Crew finger trouble over fuel management at the end of trip marred a text book operation
No finger trouble on the crews part. From the report
Although the fuel system was fully described in the aircraft manuals, the operator’s fuel balancing procedures were different from that of the manufacturer.
The crew had been using the override/jettison pumps to maintain fuel balance but these became ineffective towards the end of the flight. Thereafter, there was a reluctance to turn both main pumps off in a tank and a lack of confidence that this would be effective. There was increasing concern that they would not be able to keep the main tanks balanced and that some of the fuel might be unavailable.
A better understanding of the fuel system should have reassured the crew that fuel should have been avialable to all engines even with one tank empty. Nevertheless, the awareness of the apparent problem came at a time when the crew had made the decision to divert, had started the descent to Manchester and was therefore busy. If the crew had been in the habit of utilising the manufacturer’s procedures for balancing fuel by only using the main pumps, it is possible that they would have become more confident with the procedure. Although the problem had not previously been encountered by other company pilots, the potential difficulties might have been foreseen by the operator. After the incident, the operator reverted to the manufacturer’s fuel handling procedures.
The operator has a training programme for pilots who are qualified to carry out planned 3-engined ferry flights, the emphasis of which rightly concentrates on the takeoff. Additionally, all flight crews are subject to regular simulator evaluation of 3-engine handling. However, this later training is necessarily limited in time and crews are not normally subject to an extended period of 3-engine flight with the associated fuel balancing requirements. It is therefore recommended that the operator include relevant instruction on 3-engined fuel handling during initial and recurrent training.