EASA has just called a Loss of Control (LOC) conference in
Definitely better late than never. The Air France 447 accident suggests that no airline can consider itself free of the risk of loss of control if circumstances combine to confuse their pilots.
Meanwhile the French investigator (BEA) of the AF447 crash has shed new light on flight deck activity by publishing a transcript of flight deck conversation during the last few minutes. Tomorrow it will publish an English translation, but here is my understanding of it until they do.
The fact that AF447 crashed following a transient airspeed reading anomaly in an otherwise healthy aeroplane has always appeared to suggest the pilots failed to comprehend fully - and therefore to control - what was going on. The transcript reveals their total bewilderment about what was happening following autopilot/autothrottle disconnect.
When the captain departed the flight deck for his rest period, he did not give instructions as to the roles of the two copilots, according to the BEA. The copilot who remained in the right hand seat (RHS) took the role of pilot flying (PF) without actually making it explicit. The BEA notes that this lack of clarity about the roles of PF and pilot not flying (PNF) under these circumstances is unacceptable.
In the cruise, however, the PF was adjusting his weather radar range to identify storm clouds they would need to avoid, and discussing anti-icing precautions to apply in their vicinity. These are standard preoccupations for pilots in the inter-tropical convergence zone, and the action the pilots were taking shows they were awake despite the fact things were quiet and the time was 02:00h.
Then the speed sensor disparity, triggered by ice crystals in the pitot tubes, caused the autopilot/autothrottle to disconnect, and the calm was shattered. The control system shifted into alternate law, in which the aircraft loses its stall protection (but not stall warning). The PF said: "I have the controls."
The PF's initial reaction was to pull the stick back, putting the aircraft into a climb. Five seconds later there was a system-generated verbal warning of "stall, stall". The PF reacted with "What's that?" and the PNF replied "Stall". The PF's response was: "We haven't got a good...not a good...speed reading."
Moments later the PNF said: "We have lost the, the, the speeds then, autothrust engine lever thrust".
Meanwhile the aircraft was still climbing, the PF's stick still held back, the speed well below stalling speed, the throttles in the Climb detent, and power increasing to 100%.
The PNF then says: "We are losing...Wing anti-ice." He switched the anti-ice on, and two seconds later exclaimed - twice: "Pay attention to your speed", to which the PF replied: "Okay okay okay I will descend again," but in the next 15s or so the two pilots exchanged words indicating confusion about whether they were still climbing or had achieved descent.
But the aircraft was still, indeed, climbing, and the PF, despite temporarily relaxing the stick-back input, had resumed it.
Some 25s elapsed between the PNF warning the PF to "watch his speed" and the time that the aircraft starts to descend. But when it does, the aircraft's attitude is still between 6deg and 13deg nose-up, and at that vertical-speed reversal point the "stall, stall" warning returns, this time with the "cricket" sound as well. Five seconds later the crew moves the throttle levers from the Climb detent into TOGA (take-off/go-around) position to obtain full power.
No words are spoken by either of them for about 10s, the descent rate is increasing, and then the PNF says: "Above all avoid applying lateral [roll] control", to which the PF replies: "I'm in TOGA, eh?" and 18s later the PNF says: "We have the power, so what's going on?"
Nobody has mentioned the aircraft attitude so far. In fact no-one ever mentions it in a substantive way. The attitude is actually about 18deg nose up, which is the reason the engine power is not producing the results the crew expect to see. Vertical speed (descent) is still increasing dramatically, and the speed the pilots see is varying between 130kt and 160kt.
The PF says: "I don't have control of the aeroplane here. I have absolutely no control of the aeroplane." His stick input is on the nose-up and full-left stops. The attitude is nearly 15deg nose up and the roll angle is varying between 16deg right and 40deg right.
The PNF says: "Control to the left", and he takes control. He puts the stick fully left, then nearly full nose up. The Nos 1 and 2 angle of attack sensors have entered the "invalid" range, and the No 3 reads 33deg. The PF says: "I have the impression of high speed."
Probably slipstream noise.
At that moment the captain re-enters the flightdeck, and says: "What are you doing. What's going on? I don't know I don't know what's going on."
The stall warning sounds again, with the cricket sound.
The power levers are placed in the idle detent. The vertical speed is increasing through 14,800ft/min.
The airbrakes are deployed.
For the remainder of the descent to impact with the sea, the verbal exchanges continued to indicate that none of the three pilots on the flight deck could understand what was going on sufficiently well to take effective recovery action. They appeared to be experimenting with different control positions, including introducing rudder inputs, but none of the pitch inputs to the sticks were nose-down except momentarily.
When the impact came, the sidestick on the left side had a nose-down and right-roll input, the right hand sidestick was on the nose-up stop with neutral roll input.
on August 3, 2011 1:11 AM | Reply
If you are stalled put the nose down. If the ASI is inoperative put the airplane into a specific attitude and set the throttle as defined in the checklist. It's literally that simple.
