19 Sep 20206:38 reconstruction4K views

Both Engines Lost Power as a B-25 Tried to Reach Stockton

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Timeline
1
19 September 2020 — The B-25N was in cruise near Stockton with the copilot flying.
2
Cruise — Left-engine fuel pressure fluctuated and a brief power loss occurred.
3
Approaching Stockton — Both fuel-pressure indications fluctuated; the pilot suspected fuel starvation.
4
Off-airport decision — The pilot selected a field because residential areas lay between the aircraft and the airport.
5
Field landing — Both engines lost total power; the aircraft struck two ditches during the landing sequence.
6
After the crash — The copilot and passenger were seriously injured and the pilot sustained minor injuries.
7
Investigation — Fuel exhaustion was identified as the cause, with gauge indications and inadequate fuel planning/inspection contributing.

The first engine warning came as fluctuating fuel pressure

On 19 September 2020, North American B-25N N7946C was in cruise near Stockton, California, when the left engine's fuel pressure fluctuated and the engine briefly lost power. The aircraft was being flown by the copilot while the pilot monitored the situation from the right seat. The pilot became concerned that the engine-driven fuel pump might have failed, selected the electric boost pumps to high and had the passenger, who was also the aircraft's mechanic, open the fuel cross-feed valve.

The problem spread to both engines

As the aircraft neared Stockton Metropolitan Airport, both fuel-pressure indications began fluctuating. The pilot interpreted the indications as possible fuel starvation. Because residential areas lay between the aircraft and the airport, he chose an off-airport landing site in a field. The pilot took control and turned toward the field. Soon afterward, both engines lost total power.

The field landing became an impact sequence

During the landing roll, the pilot saw a ditch and managed to lift the aircraft briefly to avoid it. A second, larger ditch could not be avoided. The aircraft struck it, became airborne again and then impacted the ground, substantially damaging the fuselage. The copilot and passenger sustained serious injuries; the pilot sustained minor injuries.

Fuel evidence was decisive

Recovery personnel found only about one gallon of fuel in the aircraft's main tanks. Investigators also found that the fuel gauges displayed incorrect readings after the tanks were filled with water during examination. The aircraft had been refueled the previous day, but the investigation could not establish exactly how much fuel remained at the accident time. Recorded flight activity and the pilot's fuel-burn assumption did not align with the amount of fuel that should have been consumed.

The planning problem

The investigation concluded that fuel exhaustion caused the total loss of engine power. Contributing issues included erroneous fuel-gauge indications and inadequate preflight planning and inspection. The case therefore involved both a technical warning system problem and a human planning problem. The investigation did not need to assume a hidden engine defect: the available fuel evidence was sufficient to explain the dual power loss.

The fuel evidence in this accident was more complicated than simply asking whether the airplane had been refueled. The aircraft had been refueled the day before, but investigators could not determine precisely how much fuel remained at the accident time. The stated fuel capacity was substantially larger than the amount reportedly added, and the pilot's assumed burn rate did not match the consumption suggested by the recorded flight activity. ADS-B data showed that the aircraft had accumulated about four hours and one minute of flight since refueling, including multiple takeoffs and landings. The occupants also did not visually verify fuel quantity in all four main tanks before the accident flight. Investigators linked the empty tanks, erroneous fuel-gauge indications and inadequate planning to the fuel exhaustion rather than identifying a hidden engine defect.

Accident Facts

Details
North American B-25N N7946C | 19 September 2020 | Stockton, California

Sources

Audio from the original air traffic control recording, sourced from public recordings and released investigation records. The reconstruction, animation and written account are our own.
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