Posted on 05/29/2011 12:42:16 PM PDT by lbryce
HE was one of Air France's "company babies": a dashing 32-year-old junior pilot - and a keen amateur yachtsman - who had been qualified to fly the airline's ultra-sophisticated Airbus A330 jet for barely a year.
Yet despite his inexperience, Pierre-Cedric Bonin found himself responsible for the lives of 228 passengers and crew members on June 1, 2009, when the cockpit of his $190 million aircraft lit up with terrifying and contradictory alarm signals en route from Rio de Janeiro to Paris.
While Bonin held on to the plane's “side-stick” controller and looked at his instruments in disbelief, his co-pilot, David Robert, 37, began troubleshooting. The captain, Marc Dubois, 58, was napping outside the cockpit.
According to a newly-released report by French investigators - which finally answers some of the questions surrounding the mystery of Flight 447 - a fatal sequence of events had already been triggered when the plane's external speed sensors suddenly gave inconsistent readings, possibly because of ice.
This is thought to have caused the autopilot to disengage, which in turn brought warning of an “aerodynamic stall”.
That is when Bonin - who remained at the controls while Robert shouted with increasing desperation for the captain - did something that aviation experts have described as inexplicable: he pointed the nose of the Airbus upwards, causing it to slow down dramatically. He kept doing this for at least one minute until the plane had climbed 3,000ft to 38,000ft.
This one rudimentary mistake, according to the initial findings of France's aviation safety authority, might have been responsible for the aircraft no longer having enough air flow over its wings to remain aloft, although no blame has yet been officially assigned.
(Excerpt) Read more at theaustralian.com.au ...
I can see how that would have saved a lengthy aquatic search, but how would it have saved the airplane? If the instruments were not working for the guys in the cockpit, would have they have been working some controller in Paris?
If your ASI is showing you are at the NTE (not-to-exceed) speed, the last thing you want to do is lower the nose. Losing a wing is much less attractive at altitude than getting into a stall.
The CVR suggested the pilots knew the instruments were giving bad data. Regardless, as soon as one’s intestines lodge in one’s throat, and the checklist is on the ceiling, one knows they are in a stall. Stalls are stalls. They are unsettling. The horn, the burble, the sluggish controls, followed by that (literal) sinking feeling.
To be crude, I recall an Air Force instructor pilot who said the turn and slip indicator (needle and ball) served the same purpose as one’s sphincter. He used a different term, but you get my drift. If your sphincter rises into your chest, your instruments may be lying to you.
Reminds me of the old saying, “If it ain’t Boeing, I ain’t going.”
“You do realize that the average air temperature at 35,000 feet is -50 degrees, don’t you?”
And?
Tens of thousands of aircraft fly at this altitude daily and their pitot tubes don’t freeze. In fact, most commercial passenger aircraft have heated tubes to rule out single point failure including this one.
Air France has given several theories on this crash from a lightning strike to icing in an effort to shift blame.
Operator error and controlled crash into terrain.
You know what else is interesting, although the vertical stabilizers break off all the time, they reattach themselves while in flight and virtually none of the passengers ever notice the phenomenon occuring. Creepy.
Why the focus on the vertical stabilizer, how come nobody ever questions the cockpit breaking off?
True, but having a wing break off in a high-speed dive is even more unsettling (although there are few around to tell that tale).
Taking an aircraft of this design and size into a 'full stall' is never done. It is highly unlikely that even the manufactures test pilot could have recovered from that condition. It is not like stalling a 'Cub". Many things happen including most likely the failure of the engines due to disrupted air flow. Swept wing aircraft are notorious for their stall recovery problems.
In general, this is a ridiculous bit of yellow journalism. Pilots and co-pilots of commercial aircraft must have an ATP (Airline Transport Pilot) rating, or the international/ICAI equivalent. This was no student pilot in the cockpit. Because of the nature of long international flights, both pilots must be qualified in commanding the aircraft. The overdramatization and sheer creative writing I read in this report is reprehensible.
As to what happened with this particular flight, that’s another thing altogether, but their representation of the co-pilot’s qualifications should have been left on the cutting room floor.
Airbus has known that the pitot tubes on some of their planes were faulty and susceptible to icing.
Agreed.
Doesn’t this 200 million dollar airliner have a GPS that could have given them their speed? My $100 Tom Tom can do that.
Keep in mind why the AP and AT disconnected; that was due to unreliable speed indications. Established procedures requires pitch / thrust config. Also, notice from the report that the plane entered a slight bank (which would entice an amount of sideslip). So counteracting the roll with additional pitch up would seem plausible.
However, one should keep in mind that flight testing of the A330/A340 in a very controlled environment, and clean, they do not exhibit any undesirable characteristics. To those flying light aircraft it is very much like a clean stall on a Piper PA28. With the addition of flap, they do exhibit a dynamic Q break.
Military fighter craft when in full stall with alfa > 45° exhibit a sensation that is markedly different than what is encountered at stall onset in a typical traning situation (e.g., alfa around 15-20°) and leave it pretty immediately.
There is a pretty stable ride, the aircraft is loose in roll but there is less buffeting then when at stall onset, it can be pretty disorientating especially if it is dark. The sinkrate is extreme, one needs to be very consitent and persistent to get out of it.
One thing worthy of speculation: what kind of pitch authority would the A/C have if there was significant tailplane icing? If the pitots are implicated as having experienced some manner of icing, what implications does that have with regards to the tailplane specifically, and more generally with respect to airfoil generated lift?
My understanding that a stalled airfoil continues to generate significant lift; put your hand out the window - palm down - at 45o while traveling 80 MPH down the highway (what happens?). Problem is that drag beceomes scuh a significant that forward velocity is greatly eroded.
The new procedure is designed to cover all stall conditions. It recognises that recovering the angle of attack might instead require a reduction of thrust, to regain pitch-down authority, as well as a loss of altitude.
It removes the need to prioritise take-off/go-around thrust in favour of restoring lift to the wing by reducing angle of attack. The procedure also points out that thrust should be re-applied smoothly, particularly because aircraft with under-wing engines have a tendency to pitch up, increasing the angle of attack, when power is applied.
Not an expert but with at least 10 of the icing incidents known would not this situation found it’s way into flight simulators. ?
Not an expert but with at least 10 of the icing incidents known would not this situation found it’s way into flight simulators. ?
too much simulator time, too much “always trust and fly your instruments” hammer in to this guy...for a pilot to hold his nose up to stall for 38,000 ft to his death because a ice over pitot tube giving a bad reading?....
head lock...
The sad thing is if the pilot just let go of the controls the aircraft would have probably done a better job on recovering then the pilot did
Stopped reading right there.
Obviously you have never flown with an ex-Military jet pilot.
Please google and do some research on the freezing problems these pitot tubes had particularly under these type of conditions and then come back and act informed.
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