[raygun]

BEA released preliminary interim findings today:

Summary of the new findings based on recovered FDR/CFR:

At this stage of the investigation, as an addition to the BEA interim reports of 2 July and 17 December 2009, the following new facts have been established:

• The composition of the crew was in accordance with the operator’s procedures..
• At the time of the event, the weight and balance of the airplane were within the operational limits..
• At the time of the event, the two co-pilots were seated in the cockpit and the Captain was resting. The latter returned to the cockpit about 1 min 30 after the disengagement of the autopilot..
• There was an inconsistency between the speeds displayed on the left side and the integrated standby instrument system (ISIS). This lasted for less than one minute.

After the autopilot disengagement:

• the airplane climbed to 38,000 ft.
• the stall warning was triggered and the airplane stalled.
• the inputs made by the PF were mainly nose-up.
• the descent lasted 3 min 30, during which the airplane remained stalled. The angle of attack increased and remained above 35 degrees.
• the engines were operating and always responded to crew commands.

The last recorded values were a pitch attitude of 16.2 degrees nose-up, a roll angle of 5.3 degrees left and a vertical speed of -10,912 ft/min.

Accident to the Airbus A330-203
flight AF 447 on 1st June 2009
Update on Investigation

(1219 KB PDF)

[Moose4]

This is starting to sound eerily like Aeroperu 603 or Birgenair 301...pitot-static system problems leading to inconsistent instrument readings, causing the pilots to take inappropriate action based on the faulty instrument readings. Technically it’s still considered “pilot error” but when getting bombarded with conflicting, or even impossible, instrument readings, it’s bloody hard to figure out what the correct action to take might be.

}:-)4

[B4Ranch]

While I was reading your post I kept hearing, “Drop the nose and increase airspeed. Maintain level flight. You can figure out the problem when you regain control.” I don’t know how many times I heard that in my earphones when I was earning my license. Every instructor repeated it and repeated it.

[Yo-Yo]

The aircrew were not thoroughly trained in what to do when one or more pitot tubes are iced over, and the flight computer switches over to alternate law.

You get spoiled with an aircraft that under normal circumstances will not allow you to stall the aircraft. In Alternate Law mode, the aircraft blindly follows the pilot's inputs regardless of the aircraft's flight envelope.

After AF 447, pilots have been intensely trained on how to identify and fly through pitot tube icing and loss of reliable airspeed data.

AF447 stalled but crew maintained nose-up attitude

By David Kaminski-Morrow

French investigators have disclosed that the crew of Air France flight AF447 maintained nose-up inputs to the aircraft even after the Airbus A330 entered a stall.

The inquiry has also revealed that the pilots set engine thrust variously to go-around power and idle as they battled to rescue the jet.

In an update to the loss of the A330 over the South Atlantic two years ago the Bureau d'Enquetes et d'Analyses has detailed the last few minutes of the flight. BEA said the aircraft climbed from its cruise altitude of 35,000ft towards 38,000ft and stalled, but added that the flying pilot "maintained nose-up inputs" to the controls.

BEA confirms that the captain had left the cockpit to rest, about eight minutes before the emergency on 1 June 2009, having discussed with the relief crew possible turbulence ahead of the aircraft.

The pilots altered course slightly, about 12° to the left, and as turbulence increased they opted to reduce speed to Mach 0.8.

About 2min later the aircraft's autopilot and autothrust disengaged, and remained so for the rest of the flight. This would have put the jet into 'alternate' law, meaning it lost its angle-of-attack protection.

The aircraft began to roll to the right, and as the pilot made a nose-up left input, the A330's stall warning sounded twice - an indication that the aircraft had exceeded a critical angle-of-attack threshold.

The primary flight display on the captain's side showed a "sharp fall" in speed from 275kt to 60kt, and the aircraft's angle of attack "increased progressively" beyond 10°.

While the jet had initially been cruising at 35,000ft, investigators stated that the aircraft climbed, with a vertical speed of 7,000ft/min, heading towards 38,000ft.

The pilot made nose-down inputs as well as inputs for left and right roll. The vertical speed fell back to 700ft/min, the displayed speed "increased sharply" to 215kt, and the angle of attack reduced to 4°.

In its update the BEA said the non-flying pilot "tried several times to call the captain back".

There was another stall warning and the BEA said the stall warning sounded again. The thrust levers were positioned for take-off/go-around power but the flying pilot "maintained nose-up inputs".

Angle of attack continued to increase, it added, and the trimmable horizontal stabiliser increased from a 3° nose-up position to 13° nose-up - where it stayed for the rest of the flight.

The aircraft reached 38,000ft - its maximum altitude - with its angle of attack having increased to 16°.

AF447's captain returned to the cockpit - just 90s after the autopilot had disengaged - by which time the aircraft had started its fatal descent.

As it passed through 35,000ft the angle of attack increased to more than 40° and the A330 was descending at 10,000ft/min. Its pitch did not exceed 15°, its engine power was close to 100% of N1, and the jet oscillated with rolls of up to 40°.

"The [flying pilot] made an input on the sidestick to the left and nose-up stops, which lasted about 30s," said the BEA.

Just 20s after the captain returned to the cockpit, said the BEA, the thrust levers were set to the 'idle' position, with the engines delivering 55% of N1.

Measured angle of attack values, the BEA pointed out, are only considered valid when the measured speed is above 60kt. It said that the angle of attack, when valid, always remained above 35°.

AF447's had turned almost a three-quarter circle to the right during the emergency, and - having descended for 3min 30s - it struck the ocean surface with a ground speed of just 107kt, a nose-up pitch attitude of 16.2°, with a heading of 270°.

BEA stated that the aircraft stalled but that the inputs from the flying pilot were "mainly nose-up". It added that the engines "were operating and always responded to crew commands".

[MindBender26]

It’s the unfortunate (and unforgiving) classic:

1: Stall
2: Spin
3: Crash
4: Burn
5: Die

[spodefly]

So they stalled at FL38, and just rode the stall all the way down? Very bizarre.