Oh yes, I forgot that the airbus planes have the FBW which doesnt allow over rides, thanks for mentioning that.

Clear Air Turbulence happens very suddenly, and the plane just falls. It remains in level flight, but it drops anywhere from 50 feet to several thousand feet suddenly, then starts to fly normally again. CAT can't be forecast, and generally the only warning is when the plane falls, or if a plane in front of you encounters it and radios a warning.

A computer "irregularity" wouldn't have caused the drop as described by passengers. It would have pushed them into a noseover, which would have caused weightlessness for a few seconds, but it wouldn't have slammed people around like this did. Clear Air Turbulence could have caused a computer glitch post hit, but it happening prior to this incident wouldn't have caused them to do how the various passengers described.

Flaps wouldn't cause this. If the slats were deployed (which after a couple of MD-11 accidents that caused critical injuries most aircraft were designed so they couldn't on accident) then the plane would have begun oscilations where it would pitch up, then down, then back up again, but it wouldn't just drop like this. The flaps deploying would have created more drag, but they wouldn't cause a huge drop like this. I can't think of ANYTHING that could have happened on the plane that would cause a sudden and massive drop like this off the top of my head.

what if its a mixture of flaps and a clear airpocket?
Oscilations?

reports say the plane banked up, then abruptly down, what if what you said is correct, is went up, then down, and just happened to head down as it entered a major pocket, which dumped the plane?

It would have pitched back up again at the bottom and kept pitching up and down until the pilots retracted the slats. Slats are designed only for slow flight at low altitudes, in landing configuration. In high speed flight, they would slam the plane in vertical oscilations until they were retracted. That would usually mean at least two up, and two down before the crew figured out what happened. Most of the accidental deployments I heard about ended up with 5-6 cycles before they figured it out. If it was the flaps deploying, then it would have created more drag, and required them to go to a higher power setting, but it wouldn't have caused oscillations like this one went into.

Maybe ask Mr weedwacker on his thoughts.
I am no aerospace engineer, so I cannot comment much, but i still think it's some maintenance problem.
Look up Jetstar, the big Q's domestic company and see how many recent incidents they have had.

I think that QANTAS are trying to avoid being sued by offering free flights and other compensation deals to the victims.

They've stated that they are looking on a case-by-case basis to see how much they can compensate the victims.

Seriously, if QANTAS are prepared to offer compensation, then there shouldn't be a need for the passengers to sue, right?

Airline travel does have some associated risks, so it's not like QANTAS can be blamed for every single mistake. Accidents do happen. It seems like they are trying to act in good faith to appease these passengers.

Flaps wouldn't cause this. If the slats were deployed (which after a couple of MD-11 accidents that caused critical injuries most aircraft were designed so they couldn't on accident) then the plane would have begun oscilations where it would pitch up, then down, then back up again, but it wouldn't just drop like this.

The MD-11 has relaxed static stability, which obviously means the horizontal stab doesn't need to produce so much downforce, therefore it's possible to reduce the size of the horizontal stab (40% smaller than DC-10). The smaller H-stab & unstable design increases fuel efficiency significantly, in theory, allowing the plane to compete with the A330 & 777 without 'wasting' money on designing a new wing.

Obviously fighters need to be constantly corrected by a fly-by-wire system to fly properly, thus on the MD-11, to cure the designed instability they use a system called LSAS - Longitudinal Stability Augmentation System. The combination of LSAS, instability and the small H-stab, could cause oscillations, as you stated, with high speed slat deployment or, during stall, which in one incident, snapped the horizontal stabliser in half. The problem with slats was partially rectified with some cockpit improvements, and solved in 1998 when Boeing updated LSAS (These problems no longer remain and are impossible today).

On the topic of the MD-11, it was unsuccessful because it did not originally perform to expectations - resulting in many cancelled orders. The accidents did not help either. Promised performance was infact met and succeeded by 1997 through PIP and MTOW increases. It is interesting looking through reports of wire chafing that remain, but these are completely unrelated to Swiss 111. Until the 777F arrives, the MD-11F is without a doubt the best freighter in the sky.

A330 doesn't have relaxed stability, yet clearly has a more robust fly-by-wire system. I would dare say it's impossible for slats to make oscillations even if they could be deployed - that is unique to the MD-11 back in the 90's.

[edit on 10/10/2008 by C0bzz]

The reason for the slats causing MD-11 oscillations was because the handle in the cockpit for deploying them was designed so you pulled it straight down to deploy them. So several times a pilot went to put a clipboard down next to his leg, and it hit the handle, deploying the slats. They did an emergency cockpit redesign after a flight attendent was almost killed and put a locking plate behind the handle. Now you have to use both hands to deploy the slats on them.

[edit on 10/10/2008 by Zaphod58]