A330 'glider' drama facts revealed

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Praise and blame from accident investigators for crew forced to make emergency landing at Lajes air base in 2001

The Air Transat Airbus A330-200 crew who glided their aircraft to a safe landing at Lajes air base in the Azores islands in 2001 with empty fuel tanks have been praised for their flying skill by Portuguese air accident investigators, but have also been criticised for sloppy procedures that hindered their discovery of a severe fuel leak.

The accident report observes, however, that the aircraft's electronic centralised aircraft monitor (ECAM) did not provide "a clear, unambiguous indication or warning that a fuel leak existed", and calls for it to provide a warning when any discrepancy between the engine fuel use and fuel on board (FOB) begins to develop.

The fuel leak did not start until nearly 4h into the 24 August 2001 scheduled flight from Toronto, Canada bound for Lisbon, Portugal. The leak was caused by chafing between fuel and hydraulic lines in the No 2 (right) engine that had been "mismatched" when a hydraulic pump was changed on the Rolls-Royce Trent 772B.

There is no system in the A330 for revealing fuel leaks, which have to be deduced from fuel readings. It is normal for the crew to check whether the FOB is reducing at a faster rate than engine fuel usage. Also, the report notes, the flight management control unit would show a continually reducing figure for fuel remaining at destination.

The first ECAM advisory that could have suggested a fuel leak showed there was significantly less fuel in the right wing tanks than the left. Within 2min of discovering this, the crew had opened the fuel cross feed valve and begun transferring fuel from the left wing to the right. They did not use the quick reference handbook (QRH) checklist, the report notes, explaining that, had they used it, they would have seen fuel leakage listed as a possible cause. However, the report comments: "All of the fuel-related information and messages were provided in the form of text-type status messages and digital counter displays, none of which conveyed a sense of urgency...The fact that this could occur highlights the limitations of the warning and alert system in this kind of situation."

For some time before the fuel imbalance notification, the crew had been preoccupied with an "unusual", but non-critical No 2 engine oil reading that was a secondary effect of the fuel leak.

When the crew realised how little fuel remained, they diverted to Lajes air force base, Azores. When the right engine flamed out, the aircraft was at 39,000ft (11,890m) with 278km (150nm) to go. The crew declared a full emergency just before the left engine stopped at 34,500ft, 120km from Lajes.

Lajes air traffic control provided radar vectors for approach to runway 33, and at 13,000ft on a heading of 270° with 15km to go, the captain elected to carry out a left-hand 360° turn to lose height. It was dark and there were 13 crew and 293 passengers on board.

With leading-edge slats extended, but no flaps or spoilers, the aircraft crossed the threshold at 200kt (370km/h), touched down hard 315m into the 3,315m runway and bounced once, then slid to a halt with the wheels locked by maximum braking.

Sequence of events

00:52 Take-off Toronto international airport, Canada, bound for Lisbon, Portugal

04:38 Fuel leak starts but "no noteworthy indications of fuel loss" for about 20min

05:04 Unusual No 2 eng oil readings. Extensive HF communications with base about engine oil occupied crew's attention

05:33 Fuel advisory on "ECAM TRIM TANK XFRD" (all fuel from stabiliser trim tank had been transferred automatically to the wing tanks). Unusually early in the flight for this to occur

05:34 ECAM fuel page selected, ECAM shows fuel imbalance between left and right wing tanks

05:36 Crew select fuel cross feed

05:45 Decision to divert

06:02 Cabin crew told to prepare for ditching

06:13 No 2 engine flames out at 39,000ft

06:26 No 1 engine flames out at 34,500ft

06:45 A330 lands on runway 33 at Lajes, Azores

DAVID LEARMOUNT / LONDON