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AF 447 Thread No. 6

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AF 447 Thread No. 6

Old 15th Aug 2011, 12:56
  #41 (permalink)  
 
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mm43, I seem to only be able to dream about a circadian rhythm that even approximately matches Earth's. I often joke I was born on another planet. Days about 28-32 hours long are ideal for me. And if I find myself working on a tough problem even that goes away. "Shop 'til you drop," is rhetoric, "Code til you drop," is reality, it seems. And when I do synchronize it's about "1200 to rise and 0400 to bed" in the local TZ no matter where I am. (SIGH!)

"That gurl ain't normal!"

Maybe they need to find pilots that can work well at night? (Probably there aren't near enough of them to matter.)
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Old 15th Aug 2011, 13:39
  #42 (permalink)  
 
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JD-EE, #41

"That gurl ain't normal!"

I dunno, sounds quite familiar to me :-).

Many years ago, before settling down to the requirements of family life,
kid's routines and defined working hours, I used to work around the
clock. Finished the day later, got up later, until I worked right round
to "normal" hours again. Something about solving difficult programming
or other design problems that really need long, uninterrupted sessions
to solve. Added to that, there's less noise and other distraction at
night, especially in the city.

Still have sessions like that occasionally even now, but not so
frequently...
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Old 15th Aug 2011, 14:52
  #43 (permalink)  
 
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Why not announce the measured angle of attack in the stall warning?

Then, after the warning, when in a stall, go into AOA (stall) ALARM mode.

Or, if AOA is past that of stall, why not have a voice that says, "Aerodynamic Stall"?
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Old 15th Aug 2011, 16:08
  #44 (permalink)  
 
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Originally Posted by gums
I must point out that the accident started when air data sensors went south. So what do we do when that happens?
Use manual control to set and keep five degrees nose up, wings level attitude. Don't think about ergonomics, stick deflections, active control law or whatever else just use whatever control input is necessary to maintain 5 ANU. Set climb power. Ask your assisting pilot to dig out QRH and find attitude and power setting for weight, altitude and phase of the flight. Oh wait... that's exactly what "Unreliable airspeed" drill memory items tell you to do.

Trick is to have each and every airline pilot remember them and perform them flawlessly when his body clock says its 4AM, when he's jet-lagged, when he hasn't handflown the plane above FL100 for ages (if ever), when he does less than half a dozen manual landings per month, when he has never experienced control laws degradation and protection loss in real life and only seldom in simulator, when his knowledge of the principles of flight is lacking as he was only made to memorize the multiple choice answers to pass ATPL exams, etc... Whoever patents practical solution to this problem will quickly become millionaire.

Originally Posted by gums
He was too early for the AA regional ATR accident when the A/P was feeding in control deflection due to ice build up. When all went to hell in a handbasket, Sad sad, and there was also some distractions in the cockpit for ten or fifteen minutes before A/P disconnect.
Simmons Airlines crash at Roselawn is a fantastic example of damage that zealous investigation can do to the efforts of increasing the flight safety. NTSB was after ATR and DGAC, BEA was set to defend them at all costs so went after pilots and in-between, many aerospace professionals who would benefit from understanding what actually happened at Roselawn were hopelessly confused.

A/P wasn't feeding any control deflection as ice was accumulating. Ice accumulation was light to moderate and did not affect the overall aerodynamics or performance of the aeroplane in any significant way. It was ridges of ice that formed on outboard parts of the wings, behind the de-icing boots that doomed the flight. It was result of flying with low speed and low AoA (feat made possible by extending the flaps in holding pattern to reduce pitch and improve passenger comfort) through area of supercooled large droplets - a largely unknown meteorological phenomenon at the time. These ridges destroyed ailerons' aerodynamic balance and caused hinge moment reversal at pretty low AoA - instead of centering under dynamic pressure, ailerons snapped to full right wing down position and that's what tripped the autopilot, surprising the crew and leaving them with roll control that needed very heavy force to move away from extreme position. Control was regained once, sadly lost again and when it was regained second time, there was no room to recover. Stabilizer and outboard portions of wings separated at 375 kts and 4G (IIRC Vmo on 72-200 was 230 kt). What got just cursory mention in NTSB report is that F/O tried to extend the flaps again as the aeroplane rolled, but as the speed was above limiting for flaps 15, flap extension was inhibited. Quite a reasonable feature that prevents blowing the flaps away now prevented recovery. Take note those of you seeking solution in more technology.

