Chris Scott,

I will analyze the HF antenna design of VC10, initial DC10 and the poor ones like in 767.

Will be a pleasure to do that.

Aft reception: When your antenna is at a/c tail you have a "ground plane to the front of it" making RX and TX much better than to the back of the a/c.

Just to brief you on the theory: if you drag a wire, bonded to fuselage, the aft sigs would be the same to the front. Better if the wire is quarter wavelenght of the operating QRG. In this case the antenna would be in the middle, symetrical (fuselage to the front and trailing wire to the back).

On St Elmo and static poor RX this could only be solved increasing the power out of ground station but unfortunately the days of the 12ACX and 4WTFA are gone. They are using lower power and this is an error. I will investigate the current power levels and antennas being used in DKR, REC and others.

I designed and used several antenna tuners and at certain QRG they simply don´t tune. (for a given antenna type). And frequently sparks due VERY HIGH voltage.

On trailing antennae see the one of E6 Tacamo:

Boeing: E-6 Tacamo - History

Trailing a wire roughly the same lenght of cruise FL, 30,000 ft.

The antenna is a dipole (end feed, similar to the one used in Zeppelin) and the radiating element is another wire, a short one. (~5,000 ft), feeded with a coil in the a/c antenna tuner.

The purpose for this is to put a signal to be received by a submarine. (E6 orbiting) in this case the dipole (horizontal) radiates to sea, sides an top of the a/c. For a ONE WAY comm to the sub. (Sub just in RX mode)

QRG around 17 KHz (under 20 KHz).

:)

Hi,

From not far from here (Internet is a small world :) )

Google Vertaling

Original:
« Deep trouble » pour le BEA

BJ-ENG

I think you are correct. Of the two decks, I think you are looking at the cargo floor (member). The Cargo floor, though shorter in span than the pax deck, also has 'bridging' to support the floor, while the pax deck is clear span. The piece of bridgework that remains attached to the floor member is relieved as the pic shows it would be. Also, there appears to be a remnant of fuselage frame remaining, so this piece would be located at the area where the cargo floor and fuselage mated. ??

Captain Scott

Last look I had at the 300 family, (A300) last August, there was a fourth pitot probe on the port side, is this a new addition? Is the A330 newly configured this way??

jcjeant

The Airbus cannot Stall, and it cannot come apart at altitude, So the BEA has reported as these truths imply: "Enligne de Vol" There is no need for looking directly under LKP, or within 40 nm for that matter. :uhoh:

HF slot antenna for the C130
 

JD-EE

At page 7 in the link below there is a good text on the issue.

Slot antenna

Thanks for the link jcjeant.

En ligne de vol ...

http://i25.servimg.com/u/f25/11/75/17/84/af447_10.png

For sure there has been AMS, but also Perpignan, and maybe AF447 ... ?
I find it peculiar Airbus is using a 737 profile to demonstrate the brand new procedure to survive a stall ...

DFDR found w/o memory module
 

Sans les Memoires??
 

No matter. What I want is to hear these two (or Three) pilots as they try to keep this heap in the air, after it has done its ignorant best to dive into the sea.

It will reclaim for them their heroism, and the shocking lack of dependability of this a/c on that date.

The wreckage is the key, and soon the lightbulbs will pop, as folks "piece" together how this happened.

Boxes optional.

There are two salient issues to remember, and these have not been addressed.

"There was NO evidence of forward momentum" (Horizontal, but 'backward'?)

What is MISSING from this "debris field"?? (Second engine? Wing parts?)

"Le chassis" (in the French text) may refer to the 'mounting rack', not to the FDR unit itself.
It's what I was afraid of... the recorder(s) being ripped from their mounting racks (not necessarily designed to the same crash-resistant standards as the recorders themselves), and making their own way to the sea bottom, and getting buried in the silt....
Good luck, guys...

Edit: Ignore, please. I've now seen the photos, and that's obviously the recorder unit, not the 'mounting rack'. Not sure whether the photos show the CVR or the FDR, though.

"Deep Trouble" for the BEA?
 

Quote from the piece referred to above by jcjeant (English translation of the original French):
"... BEA has never considered the possibility of "stalling".
…BEA has never contemplated that the A 330 could have come out of its flight. The BEA, however, only determined the search area according to the inverse hypothesis that "in view of the maximum possible speed of the aircraft, the wreckage of the plane had to be in a circle of 75 km radius (the circle) centered on the last reporting point position (LKP) "(Mr. TROADEC note of 8 April 2011).
"Deep trouble" for the BEA.

Only fair, I think, to point out the source of these accusations. It's a website called "Les Dossiers Noir du transport aérien" (Air Transport's Black Files), a "Blog citoyen d'un ancien commandant de bord" (Citizen's blog by a former airline captain).

One or two names spring to mind... As far as I'm aware, the accusations made are nonsense.

How can the writer say that the BEA has never contemplated stalling or departure from flight envelope ("sortir de son domaine de vol") ?

How can it be wrong for the BEA to define a circle of radius 75 km (40 nm) from the LKP as the search area? To my knowledge the BEA has never stated that the accident could not have taken place at or close to the LKP. (We still don't know where it happened, but that's another matter.) If they had defined and searched smaller circle, and the debris had turned out to be outside it, would that have led to another version of this conspiracy theory?

With the benefit of hindsight, the apparent failure to search closer to the LKP in Phase 3 looks unfortunate, but the difficult search seems to have been prioritised in the areas of highest probability. Eventually, the two search vessels (Anne Candies and Seabed Worker) simply ran out of time last year.

