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AF 447 Search to resume (part2)

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AF 447 Search to resume (part2)

Old 15th May 2011, 03:25
  #1381 (permalink)  
 
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Dangers of multitasking

Machinbird,

It can be heck to get old
And quite dangerous when you still try to do "multitasking".
Actually i am in parallel thinking how to conduct a "critical mission" by May end.
I saved my life some times doing "triple check" in some critical moments.
More experienced i normally double check non critical issues.
This (serious imo) error i detected in the first check. Actually i guess during the time you were asking me for the confirmation.

About this a learned a nice one:
Don´t be in a hurry. But don´t loose time.
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Old 15th May 2011, 03:53
  #1382 (permalink)  
 
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"CFIS" x CFIT

Hi,

It seems to me at water is easier to analyze the damage to the many parts. No trees, no elevations, just waves. And the parts remain clean, "washed".
ITOH no "terrain trail". In seabed has not "fidelity" at this depth.

Question:

The high sea waves "config" at impact moment is an important factor for parts damage and crash dynamics? Quite probable "rough seas" at estimated crash location? What kind of waves in ft?

Another consideration: When you crash with same trajectory and heading the destruction is less than at 90 deg.

Always assuming not so high horizontal speed. Let´s say, under 100 KTS

Last edited by Jetdriver; 15th May 2011 at 04:50.
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Old 15th May 2011, 04:06
  #1383 (permalink)  
 
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Pitot heater max. power in 330/340

Hi,

How many watts maximum? 115V?
Just increase the power would shorten the "unreliable indications"?
What kind of factor could limit the maximum power to be applied?
The mentioned power "modulator" reads TAT?

For certain conditions why not to apply "extreme power"? What kind of limitation to do that?

270 W

Last edited by Jetdriver; 15th May 2011 at 04:51.
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Old 15th May 2011, 04:15
  #1384 (permalink)  
 
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Hi Machinbird,
Originally Posted by Machinbird
I fully agree with your analysis as to how the ADRs were rejected on the Perpignan A320. It means that it would be harder to reject 3 ADRs of equivalent validity on AF447 by virtue of deep stall angle of attack, but still not impossible or even unlikely. I suspect the rejection mechanism would be primarily ram air impingement into the static ports.
I'm really curious to read your full explanation with such a "deep stalled" projected AoA achieved in normal law inside her full envelope protection; those ram air impingement into static ports able to trigger ADRs rejection without impacting her engine's air flow; explaining also this attitude at impact while she is still in a "deep stalled" and clean configuration; and the whole sequence lasting five minutes of descent from a very early upset before 0210.

Quite curious so.
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Old 15th May 2011, 06:35
  #1385 (permalink)  
 
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Hi Takata,
At this point there appear to be two paths to take an Airbus with properly operating computers in Normal Law outside normal flight limits. One path involves bad airspeed data leading the computers astray, but also implys that the RTL position would be different than that found on AF447's VS.

The second path can start with properly functioning airspeed and still lose control. It relates to factors that take control of the aircraft away from the computers.

Do you do any test flying? Take a look at the Gripen accident I am posting a link to. You only need to watch the first run-through. Do you understand the cause? (And I have posted this link previously)
YouTube - Saab JAS39 Gripen Crash 1993
You can read a translated summary of the accident here: Summary of report on JAS 39 Gripen crash on Aug 8:th 1993 in Stockholm
It appears that the original full accident report is not online.

I am not promising you that this is THE cause for the loss of AF447. The data gained from the FDRs will (hopefully) tell us what really happened, and it could be stranger still. This type of pathway to loss of control would tend to cause the aircraft to depart in an oscillating (or dynamic) manner. (More to post on the subject later)

Last edited by Machinbird; 15th May 2011 at 18:51. Reason: Correct an aircraft naming problem& add a reference
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Old 15th May 2011, 06:40
  #1386 (permalink)  
 
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Originally Posted by RR_NDB View Post
Hi,

How many watts maximum? 115V?
Just increase the power would shorten the "unreliable indications"?
What kind of factor could limit the maximum power to be applied?
The mentioned power "modulator" reads TAT?

For certain conditions why not to apply "extreme power"? What kind of limitation to do that?

270 W
The A300 FCOM mentions 28VDC and 320W, but the actual power deliverable will not be constant. The probe heaters are made out of resistance wire, the actual resistance changes with temperature, so monitoring the current gives an indication of the heater coil temperature. In other applications such as process industries handling flammable materials self limiting heat tracing tapes are used exploiting this effect.

