Low Fuel

Air Safety Week, March 14, 2005

There is more to the story of the British Airways [BAB] B747 that flew from Los Angeles to England on three engines (see ASW, Feb. 28). The number 2 engine suffered a compressor stall after takeoff, was shut down, and the crew expected a landing back at Los Angeles International Airport. In anticipation of such, they headed out over the water to dump fuel. They were also on the radio with flight operations back in England. The maintenance experts, who had access to engine data, determined that no extra damage would occur to the engine with continued flight, so the crew set off for London on the remaining three engines.

With delayed routing, they did not get optimum flight levels for the journey, faced stronger headwinds than expected, and were limited to 29,000 feet on three engines, anyway. Moreover, at the top of descent, despite having minimum fuel on board, they could not get the fuel out of the number 2 tank (number 2 engine was shut down, remember).

They declared a Mayday and landed uneventfully at Manchester, about 160 miles short of London. Why couldn't they get the fuel out of tank two? As we understand it, the level had fallen to 3.2 tons and the override pumps had automatically shut down. A FUEL QTY LOW message comes on when any main tank gets down to 900 kg. The checklist includes instructions to land at the nearest suitable airfield, and to avoid high nose up attitudes and/or excessive accelerations. That may well explain the crew's Mayday call and the statement to Manchester that they were not able to go around.

Upon landing, with 5 tons remaining, the fuel synoptic would have 3.2 tons in the failed engine's tank and 0.6 tons in each of the others. The 3.2 tons is still useable, it is just that # 2 tank pumps are as strong as the other engines', and so will override them when one of them stops working (i.e., a fuel port becomes uncovered). So the tank #2 fuel was only "presently" unusable, but the pilots would not have been in a position to know that for sure, short of turning off all pumps on one of the working engines to see if the fuel transferred, and that would doubtless have been stressful, gravity/suction/dihedral feed or not.

It is notable that if they'd straightaway proceeded on a climb toward the UK and consulted the home office en route, instead of circling over the Pacific Ocean west of Los Angeles for over 20 minutes, they probably would have had enough fuel to make Heathrow - and no one would have been any the wiser.

There is some speculation that the flight was continued from Los Angeles to London because a new European Union (EU) regulation requires that passengers be compensated if a flight is canceled. British Airways officials deny that this was a factor in the incident.

The engine was replaced, but the replacement engine failed six days later, three and a half hours out on a flight from Singapore to Heathrow. The flight continued on three engines to Heathrow. To be sure, a long list of safety considerations must be met for any decision to continue on three engines, but nevertheless the policy is under "intense scrutiny" at the moment.

The UK's Air Accidents Investigation Branch (AAIB) is investigating the first incident, and its findings will be presented in this publication when they are published. Meanwhile, the Federal Aviation Administration (FAA) is making ugly noises about fining British Airways for "careless and reckless operation of an aircraft," even though the B747 is approved for continued flight with one engine out. However, we suspect that the problem the FAA will be forcing down their throats is that it was an abnormal operation and that continued flight to destination under those conditions is not envisaged as any sort of standard. For what it's worth, the relevant FAA regulation is presented.

On any analysis, dumping fuel and returning to the departure airfield for a high weight landing is more risky (albeit a very small one) than flying on three engines for 12 hours. In the last four hours of the flight over the North Atlantic, the power to weight ratio of the aircraft on three engines would be the same as four at top of climb.

That said, and with the benefit of hindsight, perhaps the BA jet could have landed at O'Hare or John F. Kennedy International and spent the time en route getting the passengers set up for onward connections.

Regulation (EC) No. 261/2004 of the European Parliament, Feb. 11, 2004

Establishing common rules on compensation and assistance to passengers in the event of denied boarding and of cancellation or long delay of flights:

* Action by the Community in the field of air transport should aim, among other things, at ensuring a high level of protection for passengers (extracts).

* Denied boarding and cancellation or long delay of flights cause serious trouble and inconvenience to passengers.

* The Community should therefore raise the standards of protection ...

* Passengers whose flights are cancelled should be able either to obtain reimbursement of their tickets or to obtain re-routing under satisfactory conditions, and should be adequately cared for while awaiting a later flight.