Brent, Jeff, et al,
Here is an excerpted article on what happens if an unexpected
event occurs and there are multiple independent systems that continue to operate
the important stuff:
Scores of British passengers on board a Sydney-bound jumbo jet had a lucky
escape after the aircraft lost all electrical power as
it was approaching Bangkok airport.
In an unprecedented drama, the Qantas Boeing 747 lost vital supplies from all
four of its main generators, disabling the navigation and communication system.
Aerospace experts in Australia said today that the pilot was lucky that the
failure - caused by water leaking from a galley into the plane's
generator control unit - had happened when the plane was close to
landing.
..........with only about 30 minutes of reserve batteries remaining to
provide the vital power.
"At night or a long way from an airport, it would have been a far more
serious incident because you would have lost a lot of aircraft lighting and also
a lot of your instrumentation."
The seriousness of the power failure alarmed Dr Arvind Sinha, director of
Aerospace at the Royal Melbourne Institute of Technology, who said the jet had
"gone to the last stage of emergency power for communication and navigation".
He added: "The engines have their own independent power source and the
steering is operated by a hydraulic pump system, but the critical issues are the
navigation and communication systems that you need to find your way to a runway
to land."
Scott Krueger
AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL (KARR)
Pilot
not TSO'd, Certificated score only > 70%.