For what power - consider a bench soldering iron - 12W can be used without any control to limit tip to about 200degC. 60W irons need temperature control - can only use higher power when soldering big things. Instant heat guns 100W will heat tip to red-heat in a few seconds. I'm sure you don't want the pitot tube more than 60degC on the ground, but its very important that you can check the heating - design case for heating and drain holes will be take-off clinb in bad weather.
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Old 15th May 2011, 07:53
  #1387 (permalink)  
 
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"CFIS" v CFIT

The high sea waves "config" at impact moment is an important factor for parts damage and crash dynamics? Quite probable "rough seas" at estimated crash location? What kind of waves in ft?

Rough seas (wave height) will have some influence, but depends on alignment of aircraft fuselage relative to wave direction.

Vertical scenario: Across wave crest will provide some small mitigation (dependant on wave height) of damage due to minimising contact area at initial contact and effect of momentary trapped air, whereas Parallel to waves will have minimal or zero effect.

Ditching type scenario: Across wave worse case for damage, and is likely to create multiple impacts (bounce). Parallel to waves is best case and offers best chance of survival.

Another consideration: When you crash with same trajectory and heading the destruction is less than at 90 deg. Always assuming not so high horizontal speed. Let´s say, under 100 KTS
Best way to answer that question is the view the tests at Langley:

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Old 15th May 2011, 09:11
  #1388 (permalink)  
PJ2
 
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Machinbird;
"Who was flying?" would have to be one of the key questions that the accident investigation would have to settle.
Here, I will speculate based upon experience in long-haul flights on the Atlantic and Pacific including the ITCZ.

Machinbird, CONF iture, Chris, I know you and perhaps others reading this, will be familiar with the following but some may not be.

In my experience it was more often the case that the captain flew the first leg and the first officer flew the next leg, etc.

If rostering, (especially for short-haul domestic), was such that a captain and first officer were assigned flights together for the month, the captain could change the pattern so that the first officer started the day and the captain took the next leg. (Perhaps some here can recall 80+ entries into the same darn airport in the same month...)

With the introduction of a relief pilot (for those not familiar...the RP is checked on the airplane, but not licensed for flight below cruise altitude), for long-haul work, the rostering process changed slightly. There are different ways to roster crews, and they have been discussed here before.

In the way to which I was accustomed, the captain, in consultation with the crew, assigned the crew rest rostering for the flight. There were no formal rules regarding rests, who was first, second, etc - it was left up to the crew. In our arrangement, the captain had first choice and it would go from there. If someone was really needing a break, (lousy sleep, noisy room, a dozen other reasons, etc) then that crew member could be offered first choice.

A second way, with which I am not familiar, would be laid out in airline policy and/or SOPs which the crew must follow, (with possibilities for variations of circumstance). Others can detail such procedures but I have the impression that it is more formally addressed at AF and the breaks will be taken as assigned.

There are benefits and problems with either procedure. I'm not going to detail them here.

Without intending anything other than conveying how we conducted rostering, I was up front during any ITCZ transition unless I knew the weather over the 3hr-or-so transit was benign.

If I flew the first leg, the next leg would be the first officer's. When on break, the relief pilot would occupy the left seat and the first offficer would fly from the right seat. When the first officer was on break, the RP would occupy the right seat and continue the duties of the first officer, whether flying or communications.

The RP was legally required to be on the flight deck from taxi to top-of-climb, at which time s/he would change with the first to go back for a break. For us, the rostering was discussed during the climb and times assigned for return-from-break, with a way to signal the pilot who would either be in the bunk just behind the cockpit or in a Business-class seat in a "tent" arrangement, that it was time to return to the cockpit. It was usually a 10-minute or so call to provide time to change and to wake up and possibly arrange a meal to be brought up when settled in the seat again. We often hung around the galley for these few minutes both going to and coming from break, just chatting with the galley folks and a passenger or two.

The A340 bunk was noisy and cramped. Compared to the B777, it was unacceptable. The A330 I'm familiar with had a "tent" arrangement and other than the mild discomfort of preparing for rest and arising after in reduced privacy, it was sufficient as the seat would go just about flat.

Determining breaks was straightforward. A half-hour would be added to the wheels-up time for top-of-ciimb time and the same amount subtracted from arrival time. The remaining time (essentially the cruise flight time) would be divided, almost always equally, between the three, or sometimes four crew members. If four, two would go back together.

On a ten hour flight, there would be about nine hours to divide between the pilots.

This is because first break would begin at top-of-climb, about a half-hour out and, in the case above, (3hrs each) would give about two-and-a-half hours of rest plus a bit of time in the galley area behind the cockpit, as described above. It isn't a good idea to get into deep (REM) sleep but it was also hard to avoid - one certainly wanted to avoid deep sleep, waking up just before top-of-descent.

Before crew-change point, a formal briefing would be conducted by the crew, for the crew member returning from break. Position, altitudes, pending clearances, any weather, fuel state, aircraft performance, communications...(which ATC was next to be called), etc and the seat change would occur. The last crew member on break would normally be brought up a bit earlier to ensure wakefulness for the descent, approach and landing.

