The pilot reported the Cessna 150 had seven gallons of fuel and that he had planned a short flight to a nearby airport to purchase more fuel.
During initial climb, about 750′ above ground level, the engine experienced a partial loss of power.
The pilot applied carburetor heat, but the engine rpm remained at about 1,700, and he was unable to maintain the airplane’s altitude.
He turned the airplane back toward the airport in Gettysburg, Pennsylvania, and realized it was not going to reach the runway.
He subsequently attempted to land in a field ahead of the runway, but the plane hit trees in the field.
The airplane’s left wing fuel tank cap was found on the runway; it likely became separated during the takeoff roll. About two gallons of fuel was drained from each wing fuel tank after the accident, and more fuel may have leaked out after the accident due to the airplane’s position, therefore, it is unlikely that fuel leaked out during the brief flight.
The engine was subsequently successfully test run on the airframe. Review of a carburetor icing chart revealed that the atmospheric conditions at the time of the accident were outside of the icing envelope. The reason for the loss of engine power could not be determined.
Probable cause: A partial loss of engine power during initial climb for undetermined reasons because examination of the engine and a successful test-run did not reveal any anomalies that would preclude normal operation.
NTSB Identification: ERA16LA116
This February 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.
Cap falling off (perhaps contributed) but starting a flight with minimal fuel is a real problem (nothing new here). It sounds like this pilot did not plan for the unlikely, but possible event that he was not going to be able to land at his intended destination – runways get shut down unexpectedly, etc. That’s my only real critique. Hate to see a good plane get bent. 🙁
The impossible turn was a factor in the crash.
G Marks says
No it wasn’t, he made the turn back towards the airport just fine.
It’s 2018 and airplanes still will not fly without fuel of some sort…. Air is not an acceptable fuel however…
Wylbur Wrong says
Absolutely correct. However, reading just the NTSB report, the pilot did have fuel.
“The inspector also noted that the airplane’s left fuel tank cap remained on the runway; however, recovery personnel drained approximately 2 gallons from each fuel tank. The recovery personnel did not observe contamination in the fuel. Additionally, they reported that more fuel may have leaked from the airplane through the vents or left fuel tank opening, as the airplane was suspended nose-down, slightly beyond the vertical position.”
To determine how much of a problem a missing fuel cap is, is rather an expensive undertaking involving a wind tunnel, or creating something close to that.
Why would you do this? To prove under a controlled environment if the following is actually the case:
[Theory] A fuel cap not having been attached correctly and ultimately falling off would allow for the fuel system to be “under pressurized”. Think of it like this, a C150 depends on gravity to feed the fuel system to the fuel pump. The fuel pump on a C150 does not produce a lot of vacuum (as I understand it, but produces good pressure), therefore, with the wind going across the top of the tank’s fill hole that airflow will generate a “vacuum” and un-pressure the system causing the fuel to not flow correctly from the wing down to the engine’s fuel pump.
Given this was the left fuel cap, it would cause a similar effect of a block in the cross-over vent tube (to the right tank).
When that cross-over is blocked, fuel does not flow from the right tank, but flows mostly from the left tank (C150’s fuel selection is OFF or BOTH) which effectively develops a vacuum in that tank so fuel will not flow out of it.
Therefore, with the left fuel cap missing, the airflow past the filler hole would cause reduced air pressure in that left tank, and evacuating air from the right tank as well. And so the engine would not be able to produce full power because the fuel will not flow properly (gravity feed) down to the engine’s fuel pump.
The cause of this crash, in my opinion was the failure to correctly replace the left fuel cap after checking the fuel tank contents.
Cessna’s are well know to siphon fuel out of a tank if the cap is missing. A full tank will be drained quickly.!
This ‘old’ engine probably burns more fuel than per the POH, and with 1.75 gallons unuseabe and only 2 gallons found in each tank….he was essentially out of fuel.
Note that all carbureted Cessnas are gravity flow..no fuel pump. The system operates on about 1 psi fuel pressure head.
So, a botched pre-flight and more Stupid Pilot Tricks.!
Glenn Swiatek says
Yeah, 2018 and I haven’t read a new way a pilot can mess up in quite awhile. Rinse lather repeat … but only on the exterior of the scalp.
In this case the aircraft was not “out of fuel”. Based on the very high risk of carb ice and absence of mechanical problems the most likely root cause of partial power was the engine not getting air. Too bad the pilot didn’t apply carb heat sooner. But, the POH recommends full power and no carb heat for climbs, and a lot of pilots (me included) were taught that was all we needed to do to prevent ice from clogging the carb venturi. The missing or loose fuel cap might have contributed to a later fuel exhaustion accident had the flight continued for another half hour or longer. However, in this case the NTSB said it was not the ‘smoking gun’ assumed by other commenters.