It'll be interesting to read the final report but this seems to be shaping up to be a tragic case of confirmation bias where, for some reason, the pilots thought they were in danger of overspeed and ignored all other inputs that said the opposite.
on August 4, 2011 8:18 AM | Reply
http://thehangar.tv/profiles/blogs/when-is-an-hour-not-and-hour
on August 4, 2011 6:10 PM | Reply
There was this A330 upset-mishap on1Jun09.
And now there is an INVESTIGATION by the French BEA, probing an Air France company airliner, mishap-aircraft manufactured by AirBus. The INVESTIGATION holds some interesting contrasts to the NTSB's probe of the mysterious Boeing 727 CRZ-upset at 39000 feet, on 4Apr79.
This AF447 case now is less mysterious. BEA seems much more focused on the direct evidence (avoiding erroneous assumptions), but still there are the same conflicts between the pilots' association and the investigating-authority.
Maybe CBS will re-broadcast its TV-documentary:
_The Plane That Fell From the Sky_
shown 10pm 14July1983.
That CBS documentary should now be UPDATED:
-- contrasting the AF447 upset-to-impact, against the TWA841 / 4Apr79 Yaw x Roll = DIVE! upset;
-- contrasting those TWA pilots' RECOVERY from an uncontrolled yawing-rolling-DIVE, against the AF447 pilots' response during high-AoA dive [and comparing the similar "back-stick" pilot-response];
-- CBS could expose the investigator-errs committed by the USA's NTSB in their botched investigation of that Boeing 727 upset, contrasted with BEA's investigation of a French manufacturer.
CBS could ask the NTSB "Why does the USA's NTSB refuse to comply with its own rules? Why has the NTSB refused to even consider the "alpa" Petition for Reconsideration against AAR 81-8?"
Flt Int'l, 1Feb95, reviewed that NTSB B727-investigation:
"Saginaw ghost ... A mystery from the past may have relevance for the present...."
Then, commenting on an unusual NTSB revision to an ATR72-accident report, Flt Int'l mentioned the NTSB's unwillingness to address their more gross investigative-errs:
http://www.flightglobal.com/articles/2002/10/01/155591/changing-the-past.html
Flt Int'l, 1Oct2002, "“Changing the past ...
Accident investigation reports are not always the last word ..."
on November 6, 2011 8:20 AM | Reply
If the pilots heard the stall warning and the pitch attitude above 13 deg, why not recover stall by pushing the nose down? at some point a 33 deg nose up position while rapidly gaining vertical speed... with all stall warning indicators going off... applying a roll control only complicates recovery measures. Unless there's more than what's on that transcript, I do believe Pilot Error had quite a lot to play in the accident, though my sincere condolences go to the pilots' families....
on January 6, 2012 1:30 AM | Reply
Even though the only way to break a stall in this case would ve been a significant pitch change to at least 5 degrees down it would be hard for any mortal being to do so with a v/s of nearly 15000 fpm staring at you!Overiding human instincts must kick in at some stage in this horrible scenario.
on August 2, 2012 3:33 AM | Reply
The accident was caused by the co-pilot induced stalled glide condition and remained in that condition until impact. To recover from stall is to set engine to idle to reduce nose up side effect and try full nose down input. If no success roll the aircraft to above 60° bank angle and rudder input to lower the nose in a steep engaged turn. Pilots lack of familiarity and training along with system malfunction contributed to this terrible accident. Also the following contributed to the accident
(1)the absence of proper immediate actions to correct the stalled glide
(2) Insufficient and inappropriate situation awareness disabling the co-pilots and the captain to become aware of what was happening regarding the performance and behaviour of the aircraft
(3)lack of effective communication between the co-pilots and the captain which limited the decision making processes, the ability to choose appropriate alternatives and establish priorities in the actions to counter the stalled glide
During most of its long descent into the Atlantic Ocean, Airbus A330-203 was in a stalled glide. Far from a deep stall, this seems to have been a conventional stall in which the Airbus A330-203 displayed exemplary behavior. The aircraft responded to roll inputs, maintained the commanded pitch attitude, and neither departed nor spun. The only thing the Airbus A330-203 failed to do well was to make clear to its cockpit crew what was going on.Its pitch attitude was about 15 degrees nose up and its flight path was around 25 degrees downward, giving an angle of attack of 35 degrees or more. Its vertical speed was about 100 knots, and its true airspeed was about 250 knots. It remained in this unusual attitude not because it could not recover, but because the co-pilots did not comprehend in darkness, the actual attitude of the aircraft. The co-pilots held the nose up. If the co-pilots had pushed the stick forward, held it there, and manually retrimmed the stabilizer, the airplane would have recovered from the stall and flown normally.
Air France complained that the copilots did not have enough time to analyze the situation. Gravitational stalled glide does not allow timeouts, to thoroughly discuss the situation to find out what went wrong. The co-pilots - 37 year old David Robert and 32 year old Pierre-Cédric Bonin missed the cardinal rule that first they must fly the airplane, and after start analyzing the situation, since a falling airplane is not going to wait for them. If they did not understand the instruments, then instead of pondering on it they should have come to the quick conclusion that they did not understand those instruments, and apply the unreliable airspeed procedure clearly prescribed for that situation, which is a blind, given thrust and pitch setting for the given configuration, and let the airplane fly itself, and only after get to analyzing what went wrong, and by the time they finished, the root-cause (pitot icing) would have probably cured itself. It was the safe solution to the problem, but not applied.
