promani

'At 2 h 06 min 04, the PF called the cabin crew, telling them that"in two minutes we should enter an area where it’ll move about a bit more than at the moment, you should watch out". Do we assume that the seatbelt sign was on, and the passengers were told to take their seats? Was the going so rough that the FA's could not be seated? (Okay maybe some were sleeping). With about 5 minutes to go before v/s became negative, I would have thought that they could have been belted in. But with so many passengers found unseated, I wonder if they were able to due to the aircraft's movements. What a way to go, poor souls!

RatherBeFlying

In my boyhood I was familiar with a number of biplanes where the airspeed sensor was a flat plate on a coil spring mounted against a scale on the interplane struts. However icing would change the drag coefficient and might even lock up the spring

Any blade antenna produces drag proportionate to airspeed that a force transducer could convert into knots. Whether the antenna people provide ice resistant coatings or proper heating elements is another question, but at least such a sensor would not be vulnerable to clogging. To be useful such a sensor would need to provide usable indications at altitude where the available speed range can be quite narrow.

JD-EE

promani, (and others) this foaming at the mouth to find somebody to blame, particularly a deceased somebody, is unseemly. It is also most definitely not BEA's charter. Their charter is to make aviation safer through impartial investigations of accidents.

It does not good to assign fault to say, the pilot, and wash your hands of the entire event leaving it to the court to finish stomping on a corpse to help some people obtain an emotional release (and financial killing.) The BEA must figure out WHY something failed and correct that situation.

Let's use some fanciful names and events to remove some of the emotion for a moment. Please bear with me here to get a notion of what I mean. We're not here to assign blame. We're here to make aviation safer.

Suppose we have a floobie. A floobie pingles widgets. This is a very complex floobie. It requires a rangant for it to function. At any given time it typically has hundreds of users per floobie. It has failed killing many users and the available data indicates the rangant "obviously" did something stupid.

Is this enough to make using floobies safer? It may satisfy some blood lust. "Let's take that rangant out, slap it around, and hang it from the yard arm even if it's already broken beyond repair."

It does not satisfy the need for safer use of floobies. We must figure out why the floobie's rangant twisted its left plooker button. Did the rangant get spurious inputs? Was the rangant's programming (training) incorrect or in some way inadequate? Was the rangant overloaded with conflicting data?

What actions can take place to make floobies safer to use? Some here seem to be suggesting ripping out all the telserboxes from the floobie and make the rangant do things the old way, fessling the grommetvents directly. There is a small point here if one neglects documented safety records that state usually floobies that use telserboxes all seem to pingle along more safely than when the rangant fessles grommetvents directly.

So it seems we must make sure the rangant does not mess up again under the particularly unusual conditions that contributed to its incorrectly twisting the left plooker button. What can be done to "clean up" the data input to this poor overloaded rangant when it is faced with a cascade of failures such as observed? Could better programming (training) of the rangant for real world conditions help? When their programming is tested they already know the test. "We start nearly feeblevetzed and you have to recover from a complete feeblevetz." What does the Rangant do when it's "surprised" (its programming had not prepared ot to recognize this) by feeblevetzing conditions?

It seems to me this latter objective is more important than the emotional release obtained by stomping that already dead defective rangant into itty bitty pieces in a fit of judicial temper.

And, yes, this has a deliberate resemblance to the case at hand here. Somebody determined enough could plot it out. I'm seeing shouts of "kill (blame) the pilot!" I don't see realistic searches for methods to repair the situation? I'm not even seeing many efforts to determine why a rangant might exhibit anomalous behavior when faced by the stimuli set we know, perhaps with the inclusion of some stimuli we don't know.

bearfoil

Machinbird

I had envisioned a tube similar to pitot, and in the airstream, but blunt, to forestall abrupt icing. I also think to alleviate unwanted angle sensing, the "bulb" could have "Cells" sensed through a computer that selects the group closest to stagnation point. Not a panacea, but perhaps a bit more ice resistant, and alleviating Drain hole aberrations, etc.

Sat in your old office once upon a time, now there's a foxhole!

kilomikedelta

JD-EE: 'Twas brillig .... excellent analogy.

henra

JD-EE:

Great Post !!!

BJ-ENG

@Machinebird

You might find this of interest:
http://www.nasa.gov/centers/dryden/p...ain_H-2379.pdf

http://www.spaceagecontrol.com/nasa-tm-104316.pdf

JD-EE

kilomikedelta, henra - thanks guys. I was biting my fingernails over that one.

CONF iture

HN39, thanks for the data.
I took the liberty to change a bit the presentation just to help for the clarity.
Hope you don't mind.

Minorite invisible

The PF commanded nose up in manual flight, alternate, law. The aircraft was just attempting to trim the aircraft to comply with pilot input. Quite normal.

bearfoil

No offense, but somehow making light of the inadequacies that may have caused so many to perish, I can think only of a possible reason why.

The Art is not the best, but it is the best, all things considered.

respect

milsabords

"Use of a gas behind the membrane would not work because of PV=RT."

Mariotte's law is not a problem: V, R are fixed values. T is measured, so P can be computed.

mm43

HN39

Thanks for the data set.

JD-EE

Well put. "If it ain't broke don't fix it" could be substituted for, "If it ain't fixed, it'll be broke". Your little rant was fair and to the point, but you are well aware that innovative and practical solutions are the bread and butter of this thread. Just a pity that at this juncture there is too much butter on the bread.

CogSim

This post is to retract my earlier assessment that the initial response from PF may have been wrong. After spending a couple of days studying the report, I'm not sure anymore. It is unfortunate that BEA has released so little factual information. There is very little to go by. I'll just post some questions I scribbled in the margins of the report here before taking leave and waiting for the July report.

