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AF 447 Search to resume

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AF 447 Search to resume

Old 3rd Nov 2010, 19:41
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bearfoil,

Interestingly, the type of discussion you allude to (with a very experienced A330 pilot) was one of the prime reasons I decided to post what I did. I suppose I'm looking for additions, contradictions, clarifications from whomever has knowledge or experience (either operationally or technically) with that aircraft and or similar aircraft with the same or similar sensors, instruments, and/or software.

Diversification,

Interesting points. Especially tantalising (for me at least) is your comment:
It is a pity that we don't have access to the source codes used nor program flow-sheets
And I may have missed it, but I don't recall reading previously about the content (and timeline) of the FAA's AD2008-17-12.

grizz
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Old 3rd Nov 2010, 19:44
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grizzled;

Re yr qu.#2: You really need flight test data to answer that question, i.e. to compare the pressure errors as a function of AoA and SSA to the 'fault' thresholds of ADIRU's and PRIM's. My intuition tells me that static pressure sources would be affected sooner (at smaller angles) than pitots. The next problem of course is to find a reason for the unusual attitude.

diversification;

Although perhaps of minor importance for what you have written, you may want to look up ATSB's report on QF72 for AoA. IIRC the difference is that if all three values are valid, the PRIM's take the average of AoA 1 &2, whereas they take the median for other air data sensors.

regards,
HN39
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Old 3rd Nov 2010, 20:24
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Pitot Disagree

For what it's worth, pitot disagree ramifications have been discussed quite a bit... my own post back in June touched on this issue as well...

There are 543 posts in the AF447 threads with the word "pitot" in them; 86 of these posts also include the word "disagree." The trick is to distill probabilities from the many possibilities using good engineering, science, and a pilot's common sense. Any more volunteers for the distillery work? Send me a PM.

GB
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Old 3rd Nov 2010, 22:28
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GB...

Point well taken. I'll send you a note so you can give me my homework assignment...
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Old 3rd Nov 2010, 23:53
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HN39

Maybe my wording was not explicit and clear enough regarding two AoA:s. It read "When only two AoA:s are in use, their average is said to always be used." By in use I meant being used by the system or present on the aircraft..

Grizzled
There was a very long thread about AF447 also on Airliners.net. Some of the hypotheses offered there may be worth to include in the sifting of the content in the corresponding threads here.

You can begin with this link and follow it backwards and forward:

AF A332 Crash (F-GZCP) - Part 18 Civil Aviation Forum | Airliners.net

Regards
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Old 4th Nov 2010, 09:20
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Diversification;

You wrote:
In case there are three AoA units their data are treated in the same way.
The ATSB wrote:
In addition, for ADIRU parameters except for AOA, when all three values were valid, the median value was used for calculating the flight control commands.
And in the next paragraph:
There was a potential for the AOA sensors on the right side of the aircraft (AOA 2 and AOA 3) to provide different values to the AOA sensor on the left side of the aircraft (AOA 1) in some situations due to aircraft sideslip. In order to minimise the potential effect of this difference, the PRIMs used different processes for AOA compared with other parameters when determining the value to use for calculating flight control commands. More specifically,...
regards,
HN39
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Old 4th Nov 2010, 09:28
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mm43, I was merely opening up the range. I misread your comment, I suppose. I'd expect there were more planes within a 400 mile range if the route really is that busy.
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Old 4th Nov 2010, 13:36
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bearfoil: evry plane was trucking along in its own little world
how much bigger would be the crash-risk if on fly in smal pakets over the atlantic with two planes along one flightpath, with a normal distance maybe 25NM and VHF contakt (plane-plane) and view on TCAS ??? (and than following a bit longer distanc to the next flight)

and not one by one with a rhythm of more than ten minutes

grity
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Old 4th Nov 2010, 18:17
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JD-EE
I'd expect there were more planes within a 400 mile range if the route really is that busy.
Yes, there were, but as Bearfoil had previously made a comment about French reluctance to admit something wasn't right, I had selected the 3 Air France aircraft. Made easier by the BEA having created the basic graphic.:-)

mm43
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Old 4th Nov 2010, 22:31
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Regarding the missing communication:
This may be an indication that something went wrong much earlier than initially thought.
But it doesn't have to.
When looking at NTSB accident reports (mostly GA planes admittedly) you will notice that in a very high number of cases if not even the majority of fatal accidents no distress calls were made by the pilots.
Especially in those cases where the pilots are fighting the plane hoping to be able to save it very often the comms remain silent.
Only when they realise there is nothing more to do e.g. shedding a wing or the rotor (in case of a helicopter) the percentage of distress calls appears to rise again.

So if a critical situation developped very rapidly out of the blue, it wouldn't be so much out of the ordinary if no radio transmissions were made, especially so far out over the ocean.
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Old 5th Nov 2010, 00:02
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Henra,

Yes, of course!
First manage the airplane.
In the dark night ...