NTSB claimed that ATR and DGAC were aware of possible roll anomalies with ATR, yet they designed, certified and produced aeroplane as it was. Of course they knew about aileron hinge moment reversal, wind tunnel tests found it at 26 AoA, so far outside flight envelope that they never mentioned it to pilots. Bear in mind that ATR has very malign natural stall tendencies, it needs to be fitted with stickpusher to get certified and if you ever actually stall her, only luck can prevent your last flight from becoming hot topic on PPRuNe. During icing testing, no untoward effects of ice on controls were observed as there wasn't the method, and still there is none, for icing tankers to create SLDs so I really don't think there was conspiracy on ATRs and DGAC part to hide the dangerous side of ATR from her operators.

However, BEA played dirty. It tried to shift the focus from aeroplane to pilots and accused the crew of virtual dereliction of duty in critical phase of flight. That's where "distraction in cockpit" and "severe icing" myths mainly came from. Yes, there was cockpit banter but it was not out of ordinary and did not distract the crew from flying. The crew noticed ice accumulation and turned on de-icers. Their decision to hold with flaps was slightly unusual but not unreasonable as no one at the time knew that it could turn lethal. Our unlucky colleagues were test pilots without them ever realizing they were so. As Peter Garrison brilliantly summed up:
Airplanes were picking up the ice since there were first airplanes. They get heavier and draggier, they propellers vibrate and engines overheat but pilots don't expected their controls to slam to stops without warning.
All you BEA bashers, please take no comfort or support to your fancy theories from my opinion on BEA's handling of Roselawn crash. IMHO, BEA is doing terrific job with AF447 investigation and there's quite easy to see whether report gets excessively biased: just check factual information against analysis, conclusions and recommendations to see if there's large discrepancy, which is good indication of foul play. One just needs a bit of aeronautical salt to do it.
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Old 15th Aug 2011, 19:32
  #45 (permalink)  
 
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JD-ee:

How many UAV get plinked from the ground?

Well, given the dozens of various types and models, and operating parameters ... some are harder to deal with from the ground than others. I am guessing Global Hawk is pretty safe from ground fire.

For every innovation people eventually come up with a counter.

@ RAT 5
I've not read the whole thread, or report yet. However, there are many references here to lack of airspeed. Surely there was a ground speed readout. Thus there was not a total loss of speed indication.
This sub topic has been going on in each AF 447 thread.

The aircraft flies within the fluid medium, fluid being air. To see how important this is, try this exercise on your Ground Speed suggestion:

Fly a Cessna 172 at 100 kts IAS into a forty knot head wind.
GS ~ 60 knots.

Turn 180 degrees and try to fly at 60 knots using your ground speed as a reference.

Did you stall, or not?

It's much easier to do in a Jet Ranger, eh?

Even more interesting, take your Airbus A330 into an approach for landing at 155 knots, flying into a 40 knot head wind, using your ground speed for reference.

Do a touch and go.

Perform a tear type turn drop and then fly an approach to the same runway, opposite direction, using your ground speed as your speed reference ... and fly that 115 knots ground speed all the way to touchdown.

The landing might be firm, eh? Possibly short as well.

It seems to me that the point of the UAS drill in the A330 QRH is as follows:

There are charts for known best estimate pitch and power combinations, which will suffice (if you remember them) until you open the QRH and sweeten your pitch and power to match the closest number to "perfect" that will work to keep you in the safe operating zone until your pitot tubes, or you static ports, or whatever, unscrew themselves and airspeed indication returns to normal.

This "groundspeed" solution appears to me a solution in search of a problem, though I do understand the new feature in the A380 (an option) uses inertial inputs to aid in such situations.

From my PoV, over engineering.

Last edited by Lonewolf_50; 15th Aug 2011 at 19:52.
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Old 15th Aug 2011, 20:12
  #46 (permalink)  
 
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One such inequity. By Proxy, the designers of AB LAW were flying the LOC right along with the pilots.

The Pilot apparently misconstrued, mishandled, and became out of the control loop.

The LOOP was integrated into the airframe from the outset. It's shortcomings, no less then the Pilot's, are on display.