From 2 h 10 min 05 (4), the autopilot then auto-thrust disengaged and the PF said "I have the controls". The airplane began to roll to the right and the PF made a left nose-up input.

Why nose-up. Was this required to arrest the roll to the right?

The PF made nose-down control inputs and alternately left and right roll inputs. The vertical speed, which had reached 7,000 ft/min, dropped to 700 ft/min and the roll varied between 12 degrees right and 10 degrees left.

Propensity to roll right again?

The airplane was subject to roll oscillations that sometimes reached 40 degrees.

Were these oscillations symmetric? These oscillations correspond to a sharp turn to the right on the track shown by BEA in figure. Again reasonable to assume a/c wanted to roll right? Why?

Edit: remove nose-up comment.

The a/c seems to show a propensity to roll right from AP disconnect to end of flight, why?

My conclusion, there is more here than meets the eye. There is just not enough factual information to explain the oddness. There are enough doubts in my mind now to say the initial response of the PF was wrong.

Peace.

TLB

1. The BEA report of 2009 describes the pilot qualifications as follows:

]1.5.1.1 Captain (Let’s call him Pilot A) TT: 10,988 flying hours, of which 6,258 as Captain Hours on type: 1,747, all as Captain

1.5.1.2 Co-pilot (Let’s call him Pilot B) TT: 6,547 flying hours
Hours on type: 4,479 flying hours Note: It goes on to say: “ …This pilot’s licences allowed him to perform the duties of replacement pilot in place of the captain …”


1.5.1.3 Co-pilot (Let’s call him Pilot C) TT: 2,936 Hours on type: 807 Note: There is no mention of replacement pilot qualifications as per Pilot B above.

2. The BEA report of 27 May 2011 makes the following statements:

The Captain was PNF, one of the co-pilots was PF At 1 h 55, the Captain woke the second co-pilot and said "[…] he’s going to take my place"

3. I had always assumed that it was Pilot C who replaced the Captain as PNF in the LHS but given that Pilot B was the only one of the two co-pilots authorized to the replace the Captain, I now conclude that Pilot B (high time on type) was actually the PNF in the LHS while Pilot C (very low time on type) was the PF in the RHS at the time of the accident.

ChristiaanJ

JD-EE, good post, but...
I think the shouts are more in the line of "the pilot did it...", without ncessarily blaming him for not being able to cope.
Not quite true....
There are sugestions for improved instrumentation, improved (and less charged and confusing) displays, the addition of an AoA display, as well as better training. I agree with you there. Especially if the "stimulus set" is not static, but a complex "stimulus game play" that all plays out in a few minutes (which is a very short time...).

Minorite invisible

AF 447 had stall warnings and unreliable airspeed indications simultaneously.

The A-330 unreliable airspeed drill in clean configuration at cruise flight level calls for the pitch to be set at 5 degrees nose up and for thrust to be set at CLB (which in effect puts the aircraft in a climb configuration)

The Stall recovery drill calls for nose down pitch control with thrust to be increased smoothly once out of the stall.

Because the auto thrust disconnected, if the pilots did not move the thrust levers, the thrusts would have gone to CLB on their own (A-330 thrust levers are set t CLB detent when in cruise on auto-thrust). The pilot's initial reaction was to bring the pitch up to 10 degrees nose up.

49 seconds after the start of the incident, after another stall warning, the pilot pushed the thrust levers from CLB to TOGA.

May 30 EDIT:

When the Autothrust disconnects due to a fault rather than by pilot action, the thrusts do not go to match the Thrust Level Symbols (blue doughnuts) as in the manual disconnect, but freeze in their present position.

JD-EE

CogSim, regarding the apparently silly roll commands I got to wondering if the PF was, indeed, the pilot who replaced the captain and whether he adjusted the stick properly when he sat down. If the stick was maladjusted I can conjure in my mind the roll being a spurious input. Of course, that does not necessarily apply for the times the command was all the way to the stops.

Another question comes to mind. We have the autopilot then auto-thrust disengage. Then the PF climbs with a roll. Is there a procedure that would call for a climb on AP/AT disengagement? (And did the pilot make his input before, simultaneously with, or in response to the stall warning? The wording seems to imply he acted before (perhaps barely) the stall warning. Was the pilot starting the unreliable airspeed procedure? (It was tens of seconds later that the thrust levers were shoved to TOGA.)

It might also pay to know precisely who was PF. Reactions honed in past experience may have led to an action inappropriate for an A300-200. That would indicate a cure is better training, with a lot more "unexpected events" during the training flight. (This event may end up as a bonanza for the people who make the simulators as more time may be needed for more unexpected events.)

ChristiaanJ

Reading the various posts about UAS procedures, I have the impression they were all developed for low-level (shortly after T/O) UAS situations. In particular, I see the remarks/instructions about "preventing loss of altitude" (logical at low altitude).

Can anybody here tell this ancient (flight test engineer, not a pilot, and now retired, I should state), whether there are any formal high-altitude UAS procedures in existence (and trained), other than the basic "pitch and power"?
As implied earlier, the nose-up command "reflex" is understandable, if it results from an effort to "stop the altitude loss" in an UAS situation (inapropriate here).

Minorite invisible

French:

"Le PF exerce une action sur le manche en butée à gauche et à cabrer, qui dure environ 30 secondes."

English:

"The PF made an input on the sidestick to the left and nose-up stops, which lasted about 30 seconds."

The way the French version is written is ambiguous and could also be translated:

"The PF made an input on the sidestick to the left stop and nose-up, which lasted about 30 seconds."

A small detail, but one that must be cleared up nevertheless