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AF447 Thread No. 3

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AF447 Thread No. 3

Old 30th May 2011, 09:38
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A few points:
That sounds real scary, if the pilot cannot control a primary control surface
Pitch Trim is always available to the pilots (save double Hyd failure).. just move the wheel and overrides all FBW. However, you'd have to be pretty confident / assertive to do it outisde Direct Law, not part of the training (save one exception discussed above for some operators).

Stalling - the training/understanding of airline crews is infrequent and limited in scope. SOPs / monitoring and warning systems are designed to warn of, and recover from at the approach to a stall. Expecting crews to comprehend what goes on beyond the stall i.e. IAS <100K AoA 40deg+ is unrealistic. Who knows even how far the certification went in this regard?

Please NB 2 x 757 also complete loss with UAS and the confusion that reigns over contradictory wearnings / instruments. As an industry I would not say we are much advanced from that point. You might just see a fair performance in the sim (and is the sim model correct? unlikely) in a "set" training package - to see that replicated 2-3 years later, at night, circadian low, with no warning I think unlikely to see a good % of well handled recoveries

Think where the industry is going. We could easily have only a cruise co-pilot on the Flt Deck (other pilot on a comfort break)...
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Old 30th May 2011, 09:43
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Code:
gums Until I see a good pitch moment chart as the one I posted for the Viper
again...... have a look at figure 6 in the this paper from BJ-ENG....

http://ntrs.nasa.gov/archive/nasa/ca...2005208658.pdf

but a CG at 29% is much better than expekted
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Old 30th May 2011, 11:36
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BEAs statement is a careful selection of established facts which must have been checked out carefully by legal opinion - so I think I think it is worth looking carefully at the words used - albeit in the English translation - does the French read the same? Maybe reading in too much?

the Captain woke the second co-pilot
Suggesting he was asleep, and could have been for a couple of hours - but within 5 minutes he was in front of the controls as PNF.

Captain attended the briefing
that was nice - he could have just said bye? OK a lot more would have been said in the 3 minute handover, but who was Responsible, Accountable, or just Consulted/Involved. (yes management consultant speak - RACI analysis).

PF said
we can’t climb much for the moment because the temperature is falling more slowly than forecast" and that "the logon with Dakar failed"
shows he knows near max alt, and not authorized to climb, and that they all knew that.

At 2 h 08 min 07 , the PNF said "you can maybe go a little to the left […]".
tentative subservient, he didn't like what he saw ahead.

From 2 h 10 min 50, the PNF tried several times to call the Captain back.
Repeating a comment in this thread too many pages back. PNF not happy with what PF is doing - but doesn't have authority to question?

At around 2 h 11 min 40 , the Captain re-entered the cockpit. The altitude was then about 35,000 ft,
Did they tell the captain that they had been to 38,000 ft and were now on the way down?
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Old 30th May 2011, 12:13
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Better WXR Training Needed?

Honeywell: Better wx training needed
Radar manufacturers should consider making equipment easier to use and displays easier to interpret, Honeywell safety specialist Dr. Ratan Khatwa told attendees at this year’s Flight Safety Foundation European Aviation Safety Seminar, held in Bucharest.
He added that better weather-radar training can improve pilots’ awareness and decision-making skills and help them avoid penetrating severe meteorological conditions.

NTSB studies show weather to be a factor in about 25 percent of all U.S. flying accidents between 1994 and 2003. Khatwa said initial and recurrent flight crew training should cover fundamental concepts in six areas of weather-radar operation: beam coverage, Earth-curvature effects, antenna stabilization, tilt and gain management, calibrated weather and range. System limitations, such as attenuation and the significance of green radar “echoes” at high altitude, also should be covered.

These recommendations arise from analysis of pilots’ difficulties and concerns uncovered while Honeywell was developing its RDR-4000 radar. Khatwa’s study included a human-factors evaluation of flight-crew radar use, a global survey to assess pilots’ fundamental understanding and perceptions of training, and analyses of weather radar-related incidents and accidents. He concluded pilots did not understand fundamental weather-radar concepts; typical equipment use precluded detection of severe weather; and dedicated training was not standard practice.

Khatwa pointed out that current radars are concerned primarily with weather analysis and avoidance, proper interpretation of which depends on pilots’ adequate understanding.

Honeywell’s RDR-4000 human- factors research showed that almost 70 percent of pilots were dissatisfied with weather-radar training. From the survey, Khatwa concluded most operators do not provide initial or recurrent weather-radar training; most available training takes place on the job; there is little incentive for operators to provide training since regulators do not require it; many pilots do not understand weather radar, including its limitations; fundamental concepts of weather radar are “poorly understood”; and pilots want recurrent training.

