AF 447 Search to resume

[mm43]

BEA - Press release - 2 April 2010

Flight AF 447 on 1st June 2009
A330-203, registered F-GZCP

Information, 2 April 2010

The « Anne Candies » this morning joined the « Seabed Worker », which arrived in the search zone yesterday.

The undersea searches have begun. Further information on these will be released before the end of next week.
-----------------------
EDIT :: Forecast for period from 2010-04-03 1200z to 2010-04-06 0600z is:-
Wind (10m) - 10KT/090T becoming 10KT/060T
Sea/Swell - 1.5m/020T, Period 9 secs becoming 1.5m/060T

mm43

[Bobman84]

Are there any further updates on the search progress?

[GreatBear]

There be Dragons Here

At the edges of early sea charts, navigators occasionally discovered an ominous warning that "There be Dragons Here." These metaphorical Dragons are just what AF447 encountered in the dark of night last June. Many A/C follow similar courses along the edge of the coffin corner today, so it's critical that this tragic upset be fully understood.

Interest: 2,220,647 views and 4,587 posts -- that was the original AF447 thread archived at the turn of the year. In this newer thread, 132,561 views and already 662 posts.

Sadly, the last post on this thread was "Any news?"

It would seem that the agencies in control and the primary stakeholders -- those paying for the search vessels and the analysis of data -- are uninterested in a pro-active and open information exchange. Bad PR, in the age of T w i t t e r and Blogs. Bad PR, with implications of secrecy and orchestration. Bad PR, when the interest is so high and answers so important.

I'm not sure what activities make level-headed and smart PPRuNers angry, but I should think docile waiting for rare bowls of carefully conditioned information and being shut out of the ongoing big picture would be one of them. These agencies can't say "None of your business" because it is, indeed, your business! None of us wants to fly where there be Dragons.

Note about edit: When this was originally posted, PPRuNe software automatically converted the word "T-w-i-t-t-e-r" to the word "PPRuNe" and the sentence did not read properly... Mods, feel free to correct if the Twi---- word is a proscribed word...

[GobonaStick]

It would seem that the agencies in control and the primary stakeholders -- those paying for the search vessels and the analysis of data -- are uninterested in a pro-active and open information exchange.

I'm sure those paying for the search vessels would be happy to exchange information, if they had any to exchange.

From what I understand it's still lying four miles down at the bottom of the Atlantic.

[mm43]

The BEA have made it quite clear that they will be releasing further information on the progress of the search by the end of this week. That is a huge advance on what we had in the Phase 1 and 2 searches, and should be welcomed.

In the meantime, the weather in the search area is ideal, with a 1 - 1.5m / 10 second swell and 5 - 10 knot winds from the easterly quarter. CAV has no part to play in this operation!

mm43

[GreatBear]

4 Miles of Patience

Thanks GobonaStick for setting me straight. And mm43 for your continuing analysis and excellent briefs!

The BEA website does show increasing availability of information at the press release area along with some videos. Next info promised for later in the week. I suppose a 24/7 live web feed from a camera in the submersibles control room aboard the Anne Candies or Seabed Worker would be too much to ask and boring to most... Be nice to see a daily briefing with some granularity and detail, though. No doubt the entire affair, including the search details, will become more than one best-selling book, and official reports, recommendations, and new rules will be printed in many languages. Let me apologize for sharing my impatience.

[ChristiaanJ]

GreatBear,
Your frustration is comprehensible, and I'm sure it's shared.

But at this moment, I think GobonaStick's is the only valid answer

Trying to search four miles down in the ocean for the proverbial needle in the haystack is something very slow, difficult and laborious.
And even if you find something, you still have to go down there and make sure it's not another rock....

Do you really want some vague and unsubstantiated information, as happens only too often in the media, and even here on PPRuNe?

Let them get on with the job. They're only too well aware of how many people are interested in what they achieve.