"Doing what was designed", is not a defense, it is an indictment.
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Old 15th Aug 2011, 20:34
  #47 (permalink)  
 
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@Lyman

SPOT ON
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Old 15th Aug 2011, 20:43
  #48 (permalink)  
 
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"Doing what was designed", is not a defense, it is an indictment.
No, it isn't. Like any machine, if it's mishandled it can bite.
If you built a bulldozer that someone drove onto the ice, and it fell through because the ice was too thin for a bulldozer, do you deserve an indictment?
If you built a car that someone drove off a cliff because he was going too fast for the corner, same question?

I won't keep going, because I know you get the point. The A330 is a terrific aircraft. ...and like every aircraft ever built, it can fall out of the sky if it's handled incorrectly. Sure, there are a few tweaks that could maybe help the next crew that finds themselves in the exact situation as AF447, and they're probably worth doing... But the biggest message here by far is:
- The lack of handling skills displayed by the PF,
- the evident lack of crew discipline or "professional" standards displayed by all crew members,
- and the obvious lack of training that allowed those first items above to exist, thus enabling the accident.
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Old 15th Aug 2011, 20:48
  #49 (permalink)  
 
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- The lack of handling skills displayed by the PF,
- the evident lack of crew discipline or "professional" standards displayed by all crew members,
- and the obvious lack of training that allowed those first items above to exist, thus enabling the accident.
To make a long story short:

Sidestick NU - no stall warning
Sidestick ND - STALL STALL

In addition, no tactile feedback at all....
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Old 15th Aug 2011, 20:56
  #50 (permalink)  
 
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Three

Let me describe a sitiuation, see what you think. The zig zag of the Pitch trace is straightforward.

The trace of ROLL is interesting. In DIRECT, 447's Roll is difficult to define.

Admittedly back and forth, and within reasonably close tolerances in both directions, the argument can be made that this ROLLING saved the a/c from a spin. Let's assume that is the result, since each excursion seems to have been met with a force sufficient not only to arrest the Roll, but to command a reversal. Perhaps divine intervention, no matter!

Who would lay claim to such a result? The Designers? Make her titchy so that Roll can be managed quickly? Not likely.

Or is it? She Stalled, and crashed. But she did not SPIN.

Theoretical, but discuss?
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Old 15th Aug 2011, 21:04
  #51 (permalink)  
 
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With all due respect Lyman, that's a poor excuse.

Several UAS incidents in the A330/340 preceded this one and none of them ended up in the drink, because in all cases the crew figured out what was going on and either applied the correct procedure or improvised one of their own to get them out of trouble.

If the design was so faulty as to take the crew out of the loop in every case then we'd be looking at more than one fatal incident due to LOC following UAS in an A330.
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Old 15th Aug 2011, 21:12
  #52 (permalink)  
 
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What's to discuss Lyman? It's twitchy in roll when stalled? Please... That it mushed the way it did, rather than spin, may have as much to do with the somewhat aft CofG as it did the PF's valiant attempts to control it. Either way, the aircraft shouldn't have been stalled, and when it was, it should have been recognized.
For those two deadly faults, I feel rather confident pointing to things like AF's training, their SOP's, and their culture of standards and behaviour (which is likely encompassed within SOP's, but not ever having been a part of flight crew, I wouldn't know)
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Old 15th Aug 2011, 21:12
  #53 (permalink)  
 
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Dozy and 3hole,
As JD-EE already said, "stop feeding the troll....."
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Old 15th Aug 2011, 21:13
  #54 (permalink)  
 
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I am not now, nor have I said the design was faulty. It worked. It did not cause this loss. Please, please, slow down.

But to say it did not cause the crash is not enough. Neither is it fair to lump it all onto the Pilot.

It is not sufficient to design a system, sell it, and then neglect it. Beyond convenience, the politics are too cute. Teflon for all save the Pilot?

It was not supported well, and it was not supported in a myriad of ways.

Only a fool would repose in an imagined "perfection", to avoid responsibility of any kind.

Or a child.

For the record, I will stipulate that CONCORDE is an icon. All who have helped her live, and serve, should be honored. I mean it.

If one has something to say, one may say it.

3holelover. Having pointed at those two, do have some pointing left? What makes you think the Pilot, in Rolling, had any effect on preventing spin? I doubt it was so. He can't have been that intuitive......

