Air France flight crash

[SuperBuickGuy]

I have no doubt that they were confused by the loss of airspeed indication, but for an otherwise perfectly serviceable aircraft to be lost due to the failure of one sensor is just hard for me to understand. Surely if you keep the attitude of the aircraft level, keep the throttles where they were, and don't do anything, it will continue to fly. If you pull the nose up, and it starts to fall out of the sky at 10,000 fpm, you're doing something wrong, so try something else, but don't pull the engines back to idle, because that won't help the aircraft stay in the air. How can three supposedly professional pilots be that incompetent? It hardly inspires a lot of confidence in the state of pilot training, or in Airbus.

pilot had 11,500 hours, co-pilot had 6500 hours, other co-pilot had 2700 hours.... and I'm sticking with Airbus building a faulty plane

[TheSilverBuick]

I'm still of the opinion that they lost the speed sensor and the pilots believed they were going faster than they actually were. And if the other forum post is right, they switched to the mode that let them override the safety limits. What's 11,000 hours translate to in years for commercial pilots? Because from knowing equipment operators, that sure doesn't sound like a lot, 5.5 years at a 40 hours per week, and that's the senior guy. So seven years in the actual seat?

According to google, average is around 75hr/month. So the senior pilot probably had around 12 years, which is a fair amount though he was not in the cabin until essentially the end. The least experienced guy would be ~3 years. Still doesn't sound like much to me.

[BangShift McT]

11,000 is a healthy amount. By comparison, Capt. Sullenberger (the one who flew the A320 into the Hudson River a couple of years ago) was pushing 19,000 and was close to the end of his career anyways. Also have to understand that there is more to pilotage than just seat time. Experience with weather charts, flight performance charts, and keeping up with at least the avionic changes in the model aircraft you rate in are up there too.

[Caveman Tony]

I'm gonna go with software failure.

We had a C-17 do some funky 'porpoising' along the runway at about 50-100 feet above ground, 160-180 kts.

Turns out the pilot (short guy) had the seat all the way up: he was pulling back on the controls trying to gain altitude, but the stick was up against the seat.... the software thought there was a flight control jam and was causing the system to have a fit. Flight controls were cycling up & down rapidly.

pretty f'n scary when you're trying to land the damn thing, all because of software that hadn't been programmed to encounter an issue like that.

[oldsman496]

I'm really torn on this one... I can't see how those pilots weren't pulled up against the seat belts at that descent rate. ummmmm....... ya know you're fallin' when that happens, black sky or not.

[TheSilverBuick]

If I'm not mistaken, once there rate of decent levelled out, even at 120mph vertically, then gravity would resume and feel normal because they were not accelerating. Similar to why you don't feel constantly pushed back in your seat in your car while cruising, only the vector is in a different direction. So they felt a brief sensation of falling, accelerating to 11,000ft/min, then once at terminal velocity at 11,000ft/min vertically gravity takes back over. So short of looking at the altimeter, they wouldn't likely know they were falling, and if they didn't believe the gauge....


***

http://en.wikipedia.org/wiki/Free_fall

The drag forces in such situations prevent them from producing full weightlessness, and thus a skydiver's "free fall" after reaching terminal velocity produces the sensation of the body's weight being supported on a cushion of air.

Or in the pilots case, sitting in their seats.

[SuperBuickGuy]

If I'm not mistaken, once there rate of decent levelled out, even at 120mph vertically, then gravity would resume and feel normal because they were not accelerating. Similar to why you don't feel constantly pushed back in your seat in your car while cruising, only the vector is in a different direction. So they felt a brief sensation of falling, accelerating to 11,000ft/min, then once at terminal velocity at 11,000ft/min vertically gravity takes back over. So short of looking at the altimeter, they wouldn't likely know they were falling, and if they didn't believe the gauge....


***

http://en.wikipedia.org/wiki/Free_fall

Or in the pilots case, sitting in their seats.

I thought terminal velocity was 16 ft/sec... in any case, terminal velocity means the highest rate you can fall in the atmosphere, and I am relatively sure 11,000 feet a minute is well beyond that rate (that said, maybe I'm not moving the decimal.... where's CTX?)

interesting... I just did the math - terminal velocity is also said to be 125 mph... if you do the math that plane was literally falling at 125.47 mph.... which should have been more than enough to generate lift

[BangShift McT]

The speed is good, but the second part of making lift is making sure you have a decent angle-of-attack with the wings in order to create that lift. If your angle is too steep you don't make lift at all...which backs the theory the nose was extremely high. You can make it with the nose down, but nose high and falling won't do anything for the plane.

