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  Birtish Airways 9  

Accident Case Study

In 1982 all of what happened to British Airways 9 was unknown in aviation, the crew did everything right and as a result there were no fatalities and the airplane, though damaged, was not destroyed. The flight took off at night just as Mount Galunggung had erupted. They flew through the volcanic dust at altitude where the lessons began:

  • Volcanic ash is very dry, abrasive, and fine. When the airplane entered the dust cloud the fine, dry dust electrified with static electricity and appeared to be St. Elmo's Fire.
  • The static makes radio communications difficult, if not impossible.
  • As the dry ash enters the hot engines, it becomes a sludge that collects onto the turbine blades, fouling the airflow and eventually causing them to compressor stall and shut down.
  • After the aircraft is forced to descend the engines cool and the sludge on the turbine blades break off, allowing the engines to be restarted.
  • The powder is so abrasive that the windscreen is sandblasted and very difficult to see through.

 

images

Photo: Dramatization, from May Day.

Accident Report

  • Date: 24 June 1982
  • Type: Boeing 747-236B
  • Operator: British Airways
  • Registration: G-BDXH
  • Fatalities: 0 of 15 crew, 0 of 247 passengers
  • Aircraft Fate: Unknown
  • Phase: En route
  • Airport: (Departure) Kuala Lumpur International Airport (KUL/WMKK), Malaysia
  • Airport: (Destination) Perth Airport, WA (PER/YPPH), Australia

Narrative

Cruising at FL370 the aircraft entered a cloud of volcanic dust (Mount Galunggung had erupted). The crew noticed St. Elmo's fire and smoke and dust were present in the cabin. All four engines failed and the aircraft started to descend. The crew managed to restart engine no. 4 at FL130 and restarted the other engines in succession. Because engine no. 2 continually surged, a 3-engined emergency landing was carried out at Jakarta.

Probable Cause

Volcanic ash from an unforecast eruption fowled all four engines, interrupting air flow and causing them to shut down. Once the aircraft descended to a lower altitude the ash in the engines cooled and broke away, allowing the crew to restart the engines.

References

Aviation Safety Network

Cinder and Ash Hazards, Professional Pilot, August 2013, pgs. 86 - 90.

May Day: Falling From the Sky, Episode 27, Season 4, 22 April 2007 (British Airways 9)

Revision: 20131018
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