More on AF 447

A summary of the accident investigation report is he
http://forums.theregister.co.uk/post...08/flight_447/

The summary references this annotated transcript:
http://www.popularmechanics.com/prin...ppened-aboard-
air-france-447-6611877?page=all

I haven't seen references to it anywhere else (maybe I don't get out
enough) but it deserves a read, especially as I have seen it written that
many GA pilots are being taught that the way to recover from a stall is
"open the throttle and pull the stick back to maintain altitude". Didn't
work this time!


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

I'd just read that article and thought the same. The guy's tens of
thousands of feet in the air going 100 knots and pulling back because
he's worried about losing altitude, absolutely amazing.


On Dec 8, 4:13*pm, Martin Gregorie
wrote:
A summary *of the accident investigation report is hehttp://forums.theregister.co.uk/post...08/flight_447/

The summary references this annotated transcript:http://www.popularmechanics.com/prin...ppened-aboard-
air-france-447-6611877?page=all

I haven't seen references to it anywhere else (maybe I don't get out
enough) but it deserves a read, especially as I have seen it written that
many GA pilots are being taught that the way to recover from a stall is
"open the throttle and pull the stick back to maintain altitude". Didn't
work this time!

--
martin@ * | Martin Gregorie
gregorie. | Essex, UK
org * * * |

On Dec 8, 6:13*pm, Martin Gregorie
wrote:
A summary *of the accident investigation report is hehttp://forums.theregister.co.uk/post...08/flight_447/

The summary references this annotated transcript:http://www.popularmechanics.com/prin...ppened-aboard-
air-france-447-6611877?page=all

I haven't seen references to it anywhere else (maybe I don't get out
enough) but it deserves a read, especially as I have seen it written that
many GA pilots are being taught that the way to recover from a stall is
"open the throttle and pull the stick back to maintain altitude". Didn't
work this time!

--
martin@ * | Martin Gregorie
gregorie. | Essex, UK
org * * * |

in the US, I have never ever heard of stall recovery being taught this
way in airplanes.

On Fri, 09 Dec 2011 15:39:50 -0800, Tony wrote:

On Dec 8, 6:13Â*pm, Martin Gregorie
wrote:
A summary Â*of the accident investigation report is
hehttp://forums.theregister.co.uk/post...08/flight_447/

The summary references this annotated
transcript:http://www.popularmechanics.com/print-this/what-really-
happened-aboard-
air-france-447-6611877?page=all

I haven't seen references to it anywhere else (maybe I don't get out
enough) but it deserves a read, especially as I have seen it written
that many GA pilots are being taught that the way to recover from a
stall is "open the throttle and pull the stick back to maintain
altitude". Didn't work this time!

--
martin@ Â* | Martin Gregorie gregorie. | Essex, UK org Â* Â* Â* |

in the US, I have never ever heard of stall recovery being taught this
way in airplanes.

IIRC the first time I'd heard of it was on here earlier this year.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

On Sat, 10 Dec 2011 00:39:46 +0000, Martin Gregorie wrote:

IIRC the first time I'd heard of it was on here earlier this year.

Read the Popular Mechanix article again - you'll find it discussed as a
recognised ATP stall recovery method, but only to be used when you'd be
too low for a standard stall recovery and hence wildly inappropriate at
Airbus cruising altitude. The speculation is that copilot#2 had only been
taught and/or practised that technique when flying manually.

Did you notice the other standout oddity: apparently no verbal hand-over
along the lines of "I have control"..."You have"?


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

"Tony" wrote in message
...
On Dec 8, 6:13 pm, Martin Gregorie
wrote:
... I have seen it written that
many GA pilots are being taught that the way to recover from a stall is
"open the throttle and pull the stick back to maintain altitude". Didn't
work this time!
in the US, I have never ever heard of stall recovery being taught this
way in airplanes.

I must have missed that lesson. Actually, GA pilots are taught to lower the
nose while simultaneously adding power. You don't try to climb until you have
recovered flying speed.

My first few hundred hours of flight time was in gliders. When I finally
decided to get my PPL in airplanes, my instructors found it very annoying that I
would recover from a stall by simply lowering the nose (consistently forgetting
to add power). I even did it once on my check ride! Something learned so well
that it is totally instinctive is very difficult to "unlearn".

Vaughn

As an A330 captain/instructor/check airman and author of numerous training materials on the A330, here's my take on the Pop Mechanics article:

Overall a pretty good article, but there are a couple of technical errors in the article and comments.