[TheSilverBuick]

I'm still standing by the pilots didn't know they were falling or stalled because they didn't believe the instrument readings, rather the instruments were reading right or wrong.







^^^It's still annoying that quote's don't nest more than one layer. My quote of the article is completely missing from Stoneshrink's post.

[SuperBuickGuy]

The speed is good, but the second part of making lift is making sure you have a decent angle-of-attack with the wings in order to create that lift. If your angle is too steep you don't make lift at all...which backs the theory the nose was extremely high. You can make it with the nose down, but nose high and falling won't do anything for the plane.

I understand what you're saying, but they would have been falling backwards at 125 mph - you'd think it'd flutter a bit if that were true.... this seems more like the plane simply fell out of the sky in complete defiance of most of the physical laws we hold most dear.

[SuperBuickGuy]

I'm still standing by the pilots didn't know they were falling or stalled because they didn't believe the instrument readings, rather the instruments were reading right or wrong.







^^^It's still annoying that quote's don't nest more than one layer. My quote of the article is completely missing from Stoneshrink's post.

I concur.... I wish we could more easily nest posts and that we could use emoticons without "go advanced"

[dieselgeek]

I understand what you're saying, but they would have been falling backwards at 125 mph - you'd think it'd flutter a bit if that were true.... this seems more like the plane simply fell out of the sky in complete defiance of most of the physical laws we hold most dear.

it's widely known in avation circles that it's not a good idea to fly a plane into a storm. Considering there were storms present and dead ahead of them, and knowing what happens when you fly an airliner into a downdraft already, it's probably going to be pretty hard to blame all of this entirely on Evil Computer Control Systems with any credibility.

I'm also not so sure it's a good idea to gripe about computer controls in general, even if it was 100% a software or computer hardware problem, the computer controlled aircraft have moved more passengers safely per mile than the old school manual controls.

Meanwhile, I used to make fun of Airbus and joked about them being crappy until I saw that one of them made a water landing without ripping it's wings off. Other airliners have tried the same and usually end up tearing the wings from the fuselage and rolling dangerously... airbus must not build too bad of a plane if a captain can land one safely (and comfortably) on water.

[TheSilverBuick]

this seems more like the plane simply fell out of the sky in complete defiance of most of the physical laws we hold most dear.

The laws of physics surprisingly aren't as intuitive as they often seem, and what seems improbable in a lot of cases is usually explained by counter-intuitive physics. I learned plenty of that in a year of physic's, I couldn't believe how often my gut feeling on how something would work or turn out was simply wrong.

Also remember, their flaps weren't down, so their stall speed is pretty dang high, they still had forward momentum, but likely well under their stall speed.

[SuperBuickGuy]

it's widely known in avation circles that it's not a good idea to fly a plane into a storm. Considering there were storms present and dead ahead of them, and knowing what happens when you fly an airliner into a downdraft already, it's probably going to be pretty hard to blame all of this entirely on Evil Computer Control Systems with any credibility.

I'm also not so sure it's a good idea to gripe about computer controls in general, even if it was 100% a software or computer hardware problem, the computer controlled aircraft have moved more passengers safely per mile than the old school manual controls.

Meanwhile, I used to make fun of Airbus and joked about them being crappy until I saw that one of them made a water landing without ripping it's wings off. Other airliners have tried the same and usually end up tearing the wings from the fuselage and rolling dangerously... airbus must not build too bad of a plane if a captain can land one safely (and comfortably) on water.

I agree - it is amazing that it didn't take the wings off, miraculous even, despite ripping the engines off.... however, let's not forget that a 747 literally blew the tail off an Airbus just after 9/11.


this flight is most (ummm what word) frightening? because it happened 1) when airplanes almost never crash; 2) these people had to know they were going down; 3) it almost seems some twilight zone physics were involved; and 4) there was apparently nothing anyone could do about it....

[Silver68RT]

I don't see anything twilight zone going on, and there was no reason the plane had to crash if the pilots had taken the appropriate actions. They pulled it up into a stall, and kept it stalled until it smashed into the ocean. There were apparently 3 stall warnings that they did not acknowledge verbally. The only thing that makes sense is that for some reason they became disoriented, and thought that they were diving nose first at 11,000 fpm, and kept trying to pull up for that reason. Surely the instruments would clearly indicate that they were nose up instead of nose down though, which is what I don't get. If they'd put the nose down, picked up some speed and reduced the angle of attack to something where the airplane could generate lift again, I see no reason they couldn't have saved it.

I'd be very interested to see Captain Sullenberger's take on the actions of the crew. Apparently he trains pilots how to respond to emergency situations. I'd think his military background probably helped a lot in the Hudson River case, I wonder if any of the Air France pilots had any military history.