Air France 447 Found

[jonjuan]

Does anyone here know the Airbus flight control logic to know if that's even possible with that airplane's FBW system?

I don't think that has anything to do with pilot skill or training....but it has everything to do with what the pilots would be able to do with the controls when the ADC isn't getting accurate data.

Watch the show on Nova (online) which forensically recreates what they surmise may have happened. The also look at historical data in which previous pitot tubes froze yielding innacurate airspeed data. In a number of the cases, it took crews a long time to respond to low thrust settings (maybe in part because the thrust levers don't move on the bus when dialing in a reduced airspeed?)

 

[Mud Eagle]

Does anyone here know the Airbus flight control logic to know if that's even possible with that airplane's FBW system?

Sure you can. Pitch and power.

Yeah, I understand the concept of pitch and power, thanks.

What I was asking was that, if the pitot system iced over, as is the hypothesis in the NOVA episode, and thus the ADCs would be getting false data, and the flight control and engine computers would be making decisions based on that false data, would the pilots still be able to set known pitch and power settings?

Would the pilots be able to select a throttle position that would give a known power setting? Would the stick inputs actually be turned into flight control movements?

In other words, to what extent can actual manual inputs (over-riding what the computers 'want' them to do) be made to an Airbus' flight control system and engine power system?

 

[BoeingBaller]

Every thread on here turns into a bitchfest...

 

[GuppyWN]

What defense will they have if it shows the airplane was fine until it flew into the top of a thunderstorm?

The same one they have now. But if it somehow shows the problem is an Airbus problem...........

Gup

 

[airjackson]

http://www.pbs.org/wgbh/nova/space/crash-flight-447.html

If you haven't seen it, it's worth watching.

 

[IBNAV8R]

So, based on the speculative NOVA theory. They either:

Could have flown pitch and power (attitude flying) but didn't.

Tried to fly pitch and power but couldn't.

Air France or Airbus?

I'm anxious to see what the real story turns out to be.

 

[jonjuan]

What I was asking was that, if the pitot system iced over, as is the hypothesis in the NOVA episode, and thus the ADCs would be getting false data, and the flight control and engine computers would be making decisions based on that false data, would the pilots still be able to set known pitch and power settings?

Would the pilots be able to select a throttle position that would give a known power setting? Would the stick inputs actually be turned into flight control movements?

In other words, to what extent can actual manual inputs (over-riding what the computers 'want' them to do) be made to an Airbus' flight control system and engine power system?

The Nova episode has a crew deal with the same emergency (as known from fault data sent). With the numerous faults given to them (including lack of airspeed and air data faults), the are still able to maintain control through a pitch/power setting combination. What's implied in the episode is that with everything gone, they should have been able to maintain control (although they cannot be certain until the data recorders are recovered). What they used to come to the hypothesis is that there has been quite a few instances where crews in the airbus have been slow to recognize reduced thrust settings (not sure how this system is different than on a Boeing).

 

[b707guy]

Pitch and power day VMC is one thing, but pitch and power at night, in a rockin' thunderstorm when you may not have been expecting it is another. None of us was there, thankfully, and I'm not trying to guess what happened. All I do know from years of crossing the ITCZ at night at relatively low altitudes, (we cross the main routes from SA to Europe on our run, so we are always held down, 30-32k) is that I absolutely dread the moonless nights, even more so when there are clouds maybe hiding those embedded storms and buildups. We do know that is was a nasty night that night, but I have hit the tops of things that had gone unseen and which didn't show up on radar on relatively quiet nights. Those sure get your attention.

And just because two aircraft passed through minutes earlier doesn't mean it was safe for the last one, as Delta found out the hard way in DFW back when windshear was beginning to be recognized and understood (1986+/-?).

 

[Dornier 335]

One more thing that got me thinking after watching the Nova episode: What if the turbulence is so severe that you cannot clearly read your instruments? In this case to maintain pitch and power? I had never thought that it could be impossible to clearly read my instruments but happened to me twice due to mountain waves. Add darkness, iced pitot tubes, super-cooled water droplets, radar shadows... ugh!

