Air france flight from Brazil to Paris

[RabidAlien]

If it were terrorists, it would've been someplace a lot more visible. They're not after mystery and intrigue. They're after publicity. It would've gone down over an airport or populated area somewhere. Al Ka'holik can't claim credit for something nobody sees, and expect to gain anything by it (not that they gain anything except international loathing anyway).

 

[Gnomey]

True RA and with latest news about Air France speeding up the replacement of speed sensors on their Airbus's then it is looking more and more like a stall to me. The way the news has panned out I think they had an inclination it was a stall all along because first the news that pilots must speed up in storms and now the increase in the rate of replacement of the speed sensors. I guess we have to wait for the definitive results from the black boxes if they ever find them but the investigators seem to think it was a stall if I am interpreting the news correctly.

BBC NEWS | Americas | Air France replaces speed sensors
BBC NEWS | Americas | The tortuous search for Air France crash clues

 

[syscom3]

One alternative is this was a criminal act, but not for terroristic [political] purposes. Perhaps a black mail attempt? Narco terrorists branching out to other lucrative fields?

As for the stalling, why would that cause the plane to fall apart in mid air?

And I dont know anything of the airplanes systems, but arent there more than a couple of pitot tubes that are part of the design? If one is damaged, then the others should work.

 

[FLYBOYJ]

As for the stalling, why would that cause the plane to fall apart in mid air?

It depends on how abrupt the stall was. Remember, they were in adverse weather and if they were in an excessive attitude, be it bank or pitch, the pilot could have inputted control responses that could have put stress on the airplane (and no fault to the pilot in this situation). If you put extreme control inputs into airliners you will cause damage - case in point - American Airlines flight 191.

And I dont know anything of the airplanes systems, but arent there more than a couple of pitot tubes that are part of the design? If one is damaged, then the others should work.

I think the several pitot tubes may have taken an "average" of indications and the computer will determine if one is operating in error, but if they were all iced over any computer would have received errors regardless.

 

[vikingBerserker]

How would a stall kill all electrical power though?

 

[FLYBOYJ]

How would a stall kill all electrical power though?

It won't unless structural failure caused a catastrophic failure in the electrical system

 

[Vassili Zaitzev]

Must of been freightening, been caught in a storm, and all of a sudden the stall warning sounds. I guess we won't know for certain until the black boxes have been found, if they are found.

 

[seesul]

More bodies recovered...
Air France Plane Crash: More Bodies Recovered From The Atlantic Ocean | World News | Sky News

 

[DerAdlerIstGelandet]

Man I love when the conspiracy theorists come out. There is absolutely no reason to believe that this was a terrorist or criminal act. All signs are showing toward either:

1. Caused by the severe weather in the area.
2. Some of kind of mechanical or system failure.
3. Or a combination of both...

There is absolutely no reason to believe that this was a terrorist attack or a crime. Sorry I do not understand why people even come up with such things. I guess it is because everyone wants to act like the press "experts" when something like this happens.

Oh well, only time will tell...

It depends on how abrupt the stall was. Remember, they were in adverse weather and if they were in an excessive attitude, be it bank or pitch, the pilot could have inputted control responses that could have put stress on the airplane (and no fault to the pilot in this situation). If you put extreme control inputs into airliners you will cause damage - case in point - American Airlines flight 191.

Come on Joe, that is not possible! Computers and automated cockpits don't make mistakes! Ain't that right Sys?

 

[muller]

I caught the tail end of an interview with an Aer Lingus pilot on the news this eveneing, he was talking about the speed sensors on the airbus failing and the flight control system not knowing what speed the aircraft was going and hitting 'coffin corner'. Just googled it.


Wiki- Coffin Corner.

"The coffin corner or Q-Corner is the altitude at or near which an aircraft's stall speed is equal to the critical Mach number, at a given gross weight and G loading. At this altitude the aircraft becomes nearly impossible to keep in stable flight. Since the stall speed is the minimum speed required to maintain level flight, any reduction in speed will cause the airplane to stall and lose altitude. Since the critical Mach number is maximum speed at which air can travel over the wings without losing lift due to flow separation and shock waves, any increase in speed will cause the airplane to lose lift, or to pitch heavily nose-down, and lose altitude. The "corner" refers to the triangular shape at the top of a flight envelope chart where the stall speed and critical Mach number lines come together."

Consequences.

"When an aircraft slows to below its stall speed (or more properly, when the wing exceeds its critical angle of attack), the airflow over the top of the wing separates from the wing surface, and lift decreases dramatically (the wing "stalls"). Because the lift reduces while the aircraft's weight does not, the aircraft loses altitude. When the aircraft exceeds its critical Mach number, then drag increases or Mach tuck occurs, which can cause the aircraft to upset, lose control, and lose altitude. In either case, as the airplane falls, it could gain speed and then structural failure could occur.