To accuse the BEA or any other organisation of deliberately ignoring the most likely site of the debris is preposterous. In any case, they would have known that the industry would never let them get away with it long-term. However frustrated the interested parties are with the delay in finding the main debris field, and however much we would all like to have unrestricted access to its progress, it seems to this amateur observer that the BEA is supplying a similar amount of information to that which has been disseminated in other investigations of comparable complexity.

Don't be silly, JAM. To draw such a diagram, you borrow from a generic database of shapes.
And not all aeronautical engineers are fervent 'spotters', you know?
To me, all them Coke cans with two engines look the same. Personally I can only just distinguish between the big 'uns and the small 'uns, and usually the only way I can pick out a 737 from the crowd of little 'uns is from the squashed nacelles.

BEA Information - APR 27
http://i25.servimg.com/u/f25/11/75/17/84/chassi10.jpg


http://i25.servimg.com/u/f25/11/75/17/84/chassi11.jpg

Hi,

I can agree on some of your points
Anyways ... do you read once "stalling" in the two preliminary BEA reports ...
I read this word many times here in Pprune .. not in BEA prose ...

Captain

I think you are missing something, and in doing so, appear to be sliding into what you yourself have bemoaned. This is not adversarial to the extent of being fatal to any argument. There are POV's as well as ROV's.

BEA is a closely connected agency with the principal interests in French Aviation. If you wish to promote the view that all is objective, independent, and scholarly to the exclusion of bias, we should talk.

If however you take the view that there is a history of adversarial and parochialism re: these issues, no harm, no foul.

It is legend that aircraft carry with them certain reputations. Are "Experts" hobbled with some of these prejudices?? Of course. LKP was the beginning of the problem, and the airbus cannot fall straight down, nor can it lose bits, so "we" plan accordingly, and perhaps reject preliminarily some critical data.

It's a plane, of course it can stall, saying it can't is like saying a t-tail with a stick-pusher "cannot stall". Both cases just have a bit more protection from stall - break or disable those and stalls happen (proven in past incidents)

As for coming apart at altitude, also already proven to happen (just need enough range on a SAM)

En Ligne de vol does not mean flying. The report with that phrase in clearly also shows it was falling like a brick, with low forward speed, but it happened to impact in a flight attitude. How ? Who knows, maybe jsut luck, maybe flat spin or similar

But they did look at LKP. The first air searches (supposedly) did so, and found no wreckage, and the first pinger searches also covered that area and came up blank IIRC. This latest successful search was going back over old ground, not searching new areas.


Now, if you want to do the real conspiracy theory, what is they logical conclusion if at the fourth time of looking you find something right where you looked the first time and didn't find it ? How long would it take to create convincing fake recorder data (they've done that before, right ?) and chop up enough bus bits and drop on them the bottom ? A year or so maybe ? And for the clincher, why aren't there any public photos of recognisable bodies or personal effects ? - because they wouldn't be there in a fake wreck! :E

Sad to say, but what volatile fuel for the conspiracy theorists, casing but no memory module :hmm:

re: HF slot antenna for the C130
 

Thanks for the link, RR. That same Brit ex-pat, Ben Hornby, consulted with the inventors of this antenna. It must have been his last project.

They have also built a slot antenna for the 747-1 and -2.

The spec for the DC-10 antenna is nmt 8 milliohms, while for the 767 it was on the order of 35 milliohms. Divide that into 400 watts, and you see the difference in efficiency.

jcjeant and bearfoil,

Interim Reports are, as I understand it, an attempt to supply information on known facts; not to indulge in theories. We can do the latter because we owe no responsibility to anyone except ourselves. The BEA does not have that luxury.

In their analysis of previous instances of unreliable airspeed indications, they discuss the instances of stall warnings (and criteria for same) at some length.

On a slightly different note: I subscribe to the theory that, if anything goes less than well in any human activity, it's generally due to what we Brits call "cock-up" (a shooting term) rather than conspiracy. I refer, of course, to the investigation; not the accident.

Granted that a lot is at stake here: not only for Airbus, Air France and the BEA. We will continue to try and keep them all on their toes, directly or indirectly. As for my own meagre (and sometimes flawed) contributions: my previous years of posts frequently include fundamental criticisms of Airbus design, as CONF_iture can tell you.


PS (Edit)

bearfoil, quote:
"Of course. LKP was the beginning of the problem, and the airbus cannot fall straight down, nor can it lose bits, so "we" plan accordingly, and perhaps reject preliminarily some critical data."

That's quite an accusation. I think you should tell us what data you are referring to.

CONF iture:

A pitch up/down moment in response to power changes is always to be expected in a conventional aircraft. However, the A330 is a 'fly by wire' aircraft and as I understand it, pitch changes with power are 'ironed out' by the fly by wire system. For example, on the B777, also fly by wire, the a/c has to be positively rotated into a climb attitude on a go-round, as the natural pitch up is removed by the PFCs. If AF447 was in a degraded flight control mode, the crew may have encountered an entirely unexpected pitch change, with power change, if they inadvertently entered a CB.
It is encouraging that the FDR module, although missing the CSMU, is not buried in silt to any extent. I do not see any footprints or scrape marks around the the FDR housing, so not much for any conspiracy theorists to go on.

Recorder but no memory module - isn't this unprecedented??

And to ChristaanJ, I surely hope you have better girl-spotting skills than planes :) The A330 is a catfish - the 777 is a horizontal spacecraft!

Hi,

Regretable that we have not another photo of this frame after it is moved by the ROV ... because the part supporting the memory module is partially buried in mud ...

http://i55.tinypic.com/2pq3pcl.jpg