Posted on 09/16/2005 11:39:52 PM PDT by Paleo Conservative
PILOTS on a Boeing 777 from Perth to Kuala Lumpur battled to gain control of the plane last month after an unknown computer error caused the aircraft to pitch violently and brought it close to stalling.
A flight attendant dropped a tray of drinks and another began praying as the Malaysian Airlines pilots fought to counter false information being fed into the aircraft's autopilot system and primary flight display.
The glitch prompted plane manufacturer Boeing to issue a global notice to all 777 operators alerting them to the problem.
Flight MH124 was about an hour out of Perth when the aircraft began behaving erratically. The incorrect data from a supposedly fail-safe device caused the plane to pitch up and climb 3000ft (914m), cutting its indicated airspeed from 500km/h to 292km/h and activating a stall warning and a "stickshaker".
A stickshaker vibrates the aircraft's controls to warn the pilot he is approaching a speed at which the plane will have insufficient lift to keep flying.
An Australian Transport Safety Bureau report released yesterday reveals the pilot in command disconnected the autopilot and lowered the plane's nose to prevent the stall but the aircraft's automatic throttle responded by increasing the power.
The pilot countered by pushing the thrust levers to the idle position but the aircraft pitched up again and climbed 2000ft.
He notified air traffic control that the plane, carrying 177 passengers, could not maintain altitude and requested a descent and radar assistance for a return to Perth.
As the plane descended through 20,000ft, the pilot reported the primary flight display appeared normal and separately tested the aircraft's two autopilot systems.
But he was forced to keep flying manually when the plane banked to the right and the nose pitched down during both tests.
The pilot reported no difficulties flying the plane but noted that the automatic throttles remained armed.
As the aircraft was positioned to approach Perth, however, the flight display again gave a low airspeed warning and the auto-throttle responded by increasing thrust.
The aircraft's warning system also indicated a dangerous windshear but the crew continued the approach and landed safely.
Shaken passengers remained in Perth overnight and were offered alternative flights the next day.
Investigations are focusing on faulty acceleration figures supplied by a device called the air data inertial reference unit.
The device, which was sent to manufacturer Honeywell and to US investigators for examination, collates aircraft navigation and performance data from other systems and passes the information to the primary flight computer.
Boeing spokesman Ken Morton said yesterday the incident had not occurred before or since. Operators have since been told to load a previous software version.
"There is a very simple test to do before you take off and that will tell you if your system has that problem or not," he said.
"To this point we haven't had any people coming back saying they've had faults."
Mr Morton said there were 525 777s in service and they had accumulated more than 10 million flight hours and 2million landings.
"All incidents are thoroughly investigated and appropriate steps are taken to ensure the continuing safety of the in-service fleet," he said.
"Nothing is more important than that."
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bump
Fly by wire = die by wire?
Malfunction? Not me.
YARK!!!
I'll bet that was one hell of a ride.
You guys been letting Eaker fly again?
777's are not fly by wire, are they? I thought Boeing was against fly by wire.
Yes they are.
http://seattlepi.nwsource.com/business/boe202.shtml
You're right. 777 is the only model with that technology.
"Unlike Airbus, Boeing lets aviator override fly-by-wire technology"
Remember the Paris Air Show accident with an Airbus-- couldn't override the fly-by-wire? This is the old joke that came out of that:
Q: What's the difference between a chainsaw and an Airbus?
A: About 300 trees/minute
That was a great book. Somewhat down-to-earth after Jurassic Park. (pun intended.)
Just a solar flare er a rug rats iPod run amuck with the electrics I suspect.
Couldn't be a design flaw.....no way ......;o)
LOL! It was pretty good reading. After finishing the book, I took a cross-country flight and surprisingly felt more safe than ever.
The flight in the story above though would be one I would not have enjoyed.
I believe you. We've had some solar flares recently. Kids with iPods are dangerous. Yes. No way a design flaw. No way.
;-)
MS Windoze???
Captian on intercom: "everbody please recline your seatbacks fully and then return it to the upright position and let's see if this thing will reboot that way"
I thought the 757, the 767, AND the 777 were all fly-by-wire. Meaning electrical servos run the hydraulic actuators of the flight control surfaces rather than cables from the pilot's controls.
I have ultimate quantities more trust in a well-trained pilot than some silly computer that can and does hiccup for no known reason.
They just flew over someone flying their RC airplane.
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