CJ

[JD-EE]

CJ, your post triggered a thought that may be slightly off topic. I'm putting it out there so that somebody who is talented and in a position to riff on the idea and make it practical might see it.

It is hard to tell one object from another with sonar. It's not impossible. I wonder if it would be possible to build two permanently affixed nodes on the recorder packages that resonate at specific frequencies in a relationship of perhaps 1.7 to 1 in frequency.

I suspect that ratio would hold with pressure. And it would give you, in effect, a nice passive transmitter as part of the boxes. A chirp radar should be able to pick then out of most any other sonar returns that might happen.

If this is a good idea, I hope somebody takes it and runs. I'll shut up now.

{^_^}

[mm43]

BEA - Update: English subtitles to PR Video

The BEA have added a link to English subtitles text that matches the commentary on their previously released video of the Recife press conference.

http://www.bea.aero/en/enquetes/flig...es.navires.srt

This now confirms that the search area is between 2,000m^2 and 3,000m^2, and hopefully the next update will give some indication of the actual grid pattern they are using in the search, e.g. is the search being conducted along 350/170T degree lines matching the general line of the ridges and valleys.

mm43

[mm43]

BEA - Update: Departure Video

My previous post mentions the English subtitle text available for the PR video. In fact it is actually for the departure video which is available in mp4 format at:-

http://www.bea.aero/fr/enquetes/vol....es.navires.mp4

A Windows Media Player version is at:-

http://countjustonce.com/a330/depart...res_WMV_V8.wmv

This video is informative, and shows the equipment, along with some interesting views of the proposed search area. I will attempt to decipher some of those search area plots and post a graphic with more detail of the search area shortly.

The link in post #670 above, gives the English language text associated with the video.

mm43

[HazelNuts39]

QF72 AoA

EDIT:: The link to an image of the liftcoefficient-AoA-Mach relation derived from the QF72 upset FDR data has become invalid.
regards,
HN39

[mm43]

BEA - Update on search

Flight AF 447 on 1st june 2009
A330-203, registered F-GZCP

Update on sea searches on 7 April 2010

Since the sea searches began on 2 April:

o Orion, a towed sonar on board the « Anne Candies », has covered 600 km2;
o The three Remus autonomous underwater vehicles on board the « Seabed Worker » have made nine dives and covered an area of nearly 800 km2.

The meteorological situation in the zone has allowed the crews to work in good conditions.
-----------------------------

A graphic showing the progress of the search is at:-

http://www.bea.aero/en/enquetes/flig...7042010.en.jpg

This is a high resolution depiction of the search zone.

mm43

[Chris Scott]

QF72 AoA versus cL Graph

Thanks for that link, HN39.

Still getting my head round the detail of the graph but, in the light of the discussion some of us had (starting with #523/Mar16th & #537/Mar21st, and concluding here with #558/Mar23rd), it's interesting that they seem to have derived Alpha (AoA) from their stated equation:

" alpha = pitch - fpa "

We have already discussed the possible limitations of this presumption; specifically in rapidly moving air (vertically or horizontally).

I was under the impression that a direct reading of AoA would be recorded elsewhere; either on the DFDR or the QAR, or both; but don't have a list of their parameters to hand. AoA certainly used to be available in real time via the AIDS system on the A320, and it would be strange if that was not recorded and/or transmitted on ACARS. The fact that the QF72 recorders were, presumably, in pristine condition makes one wonder if they will do any better for AF447, when the DFDR is found? The QAR is unlikely to have survived intact.

Who produced the graph, I wonder?

Chris

[CONF iture]

You are correct Chris, AoA data (2 out of 3) were available in the Interim Report on the A320 XL Airways accident in Perpignan.

[HazelNuts39]

QF72 AoA versus cL graph

Chris Scott;
thanks for replying, I’m pleased someone is interested in my little exercise.