 

[flythere]

Have never flown a Bus, do they have an angle of attack indicator? If so, is that information displayed on a PFD/HUD? Does it display information independant of the Air data computer?

I wonder if that could have been valuable info for the pilots when they lost airspeed indications?

Have read a book on the Edmund Fitzgerald, which sank on the great lakes back in the 70's, in only 530 feet of water. Apperently after 10+ years in the very cold depths of Lake Superior, they found bodies still in good shape, all thing's considered.

 

[Jim Smyth]

I think they did a great job on the analysis on Nova. I am glad they found the wreckage on the bottom of the Ocean finally and hopefully can piece this all together with the newer clues.

Back in the late 80's Midway Airlines went with new MD-80's and taught full up systems. They wanted everyone to use all the automation all the time. After a year when guys started coming back for there recurrent training we found out most guys lost a good portion of there proficiency flying the airplane manually. Training at the time changed there ideas and instructed the guys to go back and do more hands on flying to stay sharp.

I have never flown an air bus but with all the automation and he fact the throttles don't move at all (Big Mistake IMO on Air Bus's part) I can see where guys can get complacent with there flying skills. Couple that with middle of the night flying where your tired and not thinking the clearest and bad weather where that back line of thunderstorms was blocked out by the echo's on the first cell, lightning in your face and hardly being able to see the instruments because of turbulence was as good of an explanation as you can get for loss of control of the airplane.

Unfortunately we all learn from either the mechanical malfunctions in airplane disasters or the Pilots that make crucial mistakes at the wrong time. My generation of pilots is retiring now and we were more the seat of pants type of flying. The newer generation is the more technical type of Pilot with full automation. I hope the younger generation learns from these mistakes and continues to keep there hands on flying skills honed so if/when this happens again you will be equipped to have a better outcome than Air France did.

 

[wmuflyguy]

What they used to come to the hypothesis is that there has been quite a few instances where crews in the airbus have been slow to recognize reduced thrust settings (not sure how this system is different than on a Boeing).

I think it has to do with "Autothrust" in the Airbus vs. "Autothrottle" in a Boeing.

In the Airbus the Thrust levers stay in a detent and don't move regardless of the thrust setting. In an Autothrottle aircraft the thrust levers move with reference to the thrust commanded. So with a hand resting on the thrust lever you can get a feel for what thrust is set and what the computer is doing.

Along the lines of Basic Attitude flying, Aeroperu 603 was another accident where they had no pitot static instruments, with the clacker going off. Flew around in the shaker with the gpws going off. Over the ocean on a dark night. Unfortunately didn't end well either. They couldn't tell what was real or not with the conflicting warnings.

 

[machophil]

Yawn ... Ever heard of the weather phenomenon called the ITCZ? Ever talked to pilots who cross it on a regular basis? Besides, LH and IB had both crossed the approximate location without any problems just a few minutes prior.

http://www.bea.aero/docspa/2009/f-cp090601e1.en/pdf/f-cp090601e1.en.pdf

page 67, crews in the vicinity all reported significant thunderstorm activity. They made large deviations off course, experienced St Elmo's Fire, moderate turbulence, and communication difficulty with ATC.

 

[Lear70]

In the Airbus the Thrust levers stay in a detent and don't move regardless of the thrust setting. In an Autothrottle aircraft the thrust levers move with reference to the thrust commanded. So with a hand resting on the thrust lever you can get a feel for what thrust is set and what the computer is doing.

Yet another reason to avoid flying an Airbus product.

Call me crazy, but I like to know exactly what the **** the aircraft is doing when my hands are on the controls.

 

[wmuflyguy]

Yet another reason to avoid flying an Airbus product.

Call me crazy, but I like to know exactly what the **** the aircraft is doing when my hands are on the controls.

Yea, I just recently started flying an aircraft with autothrottles about 2 months ago. I already find my self trusting them more than I would like.

Question for Airbus people, can you guys over ride the thrust (bump it up, if you get a bit slow) without disengaging the autothrust? My only experience is JS'ing on them and I never saw the pilots do this, seems like we over ride them quite a bit in the Embraer on approaches, not sure if our at system is just weak though.