As an aircraft approaches its coffin corner, the margin between stall speed and critical Mach number becomes smaller and smaller. Small changes could put one wing or the other above or below the limits. For instance, a turn causes the inner wing to have a lower airspeed, and the outer wing, a higher airspeed. The aircraft could exceed both limits at once. Or, turbulence could cause the airspeed to change suddenly, to beyond the limits."

 

[Matt308]

Below are the messages tied to coded ATA-JASC codes with time. Note that where the messages codes do not match my ATA-JASC codes, I have only included the major ATA-JASC chapter, but could not find the subchapters. You might have more luck. Also not being completely familiar with the A330 autoflight/autothrottle system acronyms, I have flagged those where I was guesstimating message content.

The ATA-JASC codes/time indicate in rough order:

May 31st
2245
Water Waste/Wast Disposal System Maintenance Status warning
Water Waste/Wast Disposal System (message content unknown to me) references Lavatory and likely Lavatory location (X2?) failure


June 1st
0210
Pitot Probe failure
Air Temp Indicator/Sensor failure
Auto Flight System warning
Auto Flight/Autopilot System Off warning
Auto Flight (ATA 27-93?) Alternate Control Law warning
Auto Flight (ATA 22-83?) Flags on both Capt/FO Primary Flight Display warning (autopilot disconnect flags) warning
Auto Flight/Auto Throttle System Off warning
Navigation/Doppler System (ATA 34-43?) Navigation TCAS Fault warning
Auto Flight (ATA 22-83?) Flags on both Capt/FO Primary Flight Display warning (autothrottle disconnect flags) warning
Flight Controls (ATA 27-23?) Flight Control Rudder Travel Limiter Fault warning

0211
Navigation/Outside Air Temp Indicator-Sensor Flag on Capt/FO Primary Flight Display warning
Two failure messages ATA 34-12 Navigation/Outside Air Temp Indicator-Sensor (Message content unknown to me. IR1, IR2, IR3 Inertial Reference Unit failures perhaps?)

0212
Navigation/Flight Environment Data - Navigation ADR (Air-Data Intertial Reference Unit?) Disagree warning

0213
Two warning messages for Flight Controls (ATA 27-90?) Flight Control Primary/Secondary Fault
Autoflight (ATA 22-83?) message content unknown to me. AFS=Autoflight System?

0214
Navigation/Flight Environment Data Maintenance warning
Air Conditioning/Cabin Pressure Controller warning

 

[syscom3]

Come on Joe, that is not possible! Computers and automated cockpits don't make mistakes! Ain't that right Sys?

You score a point

 

[Matt308]

Also note that the ACARS messages summary are public domain. This is NOT considered any of the sensative accident information deemed not suitable for public consumption at this time.

 

[The Basket]

If the pitot tubes were all frozen then the pilot wouldn't know his altitude or his speed.

He would have no visual references either.

If the aircraft had somehow entered into a steep dive but still not with the idea it broke up in midair. But the pilot was flying blind with all sorts of whistles and buzzers blaring.

There was a case of a South American airliner which had all its pitots taped up and the pilots ended up flying it into the ground at night. They had no idea what was going on. If you're told to trust your instruments and they go all crazy in zero visibilty then you're donald ducked.

 

[Matt308]

And the ACARS messages would support that hypothesis.

 

[Burmese Bandit]

Which brings us to the question: are not modern aircraft, and aircraft built to the Airbus design philosophy in particular, specifically built so that this sort of thing can not happen?

 

[Matt308]

CAN NOT are strong words, BB. Modern air transport airplanes are built with fault tolerant systems. These systems have triple and quadruple redundancy built into them, as well as dissimilar designs to minimize common mode failures. But a system which 'CAN NOT' fail has never been been designed...Only the likelihood of that failure occurring minimized to an 'acceptable' level. And that equates to $$$. The dirty secret in the accident/incident investigative world is that deaths=$$$ when evaluating cost analyses for aircraft designs. And some deaths are actually 'acceptable'. Folks may not wish to believe this, but it is true. I know first hand.

 

[Vassili Zaitzev]

Basket, you're talking about Aeroperu flight 603. Their static ports were covered with duct tape during cleaning, and were never taken off. The CVR recordings are on youtube. They had multiple alarms going off with no visibility. The pilots had no idea what their altitude was, until they hit the water.

So I guess in essence, these two flights are similar. Both planes had problems with their instruments, and the pilots had no visibility.

 

[syscom3]

I believe the flight panel does have a traditional artificial horizon and altimeter for the pilot to use in case the digital display blanks out.

It seems quite likely that the plane did stall due to the pitot tubes freezing. But a stall in itself shouldn't cause the aircraft to breakup.

 

[gumbyk]

It seems quite likely that the plane did stall due to the pitot tubes freezing. But a stall in itself shouldn't cause the aircraft to breakup.

Would a stall/spin situation lead to a break-up? I can't imagine that something of that size would last too long with the forces generated in a spin.