Originally Posted by Chris Scott; #674

it's interesting that they seem to have derived Alpha (AoA) from their stated equation:
" alpha = pitch - fpa "

The equation is correct as long as fpa is defined relative to the air mass. In this case: it is assumed that the airmass does not move vertically: sin(fpa)=vsi/TAS

I was under the impression that a direct reading of AoA would be recorded elsewhere; either on the DFDR or (...)

The DFDR traces in the ATSB report include AoA, but the scale chosen to show the ‘spikes’ is too small to read a real AoA value. Therefore I integrated vertical acceleration to obtain vsi, and from that AoA.

Who produced the graph, I wonder?

The graph was produced by MS EXCEL from data read manually from the DFDR traces provided in the ATSB 1st Interim Report on the accident, with some help from BOAC and PJ2.
regards,
HN39

[Chris Scott]

HazelNuts39's Graph of AoA versus cL for QF72

Quote from HazelNuts39:
"I’m pleased someone is interested in my little exercise.
... with some help from BOAC and PJ2."

You are too modest... I did wonder. But may I suggest it may be advisable to provide an attribution, in case someone assumes it is extracted from an official report?

Quote:"The DFDR traces in the ATSB report include AoA, but the scale chosen to show the ‘spikes’ is too small to read a real AoA value."

I see the problem, but would it still be worth superimposing the official AoA trace on your graph, for comparison purposes: uncorrected – and perhaps also corrected – by the Prandtl-Glauert "rule"?

Not having read the QF72 report in any detail, must admit I do not know if wind and/or vertical air-currents were a factor. In relation to AF447, however, there is every reason to suspect that horizontal and/or vertical gusts may have at least contributed to the aircraft departure.

Quote:
"In this case: it is assumed that the airmass does not move vertically: sin(fpa)=vsi/TAS "

In our earlier discussions, I think I was able to establish in #552/Mar23rd – if only qualitatively – that even a steady movement of the airmass (vertically and/or horizontally) leads to an error in the assumption that " alpha = pitch - fpa ". As for gusts, they are another matter.



Nevertheless, subject to the points above, your graph seems to be a very useful exercise – thanks.

And thank you, CONF iture, for the official graph of AoA for the XL Airways accident.

Chris

[HazelNuts39]

QF72 cL vs AoA graph

Chris Scott;

Originally Posted by Chris Scott

But may I suggest it may be advisable to provide an attribution, in case someone assumes it is extracted from an official report?
Quote:"The DFDR traces in the ATSB report include AoA, but the scale chosen to show the ‘spikes’ is too small to read a real AoA value."
I see the problem, but would it still be worth superimposing the official AoA trace on your graph, for comparison purposes: uncorrected – and perhaps also corrected – by the Prandtl-Glauert "rule"?

Thanks for both suggestions. I've added a note to the graph and the post.
Adding the 'official' AoA doesn't seem practical: The AoA trace is on figure B2, which has a different timescale from figure B4 that I used, and 10 degrees AoA is only 3 pixels.
regards,
HN39

[Chris Scott]

Quote from HN39:
The [QF72] AoA trace is on figure B2, which has a different timescale from figure B4 that I used, and 10 degrees AoA is only 3 pixels.

Sounds virtually useless. I take your point, and presume the investigators would have had access to a better one?

Chris

[CONF iture]

Originally Posted by HN39

Adding the 'official' AoA doesn't seem practical: The AoA trace is on figure B2, which has a different timescale from figure B4 that I used, and 10 degrees AoA is only 3 pixels.

On that matter, the XL Airways report is not different : The AoA traces are not made available to us in a readable and informative scale ... ?

[mm43]

BEA - Update: Search Operations Video

The BEA has released a new video in French showing operations in the search zone, and the mp4 version can be found at:-

http://www.bea.aero/fr/enquetes/vol....tionnelles.mp4

I'll add a link to a Windows Media version as soon as I have converted it to that format.

http://countjustonce.com/a330/first-...onal-dives.zip

Download the zip file, save and then double click on it. The file should then be converted into wmv format and will be ready to play.

mm43