DOZE You are correct in every way. There is less Truth in correct, than there is correct in Truth? Putting a stop to the discussion seems to be in vogue.

PJ2 He did NOT PITCH the a/c up to 15 degrees, at least not all at once.
Each Pitch Up was 'levelled off', as I read the Trace.

At Each Pitch up, PF may have felt a slowing, and NOT felt a continuation of NU.

IOW, He may well have thought that his Pitching Up solved an overspeed, albeit incrementally. Absent cues, he may have inferred an attitude closer to level than markedly NoseUp. The lack of THS Trimming on the way up shows us this. Several short and sequential commands for slowing. Instead, it was an ascent by degree, as I see it.

It is most unfair to propose that the Pilot merely wanted 15 degrees nose up. If that was so, the Ascent would have included the THS?

Throughout, the Pitch track is ragged, at least to me. Save until post STALL.

Stand to be corrected. And no shame in that, if by you.
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Old 15th Aug 2011, 21:47
  #55 (permalink)  
 
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I agree that just keeping attitude and power that were there when UAS is encountered is pretty good tactic for dealing with UAS. however, drill I was taught was quite good too and it's not add 5 degrees pitch, it's achieve and maintain 5 pitch above FL100 or MSA, which would make whopping 2.5 pitch up from usual cruise attitude, or at least that was the way I was taught on the bus. That attitude combined with climb power was calculated to keep one away from overspeed and stall so I find FCTM warning (we didn't use Airbus documentation, ours was airline tailored) about possible overspeed a bit worrying. PJ2, could you please post what are current memory items for 330 if crew somehow concludes that safe conduct of flight is indeed jeopardized by having unreliable speed?

Originally Posted by PJ2
It can be reasonably posited, though of course not confirmed, that the PF executed the pitch-up as a result of pitot failure and the memorized response, intended for the takeoff phase only. There is no other reason that makes sense as to why the PF would instantly pitch the aircraft up to approximately 15degrees.
Reminds me of misapplied tailplane stall procedure theory that was put forward when Colgan 3407 went down. Are they really plausible or are we're doing our best to distract our minds from the scary picture of startled pilots shedding the most elementary pilot skills and trying to climb away from something only they could see and force their aeroplanes where they were absolutely incapable of going?
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Old 16th Aug 2011, 01:16
  #56 (permalink)  
 
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So then, to no one in particular. I will assume in the absence of response, that "He Instantly Pitched up to 15 degrees" is not correct. The a/c did not, and no one short of Nostradamus can say what the PF Wanted.

The stick was positioned aft. To assume the PF wanted other than to arrest a Nose Down (0degrees, less than level, in stable cruise) is conjecture, let alone a "command to 15 degrees".

Since everyone "Cannot for the life of me understand the PF'actions", one may ask how then they can be reported?

"The climb is not understrood". Fine. Absent volition, then, how is it one can proclaim an opinion?

There is a careering from one stop to the other here of logic, and the upshot is that PF gets painted with the fools brush.

At the very least, it is unknown, if not ill-considered, whether the aft stick was intended at all.

So we are pleased, then, that the thrust of the thread has moved onto "human factors".

Not in evidence, and dare I say, Pompous. Also dismissive.

The record is cherry picked, parsed, and incomplete, which makes it not only unreliable, but in opposition to any conclusion.
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Old 16th Aug 2011, 02:45
  #57 (permalink)  
 
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Nostradamus wouldn't have pitched up 15 degrees if they had airplanes then. Most pilots would have pitched up 2.5 degrees and used about 85%N1. This guy was out of control.
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Old 16th Aug 2011, 02:53
  #58 (permalink)  
 
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I'll defer to your confidence, then. Bub, where are the Rudder tracks? I am not successful to enter the BEA website.

Cap in hands, can some kind soul post the Rudder traces?

Most thankful, Humbly
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Old 16th Aug 2011, 11:20
  #59 (permalink)  
 
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Control traces:

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Old 16th Aug 2011, 11:31
  #60 (permalink)  
 
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Lyman et al

I too had big trouble trying to get into the BEA site using Internet Explorer. Certainly no way to open their big report files.

In desperation I downloaded Google Chrome and can now get into the site. It's still a bit slow but it works.
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