One statement is certainly correct: "Bonin's behavior is difficult for professional aviators to understand."
If the two pilots had simply sat on their hands when this incident first occurred, it would have all come out OK. There have been a number of similar loss of airspeed incidents due to the particular model of pitot tube (all since replaced). The incidents last only a short while. In all the other cases, competent pilots continued to fly the airplane in a normal pitch and power combination with no ill effects.
This was not a sidestick issue. In my opinion, this was a pilot competence issue. This is not a Boeing/Airbus issue either; Boeings have also stalled at altitude and subsequently crashed. It is inexcusable for the stall warning to have been going off for so long without positive nose-down input from the pilots. There is no extra energy to make a level flight (or climbing) stall recovery at altitude. A nose-down recovery is the only thing that will allow the angle of attach to be sufficiently reduced for a return to normal flight. At 2:10:30 they were well on the way to a recovery, but apparently failed once again to understand basic aerodynamics.

Consider also that the stall angle of attack at high altitudes is greatly reduced from that at lower altitudes (due to several somewhat technical aerodynamic factors outside the scope of explaining here). Having flown (and taught) high altitude stalls in an A330 simulator, it is not difficult to recovery from a stall in this regime, but the pilot has to actually DO IT.

When referring to TOGA "I'm in TOGA, huh? " he is referring to the TOGA position of the thrust levers - which is the full forward position used primarily for full-thrust takeoffs and go-arounds (as well as emergency maneuvers). Note that the engines are hung below the center of gravity; this produces a nose-up pitch moment, which also can reduce nose-down elevator authority. Had they actually pushed the stick forward (which they didn't for very long) they may have also needed to reduce power to aid in a timely stall recovery. This is the standard stall recovery now being emphasized in airline training.

"Thanks to the effects of the anti-icing system, one of the pitot tubes begins to work again. " The pitot tubes are constantly heated. This model of pitot tube was replaced with another about the time of this accident (some airlines faster than others). The internal geometry of this pitot tube is primarily responsible for the clogging - not a heating issue. Pilot selected anti-ice refers to engine or wing anti-ice.

When in dual input mode lights in front of each pilot flash illuminate to show that both pilots are making sidestick inputs. An option exists for an automatic warning to say "Dual Input" when this occurs. I don't know if AF had that option. Each sidestick has a button that allows that sidestick to override the other (the last one pushed has control). The same button also disconnects the autopilot. The override button is intended to override faults, and allow a complete takeover, not solve a fight over who has control (not that there was one). Airline pilot discipline is to be very clear on who is flying the airplane - and as we see in the article, when a transfer of control takes place , e.g., the statement: "I have the controls."

In alternate law, the same pitch law applies as in Normal law.That is, g-load/pitch rate demand. When the sidestick is in neutral the airplane is essentially stable in pitch. The pilots would need to push the stick forward to reduce the angle of attack and recover from the stall. The airplane would not pitch over by itself Cessna 172 style. But these airplanes are designed to be flown by professional aviators with training in these factors and type ratings in this airplane. The transcript indicates that there was a lot they did not understand.

As mentioned in one comment the stabilizer trim was virtually full nose up. This is a result of the sidestick being held back for a long period of time - not some design flaw or data error. (the flight control system moves the elevator to meet pilot demand, then automatically trims the stabilizer for efficiency). The full nose-up trim reduces the nose-down elevator authority - as it would on any airplane. Again, this may not have actually been factor since they didn't command a nose down attitude for the recovery anyway..

On 12-10-2011 15:21, vaughn wrote:
wrote in message
...
On Dec 8, 6:13 pm, Martin
wrote:
... I have seen it written that
many GA pilots are being taught that the way to recover from a stall is
"open the throttle and pull the stick back to maintain altitude". Didn't
work this time!
in the US, I have never ever heard of stall recovery being taught this
way in airplanes.

I must have missed that lesson. Actually, GA pilots are taught to lower the
nose while simultaneously adding power. You don't try to climb until you have
recovered flying speed.

My first few hundred hours of flight time was in gliders. When I finally
decided to get my PPL in airplanes, my instructors found it very annoying that I
would recover from a stall by simply lowering the nose (consistently forgetting
to add power). I even did it once on my check ride! Something learned so well
that it is totally instinctive is very difficult to "unlearn".

Vaughn



I used to do that too as a student, even though I started in powered
planes. I always thought it was much gentler on the airframe lower
the nose, get the speed back up a bit and then add power smoothly to
resume "level" flight. Always hated the abrupt addition of full power
as the nose was lowered and speed quickly came up and it sounded like
the engine was revving 500 RPM over redline and had to be retarded
fairly quickly to avoid going over redline. I suppose it's really
intended to minimize altitude loss as this is most likely going to
happen at low altitude vs at 29,000 feet

If this happened to me at 100 feet, I'm know I would instinctively jam
the throttle up to the carburetor! And I wouldn't be worrying about
redline

Ace

Mr. Palmer,
I think the side-stick controller was at least as a contributing
factor in this accident. With a conventional control yoke everyone in
the cockpit could have seen that the one pilot was pulling back on the
stick. A side-stick is off to the side - out of view - and I suspect
has much less travel.
But as you point out, the main problem is a lack of competence.
Mike Koerner