The pilot, who was making a personal cross-country flight, said the Cessna 210’s engine began running roughly during cruise flight. He leaned the mixture, and the engine roughness subsided. However, a few minutes later, the engine began running roughly again.
He switched fuel tanks, but the engine continued running roughly. Shortly after, the engine lost all power.
The pilot made a forced landing in a soft, sandy field near Desdemona, Texas, and the airplane nosed over.
A post-accident engine test run revealed that the engine would not maintain power and that the fuel flow was excessive. A subsequent bench test of the fuel pump revealed that the pump was set to a high fuel flow setting, beyond the engine’s normal limits.
The fuel pump was adjusted and reinstalled on the engine for another test run. During the second test run, the engine operated smoothly at a stabilized fuel flow within the operating limits for the engine.
Given this evidence, it is likely that the engine lost power due the fuel pump’s flow setting being set to high, which resulted in an excessive fuel flow to the engine.
Probable cause: The total loss of engine power due to the fuel pump’s fuel flow setting being set too high, which resulted in an excessive fuel flow to the engine.
NTSB Identification: CEN18LA229
This June 2018 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.
Glenn:
Call it what you like. Unless you or I can crack the cowl, open the engine, and examine ALL of the work from a basis of our own knowledge we must TRUST the work of others. We also rely upon the honesty and integrity of every individual, business, and government agency that participates in the industry. TRUST and integrity is the foundation of every bit of design, work on any part of the aircraft that we do not do ourselves (assuming we have that skill and knowledge), adherence to fuel specifications, ATC performance, etc. etc. etc. Aviation, as with every other complex system in our technology intensive lives relies on TRUST and the integrity others.
Further proof that aviation runs on TRUST even more than gobs of money. In this case a failure of TRUST occurred when the last IA/AMT adjusted the fuel flow.
From the NTSB Accident Docket’s engine examination report:
“The engine was placed in the test cell and started. The engine was run at 1,200 rpm and 1,600 rpm
with the fuel pump mixture control at full. After 2 minutes of run time, the engine power started
oscillating. The engine was shut down and the mixture control was adjusted to about half of where
it was originally set. The engine was started again and after 1 minute and 20 seconds the engine
power once again began to decrease, with the fuel pressure reaching 8 psi higher than the max
unmetered flow limit of 32 psi.
“The Romec fuel pump, part number 630751-3, serial number C3010, was removed and placed on
a flow bench. At full power, 2,700 rpm, the fuel flow was about 170 pph with a fuel pressure of
92 psi. The fuel pressure should have been between 29 and 32 psi. The adjustment screw was
adjusted and the fuel pressure dropped to 30 psi. The pump was reinstalled on the engine.
The engine was restarted and fun up to 1,600 rpm. The rpm slowly dropped to 1,498 rpm. The
engine power was increased to 2,552 rpm and the fuel pressure stabilized at 30.18 psi.
“During the engine runs it was observed that the engine was overboosting. During the second
engine run the turbocharger controller was adjusted to stop the overboosting from occurring.
“Pam Sullivan
Air Safety Investigator
National Transportation Safety Board
Central Region, Denver, CO”
Trust ? Or Competence ?