Flight 447 'Black Box' Decoded

The Washington Post ^ | 05/27/2011 | Sarah Anne Hughes

[Greysard]

"Black box recordings from Air France Flight 447, which crashed into the Atlantic Ocean two years ago, revealed new details about the plane’s final moments. But the report did not assign blame or give an explanation for the crash, which killed all 228 people aboard."

[UCANSEE2]

The crew included two co-pilots and one captain. Both chairs were occupied by co-pilots; the captain, when he awoke and came to the cockpit, just stood behind them, as I understand.

Thank you for that information.

Now I know more, yet understand less. Funny how that works sometimes.

[AlexW]

“He thinks that the plane was going slower than what they thought”
________________________________________

I am would think the plane had at least two pito tubes, which are heated to prevent ice.
If ice blocked them, it should indicate a slower then actual speed.
Someone can correct me if I am wrong.

[murrie]

Thanks UCANSEE2. My hubby is sitting here with me... I was dictating his conversation. I’m always a little suspicious of these “final assessments on how and why planes crash. They always seem to blame the pilot. And the pilot is dead-no way to get his perspective on the situation. Just a little to convenient it seems like.....

[murrie]

Hey Alex-my hubby said the plane had 3 pito tubes. Hmm. He jokingly said they were prolly all made by the same manufacturer and that it was prolly “a French thing”. Sorry. Bad humor.....

[wideminded]

from what I read it appears that the co-pilots of the AF447 failed to recognize the stall

I'm not a pilot either, but you would think that one of the pilots would have noticed the altimeter rapidly decreasing. That coupled with the fact that the stall warning had already sounded should have given them a clue.

Final vertical speed = -10912 ft/min = -124 MPH. Perhaps some of the passengers could have been alive for a while.

[raygun]

Black box of doomed Rio-Paris Air France flight recovered, say investigators

Air France crash victims 'must not be recovered'

Flight AF 447 on 1st June 2009 - 16 May 2011 briefing

Air France jet crashed nose-up after 4 minute ordeal

[boop]

I can’t imagine the horror of falling from 38,000 ft in the sky into the ocean all in 3 minutes 30 seconds.

[UCANSEE2]

I’m sure a 747 with cement a foot thick would not fly, but I do believe you could make a plane out of cement, and it could fly.

Not that I would want to be the test pilot.

[Greysard]

I am would think the plane had at least two pitot tubes, which are heated to prevent ice.

FAA requires heated pitot tubes:

On 3 September 2009, the American FAA issued a final Airworthiness Directive, which requires the pitot probes manufactured by Thales Avionics, which were installed on the A330 and A340 aircraft, to be replaced with heated pitot tubes manufactured by Goodrich Sensors.

However Airbus installed non-heated pitot tubes from day one; this led to a bunch of problems just like this one, only in those cases the pilots managed to recover. This time they didn't.

Airbus "recommended" to upgrade the pitot tubes, but this was not a requirement. Air France decided to sit on this:

On 6 June 2009, Arslanian [the head of the BEA] said that Air France had not replaced pitot probes as Airbus recommended on F-GZCP, saying that "it does not mean that without replacing the probes that the A330 was dangerous."

The AF447 had the non-heated sensors, all three of which probably froze solid in seconds. The auto{everything} instantly failed, and pilots were forced to take control.

[driftdiver]

humans can easily survive 36gs. many were probably killed by injuries caused by parts of the plane and the rest by drowning.

[AlexW]

“The stall warning system malfunctioned because of wrong airspeed.”
______________________________

Well, I have no clue as to the stall warning system on a
commercial jet, but in my first plane, it was just a simple little movable flap of metal on the wing.
It connected to a switch that would sound the stall alarm.
Of course, if it iced over, it would fail to do anything.
It had no heater to prevent icing, but in my case, if icing was that bad, the plane would crash anyway.

I practiced many controlled stalls, and the recovery was just to let the stick go.

Could the Air France jet have gone into a flat spin?
I understand that they are not recoverable.

[murrie]

But their airspeed indicator was telling them that they were going to fast. My hubby thinks that when the autopilot kicked off the plane was beginning to enter a stall, with an “aft CG” situation-the plane stalled and then the plane entered a spin. Large T-CAT aircraft are not designed nor tested for recovery from spins. My hubby thinks that prolly by the time they noticed the altimeter “unwinding” they were already into a spin and outa control. Ok. Enough aerodynamics for one evening....

[skr]

Dead pilots have no need to feel good about themselves.

[murrie]

The auto{everything} instantly failed, and pilots were forced to take control.

Sad- trying to take control at the last minute when everything is already out of control......

[raygun]

The FO in this incident had piloted that route 39 times to the captain's 16. However, the captain had twice as many hours experience as the FO (who was most likely captain qualified in his own right but served as FO on this particular flight). The second officer while not inexperiencee, had 1/2 the experience of the FO.

They had about 20,000 hours of cumulative flight time between the three of them.

Its unknown who pilot flying (PF) was and pilot monitoring (PM), but my guess is 2nd officer was PF (as the captain was on break at the time). My guess is that the FO was logging acting-PIC hours, and the 2nd officer was logging acting-FO hours.

That's not how it works out all the time (captains discretion). Also, there's a difference between FO hours and PF houirs (they might not be the same). If FO is PF, then captain (if flying) would be pilot monitoring (PM) - and does all the grunt work that the FO normally does.

[AlexW]

“Airbus installed non-heated pitot tubes from day one;”
_________________________________________

Good grief...How in the world could they not have heated pitots?
Even the simplest airplanes have heated pitots.
One would think that would be as basic as having wings.

[Greysard]

I practiced many controlled stalls, and the recovery was just to let the stick go.

There is no stick on Airbus A330, only joysticks:

I have no idea what happens if you disengage the autopilot (already happened in that thunderstorm) and don't touch the joystick. Probably nothing good, considering weather.

I read that at high altitude and speed the A330 is very sensitive to everything, and it is trivial to stall it. Basically you have to have a computer to fly the thing safely because the margin for error is so small.

The stall alert system is also part of the software that flies the aircraft. Nobody can tell what it did; I'm sure the investigation will feed intentionally wrong data into A330's avionics to see what it does. If there is a bug it better be found.