To understand pilots’ weather-radar use and any difficulties, Honeywell conducted a comparative evaluation of independent flight-crew groups using current equipment or new radar-display modes. The PC-based exercise observed the behavior of 13 pilots during several scenarios involving weather-radar use. Overall, “significant weather” events were detected on almost 82 percent of occasions, with pilots correctly deciding on action necessary to avoid penetration 70 percent of the time.

Incorrect pilot action involved improper management of weather-radar tilt, gain or range, continued flight toward significant weather and imprudent weather-avoidance decisions. All pilots failed to recognize the vertical position of each of two weather cells. Khatwa emphasized the need for pilots to be cautious about green radar echoes at high altitude, since these indicate “potentially hazardous” conditions.

Analysis of actual flight-crew radar operation and interpretation was ultimately restricted because the study could not include “many other critical factors, such as provision of timely weather information, accuracy of such data, role of ATC and regulator” and other considerations. This part of Khatwa’s study drew on data covering fatal and nonfatal accidents and incidents (fixed- and rotary-wing) that involved global single- and dual-pilot business, public transport and cargo aircraft operations reported by nine different worldwide safety agencies between 1987 and 2007.

Excluding occurrences involving training flights, sabotage, terrorism, military action or insufficient weather-radar information, Honeywell researchers found just 14 relevant events. A quarter of these instances were fatal, and half of the aircraft involved were substantially damaged or destroyed. Some 57 percent of the accidents or incidents took place in instrument meteorological conditions, 50 percent occurred during cruise, the same proportion was in daylight and another 35 percent occurred between top-of-descent and destination.

Switching off the radar, despite forecast weather and prevailing conditions, or pressing on in the face of adverse conditions were cited as examples of poor planning. Other examples of poor decision making included making landing decisions based on the experiences of preceding aircraft that successfully penetrated convective weather; flying through gaps between closely spaced storm cells, rather than around the thunderstorm; and flying close to squall lines.

In addition, the operation of weather radar or radar-display interpretation were “not necessarily optimal” in two thirds of occur-rences, said Khatwa, who cited five problem areas: improper tilt operation or management; improper use of gain control; misinterpretation of ground returns; weather radar “off,” despite known cumulo-nimbus cloud; and insufficient appreciation of radar limitations and their impact on displayed images.

The Honeywell study shows that crew weather-radar training had not been provided in half of the accidents/incidents. Pilots talked about “trial-and-error experience” and “information [obtained] from other pilots,” an approach that Khatwa concluded can “lead to improper radar operating procedures and techniques.”

Honeywell Aerospace Pilot Survey Findings

In conducting a survey about the RDR-4000 weather radar, Honeywell safety specialist Dr. Ratan Khatwa asked more than 50 ATP-rated pilots about their experience with weather radar. The average age of the respondents was 52 years; the average flight time was 12,500 hours. The answers these experienced pilots provided were illuminating.

• 62 percent of the pilots surveyed answered correctly that a straight radar beam is not aligned with an aircraft’s current flight level (because of Earth curvature)

• 15 percent mistakenly thought that antenna down-tilt was required to offset a nose-up pitch angle. (That is offset by antenna stabilization.)

• 63 percent did not appreciate the need for weather-radar antennas to be set to compensate for earth curvature, which blocks weather targets beyond, say, 150 nm ahead for nominal cruise altitudes. “Curvature [effects] become noticeable at ranges above 40 nm, and if ignored can lead to weather-image interpretation errors,” said Khatwa.

• 55 percent of pilots did not realize that a weather target falling inside the radar beam will not necessarily be shown in its true color on the display. “The color selected for display is a direct function of the power returned to the receiver. Where the beam is partially filled, the total power returned may not represent the calibrated value associated with the target cell,” he said.

• Five in every eight pilots incorrectly thought green (short-range) radar targets shown near to cruise levels above FL310 need not be avoided. “Typically, at these altitudes, targets are less reflective. At high altitudes, there is a possibility of unstable air and hail above the storm cell. It is therefore not advisable to penetrate the less-reflective part of the storm top,” Khatwa explained.

• 73 percent of flight crew understood that antenna tilt angle does not need to match a climb (or descent) angle to detect weather on their flight path. “The antenna should be pointed at the base of convective weather during climb. Generally, the lower 18,000 feet is the most reflective part of the storm.” Radar can be used to analyze weather characteristics (such as vertical extent of cells) and to avoid strong convective activity. “Returns along the flight-path angle may not provide full indication of storm intensity and turbulence levels [to be encountered within the cell].”

