Sunday, December 05, 2010

Qantas Flight 32: Uncontained engine failure and damage to the aircraft

by B. N. Sullivan

This is the second in a series of posts about the events on board Qantas Flight 32, an Airbus A380 (registration VH-OQA) that experienced an uncontained failure of one of its four Rolls-Royce Trent 900 engines during flight on November 4, 2010.  The information here is based on a preliminary report by the Australian Transport Safety Bureau (ATSB), issued On December 3, 2010.

There were five flight crew on board Qantas Flight 32: the Captain (PIC); a First Officer (FO), acting as co-pilot; a Second Officer (SO); a second Captain, who was training as a Check Captain (CC); and a Supervising Check Captain (SCC), who was training the CC.

In a media briefing on the day the preliminary report was released, ATSB Chief Commissioner Martin Dolan praised the crew of Qantas Flight 32, stating that the A380 "would not have arrived safely in Singapore" were it not for the actions of the flight crew.   Reading through the ATSB report, it is clear that the entire crew really had their hands full.

Engine Failure

The ATSB report says that the first sign of trouble came during the climb out of Singapore when the crew heard two "almost coincident" loud bangs.  The PIC immediately selected altitude and heading hold on the autopilot control panel, and the aircraft leveled off, however the autothrust system did not reduce power to the engines as expected.  When it became clear that the autothrust system was no longer active, the PIC manually retarded the thrust levels to control the aircraft's speed.

The Electronic Centralized Aircraft Monitor (ECAM) system displayed an "overheat" warning message for the No 2 engine.  Then all hell broke loose on the flight deck.

Within seconds, the overheat warning changed to a fire for the No 2 engine.  The crew decided to shut down No 2 engine, and "after they had selected the ENG 2 master switch OFF, the ECAM displayed a message indicating that the No 2 engine had failed."

The crew discharged one of the engine's two fire extinguisher bottles, but did not receive a confirmation that it had discharged.  They repeated the procedure and again did not receive the expected confirmation.  They attempted to discharged the second bottle; again they did not receive confirmation that the second bottle had discharged.
The crew reported that they then elected to continue the engine failure procedure, which included initiating an automated process of fuel transfer from the aircraft’s outer wing tanks to the inner tanks.

The crew also noticed that the engine display for the No 2 engine had changed to a failed mode, and that the engine display for Nos 1 and 4 engines had reverted to a degraded mode.  The display for the No 3 engine indicated that the engine was operating in an alternate mode as a result of the crew actioning an ECAM procedure.

Shortly afterward, a flood of ECAM messages began to display.  Quoting from the ATSB report:
The flight crew recalled the following system warnings on the ECAM after the failure of No. 2 engine.
  • engines No 1 and 4 operating in a degraded mode
  • GREEN hydraulic system -- low system pressure and low fluid level
  • YELLOW hydraulic system -- engine No. 4 pump errors
  • failure of the alternating current (AC) electrical No. 1 and 2 bus systems
  • flight controls operating in alternate law
  • wing slats inoperative
  • flight controls -- ailerons partial control only
  • flight controls -- 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 a fuel jettison fault
  • center of gravity messages
  • autothrust and autoland inoperative
  • No. 1 engine generator drive disconnected
  • left wing pneumatic bleed leaks
  • avionics system overheat
Damage to the Aircraft

Unbeknown to the crew at that time, the No 2 engine's intermediate pressure (IP) turbine had failed.  The turbine disc, blade and nozzle guide vanes separated, ruptured the surrounding casing, and damaged the engine's thrust reverser.  A number of components were ejected, which struck the aircraft.

The leading edge of the left wing was penetrated, resulting in "damage to the leading edge structure, the front wing spar and the upper surface of the wing."

The left wing-to-fuselage fairing also was penetrated, "resulting in damage to numerous system components, the fuselage structure and elements of the aircraft's electrical wiring."

Damaged were "elements of the aircraft's electrical wiring that affected the operation of the hydraulic system, landing gear and flight controls; a number of fuel system components; and the leading edge slat system."

The left wing's lower surface was impacted, "resulting in a fuel leak from the Number 2 engine fuel feed tank and the left wing inner fuel tank."

[Photo Source]

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