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."
Is that a photo of Boeings 707 being barrel rolled by their chief test pilot "Tex" over Boeing Field in 1958?
Actually, it's "Everybody release your seatbelts and then, on my command, relatch them."
Well....somewhere in there you'll probably find '=' where '==' should be....
I would still rather be in a 777 than any other plane.
"The autopilot has deflated!"
Yes.
The pilot finally was able to recover at about 5000 ft and got it on the ground at Gander. The acft was so badly stressed, it was scrapped.
LOL!
Well if I'm on a plane doing that they will be at least 1 click short of a reset...
Ruh-Roh.....
Mayday,Mayday,......
I'm going in......
Boeing: That's not a bug. It's a feature!
Bump!
Could also be a bent pitot tube, or it's being blocked somehow.
"In Boeing's philosophy though, they went the conservative route and still left it up to the pilot in the end , the control and judgment up to the pilot."
I have also heard it called "actualization by wire" which is why I was surprised it was even called fly-by-wire (usually considered an Airbus differentiator). I would think most Americans prefer giving ultimate control to the pilot.
I went on a flight test of a new 777-200LR before certification. Even with a stripped down interior and the variety of tests going on such as A/C and smoke (cough, cough) going on, it was a quiet, impressive ride. From Seattle down to SF, back to Seattle, to Glasgow, Montana, to Seattle, to SF, and finally back to Seattle (approx 10 hr). The in-flight pax entertainment system was great as well with the GPS monitors that show where the plane was at any time.
Can't wait for the 787.
I think it is all semantics. "Fly-by-wire" is often considered an Airbus differentiator, while Boeing calls it "Actualization by wire".
I think most people would rather leave the ultimate control up to a trained pilot because we know how easily computer electronics can fail.
Sounds like a hippie techno meditation thing.... I can see why fly by wire terminology is used.
Kind of funny, depending if you are looking at it from a physics (actuator) or social (self-actualization) viewpoint.
http://en.wikipedia.org/wiki/Actuator
http://en.wikipedia.org/wiki/Self-actualization
Fly-by-wire sounds like "fly-by-night", not reassuring either.
True... still an improvement over flying by the seat of your pants, I suppose.
I think the pic in post # 2 is the Boeing Test Pilot Tex Johnson's perfect dutch roll on the original flight ?
Tough airframe.....
Hard to indict the FBW since the FDR was swapped. The pilot, who did jail time, claims that the engines didn't respond when TOGA power was applied.
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