With locked-cockpit doors, entry was formal and accomplished through secure procedures.

In the case of AF447, I think the captain probably flew down to Rio. In fact, who flew down might already be known through informal discussion with others who may have interacted with the crew on the layover or in dispatch the next day.

If the captain flew the leg down, that means that the first officer would likely be flying the trip home.

I have always interpreted the finding of the captain's body, as evidence, (not incontrovertible of course) that he was either in the galley area or in a business class (double) seat. I am unsure if AF's A330's have a bunk. If not, the business-class crew rest seat is the other cockpit crew-rest location; someone mentioned that cockpit crew do not use the F/A crew rest facility and they are correct. It is downstairs, mid-section of the aircraft and an unacceptable distance from the cockpit should a crew member's presence be urgently required.

If the captain was in the cabin then the RP would be in the left seat. He would be doing the communications work and flight plan log-keeping.

The pilot flying engages the autopilot associated with his seat position...left seat or right. If the first officer flies, the #2 autopilot is engaged. The #2 MCDU is the "master" and the #1 the slave, each associated with its respective FMGEC which becomes "master" or "slave"; #3 MCDU is used for ACARS, ATSU, AOC and ACMS communications and aircraft "health" functions.

The flying pilot can be thus determined by which autopilot was engaged - it would be rare for the "offside" autopilot to be used, especially here as there were no snags preventing use of both APs.

This is a bit long, but the actual crew-rest/break process hasn't really been discussed I believe, and perhaps it would help understand some things.

Last edited by PJ2; 15th May 2011 at 09:26. Reason: clarifications, grammar
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Old 15th May 2011, 11:43
  #1389 (permalink)  
 
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takata, remember when you are training with the aircraft instruments that this is not a whole lot different in concept than walking. You use organic instruments to assure your position, attitude, and direction. This includes eyes, ears, semi-circular canals, and proprioception. If it's dead black, say inside a closed room in a power failure, you still have the other senses. You can even get down to proprioception, the sense of your own body's position, you can still walk and get yourself to the door.

Proprioception is demonstrated by closing your eyes and alternately bringing your index fingers to your nose. It is also your sense of the pressure on the various parts of your feet when you are standing. When trained up it is a marvelous instrument most don't know they have. Are the plane's instruments all that much different aside from the lack of a direct nerve connection? You should be able to learn them so well they are a part of you as much as your feet are a part of you.

Sermon ended.
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Old 15th May 2011, 11:47
  #1390 (permalink)  
 
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bearfoil, computer science and abilities have reached a point where we're starting to ask how big does the computer that exercises judgement need to be. Remember IBM's computer's recent win on Jeopardy over past Jeopardy champions.

I figure by the time I die computers may be making organic intelligence irrelevant. Then we really WILL learn if androids dream of electric sheep.

By the way, you are dead on about too much autopilot. If there are going to be pilots at all they should fly the plane much of the time lest they lose their connection with the machine as part of their body. When they lose that, what good is it to have pilots at all?
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Old 15th May 2011, 12:22
  #1391 (permalink)  
 
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RR NDB, Machinbird and others -

Perhaps it is an OPE (Other Pilot's Eyes) problem that keeps it from being deployed? Or maybe it is deployed on military aircraft with some critical part of the technology remaining top secret.
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Old 15th May 2011, 12:56
  #1392 (permalink)  

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PJ2 :
Before crew-change point, a formal briefing would be conducted by the crew, for the crew member returning from break. Position, altitudes, pending clearances, any weather, fuel state, aircraft performance, communications...(which ATC was next to be called), etc and the seat change would occur. The last crew member on break would normally be brought up a bit earlier to ensure wakefulness for the descent, approach and landing.
I personally raised that pointa long time ago but it got lost in the multiple waves of speculations then:
There is no SOP for determining the rest periods of the technical crew during the flight, but there is a very strong tradition established.
As PJ2 said, take out the climb and descent times, divide by three the remaining flight time, et voilà!
For AF447, they took off at 22:29 Z for a planned flight time of 10:34 hrs.
Simplified to the nearest ten, that's
- a T/O at 22:30 z
- a landing at 09:00 z
- The rest period of each pilot will be 10:30 - 1 = 9:30 : 3 = 3:10 hrs.
- They 'd then had crew changes at :
TOC + 3:10 = 23:00 z + 3:10 = 02:10 z : first crew change, and
02:10 z + 3:10 = 05:20 : second crew change.
The three pilots will be again together at 08:30 z TOD for a touch-down at 09:00 z.
Among the CRM / Human factors that the investigators are going to concentrate on, a few seem quite important :
- The accident happened very soon after the crew relief, at one of the worst times for vigilance...
- The AF procedures don't allow LHS qualifications for the F/Os.
That means that the captain must be at his LHS for T/O and LDG. Which makes him take in 99% of the flights the middle slot.The fact that his body was recovered, and not the other two seem to confirm that fact.
- In all certainty, the operation of this flight was performed by a senior F/O seating on the RHS with command functions and a junior F/O seating on the LHS with basic radio-com and navigation duties, along with some minor engineering duties.
IMVHO, we are very far from an optimum use of the flight deck crew's capability as the PF/PM duties are made difficult because of that task distribution : ECAM actions from the LHS are not that obvious and in many cases, there is a risk for the RHS pilot to lose his main flight instrument panels.
- Still IMVHO, the risk of locking the captain out of the flight deck, for security reasons is immense. Maybe there's a way around it.
- Finally, there is the question about severe weather or not ; in this partial scenario, of course the captain wouldn't have left his seat had there been a mearest risk of hitting one.

