The first sign something had gone very wrong came in the form of two loud bangs. A chunk of metal tore through the plane’s wing, the aircraft yawed and a flood of emergency warning messages in the cockpit of the Qantas superjumbo sent the crew scrambling into action.
A preliminary report released on Friday by the Australian Transport Safety Bureau laid out the first official, detailed account of what happened after the mid-air disintegration of a Rolls-Royce engine on the Qantas A380 shortly after takeoff from Singapore on November 4.
The report confirmed earlier suggestions that an oil leak was the likely culprit of the blowout in what was the most significant safety issue for the world’s newest and largest jetliner. It also showed the dire conditions the pilots faced as they manoeuvred the battered Airbus plane towards the ground for an emergency landing that could have ended in disaster.
“The aircraft would not have arrived safely in Singapore without the focus and effective action of the flight crew,” ATSB chief commissioner Martin Dolan said.
The bureau said a suspected manufacturing defect in an oil pipe deep within one of the plane’s four Trent 900 engines may have led to an oil leak in an extremely hot part of the engine. That could have sparked a fire that caused a disintegration of one of the engine’s giant turbine discs. Pieces of the disc shot through a wing, severing electronics and causing an avalanche of problems for the five experienced pilots on board.
The Australian agency, which is leading the international investigation into the Qantas engine breakup, recommended new safety checks for A380s using the Trent 900s. Twenty-one A380s are powered by those engines for three airlines, Qantas, Singapore Airlines and Germany’s Lufthansa.
Qantas, which grounded all six of its A380s for 19 days after the blowout, said on Friday it completed the new checks on one of the two planes it returned to service and found no problems. The others are still undergoing tests. Singapore Airlines, which has 11 A380s, also said it was conducting new checks on its engines.
Lufthansa said only one of the Trent 900 engines on its four A380s was from the same series as the one on the Qantas plane. It replaced that engine on Friday with a modified version now being produced by Rolls-Royce, it said.
According to the bureau’s report, the Qantas flight took off normally. At about 7,000 feet (2,100 meters), the crew heard two loud, almost simultaneous bangs. The plane yawed slightly before levelling off again. Inside the cabin, several passengers looking out their windows saw flames streaming from the engine. Debris was raining onto Indonesia’s Batam island below.
In the cockpit, the pilots watched as emergency warning messages filled a computer screen- There was an “overheat” warning in the Number 2 engine, followed by a “fire” warning. The wing slats were inoperative and the plane’s auto-thrust and auto-land weren’t working. There were warnings about the brakes and landing gear, the engine’s anti-ice mechanism, the plane’s centre of gravity.
The crew shut down the engine and discharged one of its two fire extinguishers. But they were given no confirmation the extinguisher had worked. They tried again, to no avail. They moved on to the second fire extinguisher. They still received no confirmation it was working.
More warnings followed- The plane’s satellite communications system had failed. And the plane’s Number 1 and Number 4 engines had reverted to a degraded mode, restricting the flow of information.
The crew hurried to sift through and respond to the growing sea of messages, a process that took about 50 minutes. Meanwhile, the second officer walked into the cabin to get a better look at the Number 2 engine and saw fuel leaking from the damaged left wing.
Landing the plane would be tricky- Reverse thrust, which slows the plane down on the runway, was only available from one of the four engines. Yet another message warned the pilots not to apply maximum braking until the plane’s nose wheel was on the runway.
In those conditions, the pilots knew there was a chance they’d overrun the runway. The pilots warned the cabin crew to prepare for that possibility, and to be ready for an evacuation.
The autopilot disconnected a couple times during the plane’s early approach, but a crew member managed to reconnect it. With just 1,000 feet (305 meters) to go, it disconnected again, leaving the captain little choice but to fly the aircraft manually for the rest of the approach.
The plane touched down and the captain applied maximum braking. With only one engine using reverse thrust, the plane was going fast, but eventually began to slow.
It finally came to a stop less than 500 feet (150 meters) from the end of the runway.