Men Who Killed Qantas - Matthew Benns [100]
Second Officer Mark Johnson was dispatched aft to look at the number two engine from the passenger cabin. As he did so, a fellow Qantas pilot, who was travelling as a passenger, drew his attention to the in-flight entertainment system, which was showing a feed from a camera mounted outside on the plane’s own vertical fin. A half-metre-wide trail of fuel could be seen leaking from the wing. The plane had been loaded with an extra two tonnes of fuel to allow it to track around the active Merapi volcano in Indonesia. The failure of the fuel jettison system meant they could dump none of it and were faced with the prospect of an emergency landing overladen with highly flammable aviation fuel. The second officer returned to the flight deck and reported that the engine was ‘stuffed’, and the crew began a 50-minute inventory of exactly what was working on the A380 – the same aircraft that just two years before had been the very first to be delivered, amid great fanfare, to Qantas from the French Airbus factory in Toulouse.
What the flight crew did not know, and what investigators would only piece together much later, was that the Rolls-Royce A Series Trent 900 engine had suffered a catastrophic failure. A Trent jet engine has 18,000 parts working furiously in the equivalent of a superheated flying furnace. The turbine blade sits in a disc that rotates at 10,000 revolutions per minute – exerting pressure equivalent to having a double-decker bus hanging from its tip. The gas inside the turbine is at least 400 degrees higher than the melting point of the blade’s alloy. Into this burning maelstrom is pumped a constant stream of highly flammable aviation fuel from the 310,000 litres stored in the wings. If only one part fails, it all goes spectacularly wrong.
On QF32, a misaligned counter bore in a tiny oil-feed stub-pipe just 1.5 centimetres wide had led to fatigue and cracking on one side of the pipe. The pipe feeds cooling lubricating oil to the high-pressure and intermediate-pressure bearings in the turbine. When oil leaked from the faulty pipe, the bearings overheated and the engine caught fire. The Australian Transport Safety Bureau (ATSB) preliminary transport safety report said the engine had ‘sustained an uncontained failure of the IP turbine’.6 What that meant was that the powerful jet engine’s rapidly spinning turbine disc, blade and nozzle guide vanes had disintegrated into deadly metal shards that ripped through the engine’s casing and engine cowls, causing enormous damage. Jet engines are designed to contain all the debris they create in the event of a major failure. This one didn’t. The spewing shards of metal cut through the leading edge of the left wing, damaging the structurally important front wing spar and upper surface of the wing. A whirling piece of turbine disc pierced the left wing’s wing-to-fuselage fairing, cutting vital electrical wiring and system components. Other shards hit the underside of the wing, causing fuel leaks from the number two engine fuel-feed tank and left-wing inner fuel tank. Other engine parts rattled off the plane’s pressurised fuselage. Engineers would later find severed electrical cables that were vital to the control of the hydraulic system, landing gear, flight controls; a number of fuel system components; and the leading edge slat system.
On the flight deck, Captain de Crespigny and his colleagues were trying to work out all this from the alarms and warning messages lighting up their control panels.