What happened
A Vickers Viscount was performing a passenger charter flight from Santander, Spain, to Exeter, United Kingdom. During the refueling process at Santander, the co-pilot supervised the delivery of 2720 litres of fuel. The crew relied on the flow meter readings from the refueling vehicle and the aircraft's internal gauges rather than performing a physical verification using dripsticks. At this time, both fuel quantity gauges were known to be unreliable; specifically, the port gauge had a deferred defect involving intermittent fluctuations.
The flight departed Santander at 17:33. As the aircraft progressed toward its destination, the crew noted concerning behavior from the fuel gauges near Dinard, where the port gauge fluctuated wildly and the starboard gauge showed a steady decline. Despite these irregularities, the crew believed sufficient fuel remained based on the flow meter totals recorded during takeoff. While approaching Exeter, the crew activated the fuel heaters, which triggered low-pressure warning lights. Shortly after, at approximately 19:50, both low-pressure warnings illuminated and all four engines lost power simultaneously.
The pilot attempted an emergency descent into a grassy valley to find a suitable landing site. During the forced landing, the port wing struck a tree, causing structural damage to the flap and underskin. The aircraft impacted the ground with the rear fuselage first before coming to a halt. There were 0 fatalities and 0 injuries during the orderly evacuation.
Findings
Investigation revealed that the aircraft's fuel tanks were completely empty upon inspection. The primary cause of the accident was the crew's incorrect assumption that enough fuel was available to reach the destination. This error was compounded by several factors:
- The use of unreliable fuel gauges that had documented technical defects.
- A failure to manually verify fuel levels using dripsticks.
- Inaccurate readings from the refueling vehicle's flow meters, which did not reflect the actual volume delivered.
- A lack of precise operational procedures regarding fuel verification.