But sometimes, it occured electrical power failure:
DC ESS bus out of duty,
DC bus 1 out ouf duty,
DC bus 2 our ouf duty,
AC bus ?

Perhaps like this ? (see second part beginning at "The electrical system on an Airbus A320 consists of ...").
I have to find NTSB report link (5 minutes total electric PAN on United flight ?).
No, I think it was't United, but perhaps european flight; please, wait till tomorrow.

Regards
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Old 5th Nov 2010, 00:34
  #2372 (permalink)  
 
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AF447 Data Mining

By way of update, we have combined the PPRuNe and Airliners.net threads into a single database consisting of the two PPRuNe threads of 4583 posts and the Airliners.net threads (about 25 of them) of 6437 posts for a total of 11,020 posts.

Still looking for more many-eyed volunteers to help with development of the decision tree logics and classifying these documents.

GB
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Old 5th Nov 2010, 10:40
  #2373 (permalink)  
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henra

Common sense, really. Two basic considerations re: 121.5. The equipment was serviceable, and the pilots were otherwise engaged, or the equipment was down. Emergency "Call" in this case gains the crew what? Why does this a/c rely on an automatic beacon at impact? Shortsighted? What got missed by the architects of the Comm system such that the beacon was not activated automatically in the flight regime? Direct Law at cruise and 35k feet? A position report immediately to Mx base, that continues until impact needn't take up any of the crew's time, just as ACARS was the bearer of bad news about systems, why was ELT not Satellited to base? Money? Or was it?

The communicative aspects of the accident need a look, but it isn't just the radios that are important here. Weather Brief, The conversation Captain DuBois had with the Iberia crew, the inter station gab ATLANTICO/DAKAR, The Lufthansa flight, AF base ops, etc. The folder is quite large. Most accident reports include sufficient data for a conclusion regarding the accident, subject to the data recovered, but miss a gold mine of Industry introspection that may be of even more benefit to the Public and the carriers. The reason? Private enterprise, when in Public Carriage, is a special beast.

It needs to start with detoxifying the "Proprietary" position of the Principals.

In a corporate culture that values honesty and mission orientation, there is a benefit in safety. Financial loss and degraded market share considerations have gotten so rabid that they are starting to kill us.

The format must start migrating to an open and public spirited goal, rather than a secretive and defensive "Hold the Line" exercise. Not an easy accomplishment in an environment of declining gross seat numbers, storage of a/c, and fear.

Best of luck to Great Bear.

bear
 
Old 7th Nov 2010, 07:27
  #2374 (permalink)  
 
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To be fair, bearfoil, there is one more consideration I'd hoped a pilot would chime in and talk about. 121.5 MHz is an emergency frequency. Using it for idle chit-chat is or should be quite a downer to one's career. However, my reading of being out of communications is that it's a minor emergency sufficient (barely) to qualify for use of that frequency.

I hope somebody "real" chimes in on this proposed use of the emergency frequency if it's inappropriate use. (And it arguably is more appropriate after this example of what can happen when one is out of communications; but, could be.)
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Old 7th Nov 2010, 12:34
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121.5 was createed for and is used for aircraft (or ATC) distress or emergency communication. It is a guard frequency monitored by all aircraft while in flight, ground stationns, and military, and is not used for general communication. Any communication other than emergency is switched to other appropriated frequencies.

Edit: Perhaps I was too short with my reply. If one has an emergency, or has a situation which requires contact with the ground, or another airplane, and cannot communicate using normal and/or other channels, then the use of 121.5 is a valid option. Safety to yourself, as well as others, defines the principle. I would never split hairs shoud the need arise.

Last edited by wes_wall; 7th Nov 2010 at 14:53.
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Old 10th Nov 2010, 11:35
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As we're all taught, communication is last in the order of priorities for a pilot to manage in an emergency:
"Aviate, Navigate, Communicate."
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Old 10th Nov 2010, 11:58
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JD-EE

I see where your confusion arises relative to my post. I mention "Other Communications", as: Wx brief (prelaunch), Inter line gab: (Prelaunch), Crew brief,
( Prelaunch). These are verbal comms, not related to 121.5 Did you think I meant these other discussions as Emergency Freq "ballast".?

My Certificate does not say "Pilot". Strictly speaking I am not a Pilot, I am an Airman.
Airman Certificate, January 12, 1971. So I am also old!! Old, and Real!

I think there is a possibility to highlight a possible inadequacy in emergency procedures here. With two (?) ELT, one auto and one manual, some questions.

Manual.

1. requires pilot awareness.
2. requires pilot volition, a place in the workload.

Auto

1. Transmits at "g" loading related to impact.
2. Involuntary

My question stands, if the pilots are incapacitated, the aircraft does not transmit ELT until impact?

