French passenger jet gone missing from radar screens........

[just me]

Chilling. I am a private pilot and I am terrified of the sink rate when I don't watch my airspeed on approach. It's what I pay attention to the most. When you are that low to the ground, you can't point the nose down to gain airspeed, and increasing power can not generate lift if it does not change the angle of attack and therefore the speed of airflow past the wings. Quite a few airplanes have crashed because they settled back to the ground under full power.

I wonder if commercial airliners can get tracking/telemetry from satellites and display that as an alternate set of reference data for pilots. If this data indicates something that does not reconcile with the plane's own measuring systems, it would indicated a potentially deadly trim situation.

1. Awareness of airbus alternate law parameters would have helped greatly.
2. It's very poor design on airbus' part to not provide feedback to the other pilot's stick when one pilot does something. Had the other copilot been aware that his colleague had been pulling back on the stick the whole time, leading to the plane being stalled as it descended through 20,000+ feet (2 whole minutes), he would have definitely corrected the situation. I hate video games for this reason...even the force feedback sticks seem to be fairly useless. Perhaps two sets of controls on each side, one hydraulic, one electro-actuated, so you can reference one with the other and again warn the pilots if they don't reconcile.

Terrible tragedy, and I am tempted to lay a lot of the blame on the video game nature of the controls, as well as the lack of training about alternate law parameters.

[just me]

Tiggsy said:

Is the question above more like "did the plane not feel like it was crashing" - I wondered what the onboard sensation would be to fall that fast or would they not notice? In my mind all the passengers are stuck to the ceiling like a cartoon lift but i suppose its not like that!

Whether you are travelling forward in a train at 200mph, or sitting still, you fell the same downward pull of gravity. You can't tell the difference, except when you are accelerating.

In this case, the plane was in turbulence, disorienting everyone. The engines were not throttled back. The plane's nose was slowly pitched up to the max (I think it was 18º) and the plane's forward motion slowly changed to forward and downward. Doubt any passenger would have noticed, and if they had, they would have assumed that it was necessary for the conditions. The pilots seem to have been far too busy to notice.

[Ian Lancs]

just me said:

2. It's very poor design on airbus' part to not provide feedback to the other pilot's stick when one pilot does something. Had the other copilot been aware that his colleague had been pulling back on the stick the whole time, leading to the plane being stalled as it descended through 20,000+ feet (2 whole minutes), he would have definitely corrected the situation. I hate video games for this reason...even the force feedback sticks seem to be fairly useless. Perhaps two sets of controls on each side, one hydraulic, one electro-actuated, so you can reference one with the other and again warn the pilots if they don't reconcile.

Terrible tragedy, and I am tempted to lay a lot of the blame on the video game nature of the controls, as well as the lack of training about alternate law parameters.

The feedback hasn't been that big an issue on the other few thousand Airbus sold?
WRT the bold bit - aren't pilots still trained to "aviate, communicate, navigate"? The only one of these the crew managed was navigate....

[theboss]

just me said:

Tiggsy said:

Is the question above more like "did the plane not feel like it was crashing" - I wondered what the onboard sensation would be to fall that fast or would they not notice? In my mind all the passengers are stuck to the ceiling like a cartoon lift but i suppose its not like that!

Whether you are travelling forward in a train at 200mph, or sitting still, you fell the same downward pull of gravity. You can't tell the difference, except when you are accelerating.

In this case, the plane was in turbulence, disorienting everyone. The engines were not throttled back. The plane's nose was slowly pitched up to the max (I think it was 18º) and the plane's forward motion slowly changed to forward and downward. Doubt any passenger would have noticed, and if they had, they would have assumed that it was necessary for the conditions. The pilots seem to have been far too busy to notice.

This is my point - they had a huge downward velocity but seem not to have noticed it at any point until the very final seconds of the flight. They simply don't seem to acknowledge altitude other than when the plane initially climbed. It then dropped nearly 20,000 feet and even then when 10,000ft was acknowledged it didn't seem to instill any sort of realisation that, at that rate, they had about 1 minute left until certain death. I realise this is only one of many readings but surely they should have paid some attention to it?

