What happened
The aircraft was descending through an altitude of 31,600 feet when the master caution light illuminated alongside the right inlet fuel pressure low warning. The crew identified that the circuit breaker for the fuel quantity transfer system had tripped. Upon resetting this breaker, all fuel quantity gauges dropped to zero, indicating a complete loss of fuel data. An emergency was declared with Albuquerque ARTC Center, and the flight was vectored toward Luke Air Force Base.
At 24,000 feet, the right engine flamed out due to lack of fuel supply. The crew managed to restart the engine at 10,000 feet. The aircraft landed safely at Luke AFB with both engines operating normally. After shutdown, the auxiliary power unit (APU) continued to run for approximately 20 minutes before ceasing operation due to fuel exhaustion. Only 4-5 gallons of fuel remained in the tanks.
The flight had departed Phoenix on May 27 bound for Fresno with 15,000 pounds of fuel onboard. No additional fuel was added at Fresno because the gauges still indicated 15,000 pounds despite the electrical fault. The Cessna 600 (or similar type if identifiable, but source implies generic acft) suffered from a misleading indication system.
The investigation
Investigators examined the aircraft's fuel quantity indicating system after the event. They found that with the fuel quantity transfer circuit breaker open, the gauges remained frozen at their last known position when power was lost. However, the press-to-test function on the instrument panel failed to operate correctly under these conditions. No mechanical malfunction of the fuel quantity indicating system itself was detected.
Findings
The primary issue was the tripped circuit breaker for the fuel quantity transfer system. This electrical fault caused the gauges to freeze, leading the crew to believe they had sufficient fuel when they did not. The lack of functional testing capability via the press-to-test button prevented early detection of the gauge error. The right engine flameout was a direct result of fuel exhaustion caused by these erroneous indications.
Safety message
This incident highlights the critical importance of cross-checking fuel quantities with other available data sources, such as flight time and consumption rates, when electronic indicators fail or behave unexpectedly. Electrical faults in monitoring systems can create dangerous illusions of normalcy.