Just my two Euro cents
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Old 15th May 2011, 13:53
  #1393 (permalink)  
 
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So, if the Captain wouldn't have left his seat if there was a hint of bad weather.
But he had left his seat.
The a/c didn't deviate like others.
Weather radar issue then?
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Old 15th May 2011, 14:39
  #1394 (permalink)  
 
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2 weather-related aspects which I see might need further look into:

First of All, those excellent meteo-drawings by Tim Vasquez imply that the crew should have had (probably) a similar picture on their radar scope and probably failed to interpret correctly and thus did not avoid what should have been avoided. Even Tim Vasquez writes, that the depiction in the cockpit might have been completely different. If there was no water in liquid state present, the actual picture might have suggested that there was no danger in penetrating the weather ahead (green depiction, or even nothing).

On the other hand, the potential of ice crystals seem to have been underestimated in the past, as recent discussions reveal. There are some excellent presentations around which show the effects of ice crystals on engines or other airplane surfaces, see for example here. One might even suppose that engine thrust might have been lost or limited in addition to the failed probes, adding up to the dire situation of the crew.
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Old 15th May 2011, 14:48
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PJ2, re "RP".

AFAIK, AF doesn’t use "Relief pilots" per se. Long haul F/Os are always ATPL licensed, fully type and line qualified. The captain selects the F/O in charge during his rest period, usually the most senior (they often have equivalent seniority). This F/O is to take the RH seat.

Mr Optimistic, re "The a/c didn't deviate like others"

No two a/c deviated identically that night. Storm cells have a tendency to move. There may be a radar issue though, just as anything else.
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Old 15th May 2011, 15:08
  #1396 (permalink)  

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DJ77,
AFAIK, AF doesn’t use "Relief pilots" per se. Long haul F/Os are always ATPL licensed, fully type and line qualified.
Not nearly always :
1.5.1.3 Copilote
Homme, 32 ans
ˆˆ Licence FCL de pilote professionnel (CPL) obtenue le 23 avril 2001
ˆˆ Qualification de vol aux instruments multi-moteur (IR ME) obtenue le
16 octobre 2001
ˆˆ ATPL théorique obtenu en septembre 2000

From interim report # 1.
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Old 15th May 2011, 16:46
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DJ77. Thank you. True but all a puzzle, seems there isn't one aspect one can be sure about. Cabin unsecured - hardly consistent with the meteo analysis by TV but consistent with Capt taking his rest and FA on their feet. Must have been unexpected and sudden and not on exit from anvil which would otherwise have had a lumpy ride first.
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Old 15th May 2011, 17:50
  #1398 (permalink)  
 
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Lemurian, thank you, I stand corrected about the ATPL licence.

Mr Optimistic, I agree FA not seated is puzzling. They would have taken their seats, or any passenger seat available depending on where they were in case of severe turbulence, wouldn't they ?
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Old 15th May 2011, 18:19
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Hi JD-EE,
Originally Posted by JD-EE
takata, remember when you are training with the aircraft instruments that this is not a whole lot different in concept than walking. You use organic instruments to assure your position, attitude, and direction. [...] You should be able to learn them so well they are a part of you as much as your feet are a part of you.

Sermon ended.
Thank you for your kind sermon, my sister.
:-)
Nonetheless, I'm sticking with my point that human beings could similarly be fooled by their own senses like a computer by its own probes. ie. human spatial disorientation may be compared with a computer voting one good ADR out because two ADRs are displaying coherent but wrong data.
Human factor is not proved to be the panacea at all, only by itself, neither is automatisms. In some way, reaching a high level of fluid teamwork with the machine (ergonomy) is theoretically the best way to get the best performance out of each, mostly by correcting the worst issues that may be caused by each independently.
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Old 15th May 2011, 18:22
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Originally Posted by DJ77
Mr Optimistic, I agree FA not seated is puzzling. They would have taken their seats, or any passenger seat available depending on where they were in case of severe turbulence, wouldn't they
Why would you not allow them to rest a bit, as the flying crew, during such a long night flight?
There is still this FA resting module below the main deck.
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