Would anyone care to speculate how much time and/or altitude they would have required to gain speed and restore controlled flight? i.e. at what point were they doomed? I'm just conscious of the fact that by the time they were at 10,000 they may have only had literally a few seconds to do something, or it may have been too late even then.

[Mojocvh]

just me said:

Chilling. I am a private pilot and I am terrified of the sink rate when I don't watch my airspeed on approach. It's what I pay attention to the most. When you are that low to the ground, you can't point the nose down to gain airspeed, and increasing power can not generate lift if it does not change the angle of attack and therefore the speed of airflow past the wings. Quite a few airplanes have crashed because they settled back to the ground under full power.

I wonder if commercial airliners can get tracking/telemetry from satellites and display that as an alternate set of reference data for pilots. If this data indicates something that does not reconcile with the plane's own measuring systems, it would indicated a potentially deadly trim situation.

1. Awareness of airbus alternate law parameters would have helped greatly.
2. It's very poor design on airbus' part to not provide feedback to the other pilot's stick when one pilot does something. Had the other copilot been aware that his colleague had been pulling back on the stick the whole time, leading to the plane being stalled as it descended through 20,000+ feet (2 whole minutes), he would have definitely corrected the situation. I hate video games for this reason...even the force feedback sticks seem to be fairly useless. Perhaps two sets of controls on each side, one hydraulic, one electro-actuated, so you can reference one with the other and again warn the pilots if they don't reconcile.

Terrible tragedy, and I am tempted to lay a lot of the blame on the video game nature of the controls, as well as the lack of training about alternate law parameters.

"so you can reference one with the other and again warn the pilots if they don't reconcile."

how on earth do you engineer such a system? Oh it does it already by FBW!

[Apache]

Ian Lancs said:

The feedback hasn't been that big an issue on the other few thousand Airbus sold?
WRT the bold bit - aren't pilots still trained to "aviate, communicate, navigate"? The only one of these the crew managed was navigate....

How many others have been in that situation though? I agree with just me that the basic mechanical connection between the controls should be maintained, it's an aid to basic communication

[just me]

Mojocvh said:

"so you can reference one with the other and again warn the pilots if they don't reconcile."

how on earth do you engineer such a system? Oh it does it already by FBW!

It CAN do it in FBW. It didn't, in the case of this airbus model. One pilot had his joystick pulled all the way back. The other one had no clue. The computer averaged the two inputs.

Edited by just me on Tuesday 1st May 18:03

[just me]

Popular Science article said:

Unlike the control yokes of a Boeing jetliner, the side sticks on an Airbus are "asynchronous"—that is, they move independently. "If the person in the right seat is pulling back on the joystick, the person in the left seat doesn't feel it," says Dr. David Esser, a professor of aeronautical science at Embry-Riddle Aeronautical University. "Their stick doesn't move just because the other one does, unlike the old-fashioned mechanical systems like you find in small planes, where if you turn one, the [other] one turns the same way." Robert has no idea that, despite their conversation about descending, Bonin has continued to pull back on the side stick.

[just me]

Popular Science article said:

As the plane approaches 10,000 feet, Robert tries to take back the controls, and pushes forward on the stick, but the plane is in "dual input" mode, and so the system averages his inputs with those of Bonin, who continues to pull back. The nose remains high.

Read more: Air France 447 Flight-Data Recorder Transcript - What Really Happened Aboard Air France 447 - Popular Mechanics

So, no feedback, and a watering down of control inputs during critical periods.

[just me]

theboss said:

Would anyone care to speculate how much time and/or altitude they would have required to gain speed and restore controlled flight? i.e. at what point were they doomed? I'm just conscious of the fact that by the time they were at 10,000 they may have only had literally a few seconds to do something, or it may have been too late even then.

Well, it depends on their
1. rate of descent
2. rate of change of descent and whether that's sufficient to keep them above the ground at the lowest point of their trajectory.

