What happened
On 21 December 1997, an ATR72-202, registration G-BWTL, was operating a public transport flight from Jersey. After several failed attempts to land at Jersey due to fluctuating visibility and runway visual range (RVR) levels, the crew decided to divert to Gatwick. During the diversion, the commander requested priority handling at Gatwick, which led to the declaration of an emergency after the controller informed him that delays were expected.
While descending toward Gatwick, the commander's physical state deteriorated. The first officer observed the commander slumped in his seat, unresponsive, with beads of sweat on his forehead. For approximately four minutes, the commander was incapacitated. The first officer maintained control of the aircraft and informed Air Traffic Control of the situation. The commander eventually regained consciousness and, after a brief period of confusion, resumed his role as non-handling pilot. The aircraft completed a standard approach and landed safely at Gatwick with no fatalities and no injuries to the 50 passengers or 4 crew members on board.
The investigation
The AAIB investigation focused on the sequence of events leading to the emergency declaration and the subsequent medical episode. The investigation examined the commander's fuel calculations, which revealed that his decision to divert to Gatwick—rather than the better-weathered Southampton—was based on a calculation that suggested very limited holding fuel. This decision effectively created the fuel-critical situation that necessitated the emergency declaration.
The investigation also reviewed the crew's interaction and the commander's physiological state. While the commander's medical tests were ongoing, the investigation noted several stressors, including flight delays, fluctuating weather, and perceived friction with the first officer regarding the diversion decision. The investigation also noted that the incident was not initially reported as a serious incident by the company, meaning cockpit voice recorder evidence was unavailable.
Findings
- The commander's decision to divert to Gatwick instead of Southampton, despite the latter having superior weather and more available fuel, was the primary factor in the creation of the fuel emergency.
- The commander suffered a period of impaired consciousness lasting approximately four minutes.
- The first officer demonstrated excellent airmanship and crew resource management by managing the aircraft and communicating the medical emergency to ATC.
- Stressors including operational delays, weather fluctuations, and interpersonal tension contributed to the cockpit environment during the event.