• Almost 90 percent of pilots did not know the range at which their current weather radar was no longer calibrated and did not show returns at their true levels. Radar beams broaden with distance, so a smaller proportion is filled with moisture. “At shorter ranges, returned power is more representative of the target cell, and it is more likely to be displayed at its true calibrated value. Typically, returns are calibrated within a range of 60 to 80 nm.”
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Old 30th May 2011, 12:25
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sensor_validation

At 1 h 55, the Captain woke the second co-pilot and said "[…] he’s going to take my place".

...

Between 1 h 59 min 32 and 2 h 01 min 46 , the Captain attended the briefing between the two co-pilots, during which the PF said, in particular "the little bit of turbulence that you just saw […] we should find the same ahead […] we’re in the cloud layer unfortunately we can’t climb much for the moment because the temperature is falling more slowly than forecast" and that "the logon with Dakar failed". The Captain left the cockpit.
From a human factors point of view, I'm with you on that.

How can a guy be woken up at 1:55 and at 2:02 be in charge (albeit as PNF) of the A/C, whatever the briefing he has been given ?
When s..t hits the fan 8 minutes later, I am pretty sure that the poor guy was not totally up to speed.
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Old 30th May 2011, 12:38
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Except in the “New findings” part at the end, the BEA update report is sliced into paragraphs that start with a time stamp. Each paragraph contains details like general configuration of the flight (e.g. speeds, AoA), sidestick controller inputs, audio alarms, tidbits of dialogue between pilots where and when BEA thought the information significant. Clearly what is exhibited in each paragraph was observed between the initial time stamp and the time stamp of the next paragraph.

With this in mind and noting that between 2 h 10 min 16 and 2 h 10 min 50 (citing the report) “The PF made nose-down control inputs”, I venture to submit that it is quite unclear what exactly caused the zoom climb to 37500 ft and this is a hint that BEA intends to closely examine this point.

Whether it was pilot induced or something else, this phase of the accident played a major role in establishing the confusion that followed.
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Old 30th May 2011, 12:41
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A sleepy PNF is better than none I assume?

Rather than worrying about the state of the PNF, if we are going to read things literally then 'THE PILOT woke the Co-Pilot', not "had him woken" so it is a good job this did not all happen at 1:55am with just one pilot, one asleep and the captain out of the cockpit.

It seem illogical to criticise how awake someone is, when there are probably numerous occasions when you are happy to accept just one in the cockpit.
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Old 30th May 2011, 12:48
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Graybeard
Ok, Confiture, maybe you have a logical explanation why the GS reported was the exact same 107 kt as the vertical velocity. See post #552
I would also presume it is a coincidence, but ...
why coincidence?

what did you think how BEA create the 3D flight path picture (last 5 min of flight) in the report?

they know surely save the 3D pos of LKP and the 2D pos of the crashplace, and they have truly the acceleration X/Y/Z from the box, and a lot more information with more or less reliability,

they puzzle a line over the two save points and try to put in as much as possible of the information, always checking if it is plausible with the acceleration .....

and if the flightpath ends with 45 deg then the GS is alway equal VS.......

no coincidence


p.s. by the way, how did you realy manege the calculation of the flight path angle if all avionic people use feet in Z direction and miles in X and Y, did you first convert the miles in feet? or use a scaled chart? or exist a calculator with the tangentfunction (feet/miles)
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Old 30th May 2011, 12:59
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RON51, TurbineD & that Trim Wheel

RON51 and TurbineD

Thanks, two worthwhile & very relevant posts a good few pages back (blink and we have another 5 or 10 new ones!)

One on the A330 TCAS zoom climb and the other on sensible software strategies

======= That Trim Wheel ================

Despite acknowledging the persistent nose-up control commands and their over-riding effect on the outcome, I still cannot avoid glancing suspiciously (in my mind's eye) down at that trim-wheel - and its 'apparent invisibility' - and too, its apparent culpability... almost 'by accident ' a dangerous approach to its presence, usage and modus operandi seems to have developed within AB and Airline SOP

What would the certificating and licensing authorities make of the (reported) 'slap wrists very hard if you ever touch it' mentality ?

Surely, that is why it has become 'invisible' as others have intimated earlier...

We really must focus heavily on HR (Human Response) issues - despite the weather, despite the icing, despite the UAS and despite initial AP/AT response (which perhaps was fairly benign, contrary to original speculation).