So enhance the ELT to expand its trigger to Unusual attitudes, manoevering loads, etc. an Early warning of emergency. and not limited to just Impact. How about "Direct Law" at cruise, with UAS? Surely no one was casually testing Law response or Protections that fateful night? Equipment that is not utilized and optimized is too expensive, there is no saving money in an Emergency. What would prevent an augmentation of ELT? Fear of criticism? Fear of "having missed something"? If the pilots were mode confused, and doomed, at least Ops could start the ball rolling sooner, rather than Later.

How difficult is it to add some automatic reporting of Computer sensed crisis?

Could it piggy back on ACARS? Evidently ACARS was missed in this case; an attentive monitoring of all the ACARS would have elicited a secondary report of crisis. So if ELT is transmitted by Satellite, a loud alarm at the Base? Sufficient to awaken the monitor? Or bypass the Mx and relay the ELT immediately to Ops?

This could be the beginning of a new relationship twixt The Computers and the Pilots. Emergency alarm would be Automatic, and does not depend on Pride or Ego, that satisfies the AB wonks, and it would let the crew off the hook if they waited "too long"?

EACARS ??

Kashoggi: (sorry about the missed lease payments, it has been a tough year!)

cheers, bear

Last edited by bearfoil; 10th Nov 2010 at 15:55.
 
Old 10th Nov 2010, 15:25
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Bearfoil +1

EARS - Emergency Automatic Reporting System
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Old 11th Nov 2010, 04:05
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Bearfoil (and others), I simply figured that before things pickled it would be a priority for the plane to obtain contact with DAKAR. That way they'd be informed of traffic if conditions changed. DAKAR would not move another plane into their place in the flight path. And possible wx briefings could be passed. And I wanted to amplify that I figured 121.5 was hardly for idle chit-chat. and that I saw reestablishing contact with DAKAR "might" be considered "idle chit-chat."

121.5 is a facility the pilots would have available. And before things pickled there was a small chance having that communications might have saved a large number of lives

(And, it seems you've flown something somewhat more rugged than the modern flying luxury sedans. {^_-} I'm NOT a pilot so there are lacunae in my knowledge base that I'm admitting and in a way begging for both forgiveness and having said gaps filled. I have an active curiosity and love of learning - what I want to learn And I admit to preferring "having learned" over the learning process itself.)

I am also not talking about the ELTs. I'm talking about dialing in 121.5 (or otherwise selecting the frequency) and politely asking for some minor assistance.

Once things pickled I can understand no transmissions. And probably by the time they might have thought of 121.5 just to warn other aircraft they were coming into their paths, perhaps, they were below common flight levels for that path. So "why call" unless there was a desire to let maybe might be rescuers have a clue where they were.

My 121.5 interest is chiefly in the interval from the time of handoff by Atlantico and failure of DAKAR to respond to the time the flight pickled. I am presuming that during that interval 121.5 is a facility I'm surprised was not used. however briefly specifically for establishing contact with DAKAR via a relay through another plane in their "immediate" area. Planes within 400 miles of they surely should have heard them if they transmitted.

With regards to piggybacking a computer detected major fault (erm such as auto-pilot kicking out?) through ACARS is germaine to future instances like this. It might reduce some of the mystery, especially if it moved into a PR every minute instead of every 10 minutes. It didn't shift to a new reporting mode. But it did report the AP kicking out, and nobody knew this until well after the disaster had taken place. Apparently ACARS is not monitored in real time by any body or thing "interested" enough to have done anything.

I see three distinct interesting intellectual pursuits from this disaster, why and how did it happen, what could be done to prevent the mystery next time, and of critical interest what could be done to prevent it happening again? All three answers are tied to "what in tarnation happened to that flying composite over powered hypertrophied cigar? And I'm not willing to accept the simple answer that the data suggests, so far - that God swatted the plane out of the air for some reason. But it surely looks like the plane was subjected to a high G change in velocity followed by a fall from 35000 feet followed by an unfortunate meeting with the Atlantic Ocean. (Or else things pickled earlier than we think at this time and the slight "off track" last GPS report shows it.)

I feel as though I an trying to add two and two to make three. The sum seems to be less than the known parts. Of course, that means there must be another part por parts to consider. So far the suggested parts add up to oddball values of four when the known parts are examined.

{o.o}
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Old 11th Nov 2010, 05:58
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Cool

Hi,

I posted in the past some messages about those ELT in the aircraft and their unitility cause the configuration.
More efficient would to put a monkey with a parachute and life jacket, EPIRB, and a supply of bananas.
This monkey is also provided with a spring and would be ejected if the aircraft is at an altitude of 1000 feet and if this altitude so this does not correspond to that of the flight plan.
After recovered and after few more bananas ... he will explain everything.
I know ... animals lovers will not appreciate
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