Plane seats, wing floating in Atlantic

Agence France-Presse via News.com.au ^ | June 07, 2009

[george76]

BRAZILIAN search aircraft late have spotted seats and part of a plane wing in the Atlantic where an Air France jet went down nearly a week ago, officials said after two bodies and other items were recovered from the area.

"Plane seats, part of the wing (and) various other items (were) localised,"

[expatpat]

You are correct, of course. Some of the folks posting comments on the site that G referred to are very confused. Hopefully, they are not pilots — or especially not Airbus engineers!

[UCANSEE2]

Perhaps you have a better explanation of what happened?

[UCANSEE2]

What are the possible (given the scenario) causes for the FBW Flight Controller problem?

[CheneyChick]

In the radome?

[UCANSEE2]

I’m assuming that the flight control surfaces (FBW Flight control) reacted in ways that helped the plane stall.

To be clear, I’m not stuck with the theory that extra speed caused the stall. It could just as well have been less speed, or the results of 100mph winds from a totally unexpected direction.

My main point is that it seems this crash was a result of weather conditions, and maybe some equipment malfunction.

It does not seem like a terrorist bombing, but then these things take time to get all facts possible.

[expatpat]

The ADIRU, which prepares the input data for the computers in the FCS, has a known failure history (it has had 2-3 emergency ADs in the last few months). It is surprising to me that the planes are still allowed to fly passengers with such serious ADs on a flight-critical component.

If the ADIRU fails, it feeds garbage to the computer(s) which then output garbage to the flight-surface actuators. There is no back-up to the FBW control system -- if it fails, the A/C is uncontrollable.

[expatpat]

I should add that the system does not isolate a bad ADIRU automatically, apparently, but requires the pilot to turn it off manually. In severe turbulence, the pilot may be distracted and fail to do so.

[UCANSEE2]

There is no back-up to the FBW control system -- if it fails, the A/C is uncontrollable.

Which resembles what appears to have happened to this Airbus and crew.

[UCANSEE2]

In the radome?

Good guess, but from what I have found, there is a top and bottom TCAS antenna.

[gandalftb]

Here is the actual ACARS printout:

[DuncanWaring]

1. Flying a healthy airplane in bad weather or at night is difficult.
2. Flying an unhealthy airplane in good weather is difficult.
3. Hand-flying an A330 in good weather at cruise with the autopilot disconnected is darned near impossible.

On AF447, it appears that either the pitot tubes went bad or one of the ADIRUs that was driving the cockpit displays and the autopilot went bad (or both), causing the autopilot to disconnect and depriving the pilots of critical information necessary to hand-fly the airplane.

So there they were:
a. trying to hand-fly an airplane that couldn’t be hand-flown in the best of circumstances
b. not knowing which of their conflicting sources of attitude, airspeed and altitude was correct
c. in the middle of a gawdawful thunderstorm at night

From there, it’s a short step to either getting too slow and stalling/spinning, or too fast and loosing the wings to an updraft.

[UCANSEE2]

From there, it’s a short step to either getting too slow and stalling/spinning, or too fast and loosing the wings to an updraft.

Which is pretty much exactly what I said in my posts.

It would seem the only disagreement is that I agreed with another poster that in those weather conditions, and assuming the FBW system as well as the pilots were getting incorrect sensor readings, extra speed could have led to a stall.

Note: I also believe that extra 'power' could have been added by pilots or the flight system , without producing extra speed, and therefore contributing to a stall (as in a nose up situation).