The flight crew recalled they received the following failures:
- engine #2 failed
- engine #1 and #4 in degraded mode
- green hydraulics low pressure and low quantity
- yellow hydraulics engine #4 pump error
- failure of AC electrical busses 1 and 2
- flight controls in alternate mode
- wing slats inoperative
- ailerons partial control only
- reduced spoiler control
- landing gear control and indicator warnings
- multiple brake system messages
- engine anti-ice and air data sensor messages
- multiple fuel system messages including fuel jettison fault
- center of gravity messages
- autothrust and autoland inoperative
- #1 engine generator disconnected
- left wing pneumatic bleed leaks
- avionic system overheat
The crew discussed whether to immediately return to Singapore, climbing or holding and decided the best option was to maintain altitude while processing the ECAM messages.
The crew frequently assessed the fuel on board which was sufficient to complete the checklist procedures. The aircraft remained controllable. They advised ATC they would need about 30 minutes to process the ECAM messages and requested to hold for that period. Singapore cleared the flight for a holding east of Singapore, the flight crew advised however they needed to remain within 30nm of Singapore Airport in case they needed to land immediately. ATC advised that residents at Batam had found debris on the ground, then vectored the aircraft to a 20nm holding pattern east of Singapore Airport.
While the crew processed the ECAM messages the SO was dispatched to the cabin to assess the damage to the #2 engine. While he walked through the cabin a passenger, also Qantas pilot, pointed out that pictures from the vertical fin mounted camera suggested a fluid leak from the left hand wing. The SO walked down to the lower deck of the passenger cabin and observed damage to the wing and a fluid leak that appeared to be about 0.5 meters wide. He could not see the turbine area of the engine from any position in the cabin. The SO returned to the cockpit and reported his observations.
The crew stopped re-arranging the fuel system doubting the integrity of the system. They could not dump fuel due to the fuel jettison error message. The operator sent ACARS messages that they had received multiple ACARS messages indicating various system failures from the automatic reporting system, the crew was busy with the ECAM messages and found time to just acknowledge the ACARS transmissions.
The PIC and SSC made a number of announcements to the passengers advising that they had technical problems, they were working to address these issues and it would take some time to do so. Subsequently the SO and SSC went to the cabin frequently to check the left hand side of the aircraft and to provide feedback to cabin crew and passengers.
It took about 50 minutes to complete the checklist procedures associated with the ECAM messages. During that time the autopilot was engaged. The crew then assessed which systems were operative, degraded and failed and discussed the impact on landing performance. They also believed that engine #1 may have been damaged and discussed a number of concerns regarding fuel imbalances that had been indicated by the ECAM.
The crew determined their landing weight would be 440 tons, about 50 tons above maximum landing weight, and computed the required landing distance with the systems available. The computation showed, that a landing on runway 20C was feasable with 100 meters of runway remaining. The crew elected to proceed on basis of this computation and advised ATC accordingly. The crew advised further they needed emergency services at the upwind end of the runway, fluid was leaking from the left wing that was likely to include hydraulic fluid and fuel.
Prior to leaving the holding pattern the crew discussed controllability of the aircraft and performed a number of manual checks at the holding speed. The crew requested a 20nm final to runway 20C to commence from 4000 feet, ATC fulfilled that request.
While the crew began the approach and lowered flaps they conducted further controllability tests at the approach speed and decided the airplane was controllable. The landing gear was lowered using the emergency extension procedure, a further controllability check was conducted.
The approach speed was computed at 166 KIAS. The crew was aware that reverse thrust was available only from the #3 engine, no leading edge slats were available, there was limited aileron and spoiler control, anti-skid was restricted to the body gear only, there was limited nose wheel steering and the nose would likely pitch up on landing. An ECAM message indicated they could not apply maximum braking until the nose wheel was on the runway. The flaps were extended to position 3.
ATC vectored the aircraft for a 20nm final progressively descending the aircraft to 4000 feet, the PIC was aware that speed control was necessary to avoid an aerodynamic stall and a runway overrun. Consequently the PIC set engine #1 and #4 to symmetric thrust and controlled the speed of the aircraft with the #3 engine. The autopilot disconnected a number of times during the initial approach, the airspeed dropped to 165 KIAS. The PIC reconnected the autopilot a number of times but when the autopilot disengaged again at 1000 feet he decided to fly manually for the remainder of the flight. Due to the limited runway margin available the CC reminded the PIC that the landing had to be done without flare and there would be a slightly higher nose up attitude during touch down.
The flight crew briefed the cabin crew for a possible runway overrun and evacuation.
The airplane touched down on Singapore's runway 20C 109 minutes after departure and within 6 seconds the nose wheel touched down and maximum braking was applied, reverse thrust was selected on the #3 engine. The crew felt that initially the deceleration was slow but with maximum braking and reverse thrust the airplane began to decelerate. The PIC felt confident the airplane would stop on the runway after the airplane had decelerated to 60 knots, and moved engine #3 gradually out of maximum reverse thrust. Manual braking was continued and the airplane stopped about 150 meters before the runway end.