No fatalities

2013-09-19: Beechcraft 90 King Air (N191TP) — We Fly — Idaho Falls, United States of America

Idaho Falls, United States of AmericaLanding (descent or approach)

On September 19, 2013, a Beechcraft 90 King Air (registration N191TP) operated by We Fly was involved in an aviation accident near Idaho Falls, United States of America during landing or approach. No fatalities were reported. Investigators recorded the probable cause as: The pilot's inadequate preflight fuel planning, which resulted in departure with insufficient fuel to complete the flight, and consequent inflight power loss due to fuel exhaustion. This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A).

Sourcesthe Bureau of Aircraft Accidents Archives (B3A)Primary reportUpdated 1781193977Data APIEditorial standards

A pilot's failure to verify fuel quantities and inadequate preflight planning led to fuel exhaustion on final approach. All four tanks were empty postaccident, with no mechanical anomalies found.

Accident Overview

During a return flight to the home airport, both engines lost power while the airplane was on final approach. The pilot executed a forced landing to a field approximately 1.2 miles short of the runway. Postaccident examination revealed that all four fuel tanks were devoid of fuel. No preimpact mechanical anomalies, including fuel leaks, were found that would have precluded continued flight.

Fuel Management

The airplane was equipped with two main fuel tanks (132 usable gallons each) and two nacelle fuel tanks (60 usable gallons each). In normal operation, fuel from each nacelle tank is supplied to its respective engine, and fuel is automatically transferred from each main tank to its respective nacelle tank.

At the home airport before departure, the pilot noted that the cockpit fuel quantity gauges indicated the nacelle tanks were full. He believed the main tanks had sufficient fuel for 30 minutes of flight but did not verify the actual fuel quantity by any other means. Thirty gallons of fuel were added to each main tank; they were not topped off.

The airplane, with two passengers, flew to an interim stop about 45 miles away, where a third passenger boarded. The flight continued to the destination, another 165 miles away. At the destination, the pilot observed that the nacelle tanks still indicated full and surmised the main tanks were not empty, but did not note the actual quantity. Forty gallons were added to each main tank, again without topping off or verifying by other means.

The return flight to the interim stop was uneventful. The third passenger deplaned, and the airplane departed for the home airport. The pilot later reported that at the time of power loss, the fuel gauges indicated fuel remained.

Postaccident Examination and Calculations

The airplane manufacturer performed fuel-consumption calculations for the two city pairs. Because the pilot did not provide flight routes, altitudes, speeds, or times, the calculations assumed direct routing in zero-wind conditions, nominal performance, and assumed cruise altitudes and speeds. The results indicated the round trip would have burned less fuel than the total available derived from pilot-provided information, but the lack of actual flight parameters limited the utility of the comparison.

The manufacturer calculated that the accident flight leg (interim airport to home airport) would have consumed about 28.5 gallons total. The airplane was devoid of fuel at the accident site, suggesting the pilot departed the interim airport with significantly less than the manufacturer's minimum allowable departure fuel quantity of about 39.5 gallons per side.

The absence of preimpact mechanical problems and the lack of objective fuel quantity information indicate that the fuel exhaustion resulted from the pilot's inadequate and improper pre- and inflight fuel planning and procedures.

Probable cause

The pilot's inadequate preflight fuel planning, which resulted in departure with insufficient fuel to complete the flight, and consequent inflight power loss due to fuel exhaustion.