power a few months prior to the accident. At that time, the pilot was in cruise flight when the engine lost power, however, the propeller kept windmilling and he was able to restore power.
He does not remember everything that he did to restore power, but he remembered switching fuel tanks.
He immediately brought the airplane to the kit manufacturer for troubleshooting, however the cause of the power loss was never determined.
The airplane was assembled from a kit in 2012. Its most recent annual condition inspection was completed on Aug. 16, 2021. At that time, the airframe and engine had accumulated 233 hours since new. The airplane flew an additional 15 hours from the time of the most recent inspection until the accident.
The pilot stated that he was never able to get the fuel pressure sensor connected properly to the Dynon primary flight display (PFD). As such, fuel pressure was not displayed to the pilot. Additionally, fuel pressure data recorded by the Dynon was erroneous.
Data from the PFD were successfully downloaded and plotted. However the fuel pressure parameter was considered unreliable. Many of the recorded values during the accident flight and previous flight ranged from 0.1 to 0.9 psi, which would not support engine operation. The engine manufacturer published a 3.0 psi as nominal for normal engine operation.
Probable Cause: A total loss of engine power due to intermittent operation of both the engine-driven fuel pump and the electric boost pump. Contributing was the pilot’s delay in rejecting the takeoff, after the initial loss of engine power, which resulted in a collision with terrain.
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This April 2022 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.
Should have aborted the takeoff mid-runway? Joseph Addison said it: “He who hesitates is lost.” QED.
/J
I suspect a mechanical fuel pressure gauge would have readily displayed the pump problem.
And it would be apparent the pumps were working at the time of inspection so they would not be dismantled or wiring chased just because.
Perhaps you, like I do, forgot that electronic gauges are always better because, well because, just because.🤔
I always liked the often used excuse for fuel starvation that the totalizer said that there was X amount left, nevermind that the inaccurate gauge showed empty.
So, this 10 YO aircraft was a bit poorly maintained, with corrosion in the mechanical fuel pump and wear preventing it from delivering the needed fuel pressure.
Then, the electrical connection to the boost pump was loose.
So much for the shop that did the last condition inspection..!!
And now a severely damaged aircraft.!
I like my old Cessna; no fuel pump with gravity feed.
I concur with your assessment. Condition inspection is supposed to be equivalent to an annual. All TC aircraft I know get the fuel system checked, pumps checked, etc. Some one needs a checklist of all items to be checked.
Cessna has issued an annual/100hr checklist. It is 4 pages and 83 items.!
I add a few more , like draining the carb bowl of any sediment, drain and clean the gascolator. I go under the panel and check the tightness of all the breaker screws…there are always some that are 1/4 turn loose.!
All this usually takes me 3-4 days, before that A&P IA comes to check and review all the items.