The Airbus A330 performed exactly as it was designed and described when the stall warning cut out at the end of valid values, except the co-pilots did not know it. Unfortunately, it happens too often with catastrophic results that pilots are not familiar with the systems of their own airplane, such as in the case of American Airlines 587 over Queens, which was clearly the airline’s fault.
Air France also argued that the stall warning system in the A330 is too “confusing”. Every modern airplane is quite a confusing piece of machinery. It is full of buttons, levers, all kinds of red, yellow, green lights with buzzers, and a host of other indicators and controls inside, which can look very confusing indeed, but it is the pilot’s duty to reign on them, or not to be pilot.
Airbus A330-203 is a new generation, highly automated piece of equipment with drastically simplified controls, displays, and instrumentation compared to older models. Still, pilots with the same human capabilities as the ones on Air France flight 447 could very well stay in full control in those planes, and many times acted heroically saving situations much graver than where the plight of Air France flight 447 started, such as United Airlines flight UA232 at Sioux City, or Air Canada flight AC143, the Gimli Glider. If those pilots could perform well in those older, much more complicated aircraft in tougher situations, then there is no excuse for the co-pilots of AF flight 447 to be confused in a generally much simpler and easier-to-fly aircraft.
The Airbus A320 is a digital fly-by-wire aircraft as the flight control surfaces are moved by electrical and hydraulic actuators controlled by a digital computer. The computer interprets pilot commands via input from a side-stick, making adjustments on its own to keep the plane stable and on course, which is particularly useful after engine failure by allowing the pilots to concentrate on engine restart and landing planning. Some say the Airbus A330 is a “video-game” airplane due to its side-stick control, which does not match up in real hard situations. But who can say that after the successful ditching of US Airways flight 1549 on the Hudson River? It was an Airbus A320 with the same side-stick control, and it matched up with the hardest situation very well with an experienced 57 year old Captain Chesley Sullenberger at the command. The Airbus A330 is not a video-game airplane, it is the airlines that make it a video-game by cutting corners, taking advantage of its superior automated capabilities thinking that it flies by itself, and no training and no knowledge of even the basics of the principles of flying is required in them for their pilots, as was demonstrated by the co-pilots of flight 447, who seemed to be incapable to react even on a basic level to the phenomenon of the aerodynamic stall. The co-pilots had not applied the unreliable airspeed procedure. The co-pilots apparently did not notice that the plane had reached its maximum permissible altitude. The co-pilots did not read out the available data like vertical velocity, altitude, etc. The stall warning sounded continuously for 54 seconds. The absence of any training, at high altitude, in manual airplane handling and in the procedure for ”Vol avec IAS douteuse” (Flight with questionable Indicated Airspeed) caused this terrible accident. Evidently, it might not be what Airbus had on its mind designing the aircraft. They might have meant the best of the both, an airplane with superior controls, matched with seasoned pilots with superior education in the principles of flying and the handling of hard situations, best of the best, as airlines are prone to boast of their flying personnel, to represent quality improvement in flying safety by this pairing. Now, if this piece of equipment falls in the hands of the airlines who use it as a video game to save training costs, telling only their pilots that “if the red light on the right side blinks, just pull the stick back as hard as you can, and let the system do the rest”, they can get away with it as long as everything is normal, the airplane is good enough for that, but in unforeseeable situations, such as the flight 447 en-route to Paris on that night, without any independent knowledge of flying in general, the video-gaming with the aircraft may ultimately come to a fatal end.
However, beyond the reasoning and explanations there is still some eeriness about the crash, taking in consideration that Air France flight 447's pilots just sat there in daze squeezing the control stick, barely being able to do more than commenting on how the airplane was falling out of the sky until crashing into the Atlantic Ocean, the arrival of the 58-year-old flight captain Marc Dubois in the cockpit not making much a difference either. The question might arise whether weren’t the pilots in a mentally incapacitating state of shock and disbelief? Whether do or can Air France test pilots of how well they can keep their mental stability under the duress of a catastrophic situation? None of it seems to be the fault of the Airbus A330, which needs only good, trained pilots to give superior performance for the good of the flying public. Very similarly 3 decades ago Captain Madan Kukar's mistaken perception of the Air India Flight 855 situation resulted in causing the Boeing 747-237 to rapidly lose altitude and the airplane hit the Arabian Sea at 35 degree nose-down angle.
Practicing recovery from “Loss of Control” situations and improve flight crew training for high altitude stalls (simulator training usually has low altitude stalls which are significantly different due to energy status of the aircraft) should become the mandatory part of recurrent training.
on August 7, 2012 4:23 PM | Reply
BEA published its final report on the accident. I read it and all i could remember was the frase
Lack of basic airmanship skills. http://yosiftrayanov.wordpress.com/2012/08/06/air-france-flight-477/
There you can find graph of the CVR and FDR for the last 4-5 minutes of the flight and also the official report by BEA.