.. and on flight-crew selection and training.
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Old 30th May 2011, 13:24
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Originally Posted by CONF iture
That is not exact. Thrust is frozen until thrust levers are moved, so it could be anywhere between idle and climb thrust depending how was the thrust level at the time of the malfunction.
Not true. When auto-thrust is turned off, the engines will adjust thrust to match the two thrust level symbols (blue doughnuts). In this case, the auto thrust likely disconnected in cruise while the thrust levers were set to CLB. Without a pilot action, this would cause the thrusts to be increased to CLB to match the thrust lever symbols.


EDIT: I TAKE IT BACK, CONF iture was correct.

What I wrote is true only for voluntary Auto thrust disconnect. In case of involuntary disconnect, the thrusts are frozen at the actual power settings

FCOM 3.02.22 Page 2

Last edited by Minorite invisible; 30th May 2011 at 13:50.
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Old 30th May 2011, 13:29
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Originally Posted by CONF iture
Don't forget that this procedure is new from December 2010 and therefore was not in force at the time of AF447.
You are correct on that one. The old procedure called for the pilots to power himself out of the stall with minimal altitude loss. Nose down and power reduction were only to be used in a Note, if method one did not work.

So in this pilot's mind, both Unreliable Airspeed Drill and and Stall Recovery procedures would require power.

UAS would need nose up 5 degrees with CLB power while the stall recovery would require to maintain approximate pitch and TO/GA.
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Old 30th May 2011, 13:37
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RON51 & TurbineD & HarryMan

More about that trim wheel visible to all 3 pilots in the cockpit ...

Post #502 (14 Mar 11) by PJ2 on the Tech Log thread gives very good background information for the Trim Wheel/THS discussion. Post #502 contained this image – now annotated with A the main trim wheel and B the vernier scale for the THS.


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Old 30th May 2011, 13:42
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Originally Posted by Minorite invisible
You are correct on that one. The old procedure called for the pilots to power himself out of the stall with minimal altitude loss. Nose down and power reduction were only to be used in a Note, if method one did not work.
Is this confirmed by any AF folks?
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Old 30th May 2011, 13:57
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Rob21

In (American) aeronautical engineering English, incidence is the angle between the wing and the fuselage. With the exception of a very few airplanes, it is fixed. Angle of attack is the angle between the wing and the relative wind. I don't know the French phrase for angle of attack.

Last edited by Tailspin Turtle; 30th May 2011 at 14:15.
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Old 30th May 2011, 14:12
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My mistake, "Incidence" in French is angle of attack...
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Old 30th May 2011, 14:14
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Originally Posted by paull
Quote:
Originally Posted by Minorite invisible
You are correct on that one. The old procedure called for the pilots to power himself out of the stall with minimal altitude loss. Nose down and power reduction were only to be used in a Note, if method one did not work.
Is this confirmed by any AF folks?
The FCOM reference is 3.02.10 Page 10. I only have the 2010 version. Someone would need to dig up the old version.
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Old 30th May 2011, 14:20
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Rob21

Also, according to the interweb, some Brit aeronautical publications reportedly use angle of incidence to refer to angle of attack.
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Old 30th May 2011, 14:51
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AF "procedure anormale complementaire Stall warning"

Hi there
page 97 of http://www.bea.aero/docspa/2009/f-cp...cp090601e2.pdf
you will find the AF "procedure anormale complementaire Stall Warning":

during any other flight phases after lift off
Thrust levers.............................TOGA
Pitch Attitude............................reduce
Bank Angle...............................roll wings level
Speedbrakes.............................check retratcted
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Old 30th May 2011, 15:02
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Hi Minorite invisible,

I have a copy of QRH 2006 for A320 series and there is NO Stall Warning procedure. The closest is "Low Energy Warning" which basically says:

"The Speed Speed Speed synthetic voice is triggered every 5 seconds , whenever the aircraft energy goes below a threshold under which thrust shall be increased to recover a positive flight path angle.
_Thrust Levers.... Push
Increase the thrust until the warning disappears."

The Stall Recovery QRH was introduced in May 2010.

Could the crew of AF447 have confused "Stall Stall" synthetic voice with "Speed Speed"?
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Old 30th May 2011, 15:11
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Rubberband2,
It matters not how big the trim wheels are in real life. When you are trained to treat them as a piece of furniture inflight, it is effectively in the minds eye a piece of furniture and not the solution to "my" immediate flight control problem.
I believe I am in agreement with HarryMann on the importance of training to use this equipment so that it does not remain a piece of furniture. The control power of the THS makes the elevator into little more than a trim tab by comparison. (And I do have experience with flying jet aircraft with this control surface arrangement)

Last edited by Machinbird; 30th May 2011 at 15:19. Reason: Broaden statement.
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