So, assuming they put in max correction, what is the minimum amount of time needed to level off from a descent rate of 10,000 ft/min with their trim configuration. I don't know the answer but once this is known we can figure it out. I think one minute would have been sufficient, though. But I don't know. I will ask my pilot buddies.

[Tiggsy]

So would the passengers have just thought it was a bit bumpy until they got a glimpse of the waves?

[davepoth]

Tiggsy said:

So would the passengers have just thought it was a bit bumpy until they got a glimpse of the waves?

At 10,000 ft/min they probably wouldn't have seen the waves.

[tank slapper]

just me said:

One pilot had his joystick pulled all the way back. The other one had no clue. The computer averaged the two inputs.

That is the thing that has puzzled me slightly. It seems an odd way to do things - It allows both pilots to use different inputs, but when they conflict the aircraft doesn't do what either pilot is requesting but something different to both. There may be good reasoning behind it, but I can't see what it is. At the least I would have thought there should be some kind of indicator, verbal or visual, that the control system is receiving conflicting requests.

[croyde]

A BA plane had a fatal accident in the mid 70s and then the deadly Manchester fire in 1985 and then a couple of years ago the 777 that plonked itself down just short of the runway with a couple of injuries.

Are BA lucky or do they have the best pilots and maintenance? I know people complain about the service but I'm far happier on a BA plane than any other.

[mrloudly]

Why was there no "Sink Rate" warning? Shirley that would have given them an idea? Sadly I would imagine at a descent rate of 10,000/min the cabin pressure would have been all over the place?
IMHO there should be an "Automatic recovery" system that engages when the aircraft fly's outside of set parameters. You have to say that there's a definable point at which onboard systems should say
"I have control". I have had a Pitot freeze up on me in IMC in a Robin 400 G-BAMU, it scared the living daylights out of me! The worse thing was, after I switched the heater on (oops), the airspeed reading fluctuated wildly
for about five minutes. I had no option but to rely on the fact that in straight and level flight, at a set RPM, I knew the speed would be OK. At night with autopilots tripping and alarms sounding it must have been horrendous!
By the way, you only forget the pitot heat once when entering cloud ;-)

[just me]

That's a pretty good idea, and with GPS, pretty easy to implement. I wonder why they haven't done so.

Once the FMS has been programmed with the route, unless TCAS indicates otherwise, or other abnormal conditions are detected/dictated, the computer should not allow the aircraft to be flown into dangerous proximity to terrain/water without a LOT of overrides.

Is there even an indicator when normal law has been replaced by alternate law?

Is there an indicator when the two control sticks are being given conflicting inputs?

[Mojocvh]

just me said:

Mojocvh said:

"so you can reference one with the other and again warn the pilots if they don't reconcile."

how on earth do you engineer such a system? Oh it does it already by FBW!

It CAN do it in FBW. It didn't, in the case of this airbus model. One pilot had his joystick pulled all the way back. The other one had no clue. The computer averaged the two inputs.

Edited by just me on Tuesday 1st May 18:03

"One pilot had his joystick pulled all the way back. The other one had no clue. The computer averaged the two inputs."

Nice amalgamation of various events during the time line of the accident, but a TOTALLY FALSE summation of post upset control inputs, 0/10 for the flaming btw

[Chuck328]

just me said:

Is there even an indicator when normal law has been replaced by alternate law?

Yep.

Is there an indicator when the two control sticks are being given conflicting inputs?

Yep. (Although I don't think there had been much, if any inputs from the right hand seat)

[davepoth]

mrloudly said:

I had no option but to rely on the fact that in straight and level flight, at a set RPM, I knew the speed would be OK.

That's the scary thing. if the two pilots had left all the controls alone, it's quite likely that they wouldn't have crashed since the plane was trimmed for level flight.

[Ian Lancs]

Chuck328 said:

just me said:

Is there even an indicator when normal law has been replaced by alternate law?

Yep.

Is there an indicator when the two control sticks are being given conflicting inputs?

Yep. (Although I don't think there had been much, if any inputs from the right hand seat)

There were far too many control inputs from the right seat. Left seat didn't take over until about 90s after the incident started.