AF 447 Search to resume (part2)

[mm43]

RR_NDB;

A new way to measure an aircraft’s air speed using ultraviolet lasers has been developed by the BAE. By using the unique properties of light, this technique works at any altitude and even at low speeds where conventional methods struggle.

The article is 5 plus years old, and you'd think that if the proposal was deemed viable that someone would have "blown their trumpet" in recent times.

[Machinbird]

The article is 5 plus years old, and you'd think that if the proposal was deemed viable that someone would have "blown their trumpet" in recent times.

Perhaps people are waiting for the patent to run out. Perhaps there wasn't strong enough financial incentive to switch. What did it take to make AF et al to be motivated to change out pitot tubes which on a per aircraft basis is "chump change."

The technology to implement this concept has to be getting easier and easier to implement. Wouldn't be surprised if the Chinese are using the technology on their latest fighters.

[takata]

Originally Posted by tubby linton

"In auto mode, the amount of heat provided by the heaters is modulated following what the "probes" themselves are sensing. When anti-ice is selected ON, full heating is provided, whatever the "probes" are sensing. It makes sense if you are considering that the "probes" are freezing because the heaters were not delivering the correct amount of heat at the first place."
That is not how I read 1.30.50 p1/2.There are two heating modes with Airbus,low heat on the ground and high heat when airborne for the pitots.There have been numerous incidents where this changeover has not occurred giving the crew lots of problems.I have also seen where the pitots have cooked in the sun of the Indian Ocean to a threshold above the warning causing nuisance ecam.

Reconsidering your comment in the light of the manual, the hard fact is that, (I'm sorry), but you may be absolutely right about this point!
I'm trying to find where I have read that without success! Now, Turbine D's original question can't be answered as the crew could have refered also to another anti-ice push buton (engine, wings) unrelated with the probes/windshield heaters. The most probable explanation would then be that icing ended (all by itself) at probe's level if no "super-heating" was ever available.

[Machinbird]

BTW, look who filed the Pat:

Airbus operations (SAS)

Yes, but this late 2009 patent is for a system of implementing laser velocity measurement systems on an aircraft, not for the UV laser anemometer.
And of course, it is written in typical Patent Lawyerspeak and is virtually gibberish on a quick read through.

[mm43]

Killing two birds with one stone - IAS and AOA

So Airbus are being proactive in this matter. There's bound to be a test aircraft already fitted and work underway to get national/international certification. The whole tone of the patent application is one that fits neatly into AI's current FBW concepts. No more blocked pitots or frozen AoA vanes.

Will it be safe from laser attack?

[Machaca]

Depicted heading is from LKP to debris field (018.8 T) and placed to bisect the engines:

[Machinbird]

Will it be safe from l@ser attack?

The big issue will probably be eye safety of the maintenance folks.

Assuming the laser can operate at a relatively low power level and still produce results, and that the focal distance is also relatively short, then it should be a fairly safe item.

You could still mount it on the VS to keep it further from people. You could also power it down on the ground unless the aircraft knows it is in a takeoff mode. Ground test modes would then be where the hazard is.

[mm43]

bearfoil;

I suggest it is not indicated that the tail hit first ...

I think you are following my thread of thought, i.e. the vertical component of the impact was so high, that whichever part of the aircraft touched the water first had little bearing on the outcome, as various parts of the structure disintegrated almost instantaneously as the horizontal and vertical moments were cancelled out by an impeding wall of water and buoyancy moments respectively.

I envisage that the "hand-clap" effect to the wings was extreme and coupled with horizontal impediment they sheared off at the now crushed wing box root.

[jcjeant]

Hi,

Repost the mapping of the wreck makes me think of a question.
The captain and copilot seats are clearly identified.
Does anyone read or heard comments from BEA on these seats?
They were occupied by human remains?
What was the condition of seat belts ... etc. .. ?

[takata]

Sextant avionique is part of the Thales group (Thomson-CSF) from 1989 and the manufacturer of Thales probes. In fact, Thales is a relatively new entity (2000) regrouping similar sectors from ex-Thomson-CSF, Alcatel, Aerospatiale, Dassault, DCN,... It is also a partner with Raytheon (USA) in a joint venture and Thales (UK) is also regrouping many UK Defence firms. Then, it is not more a "French" group than EADS is, but Dassault is, (still I think), one of its main private shareholder.

[Machinbird]

Does anyone read or heard comments from BEA on these seats?

They recovered two seats with remains, and the chart has 4 seats (including the 2 crew seats) marked in red indicating (we suspect) that they have been recovered. "Who was flying?" would have to be one of the key questions that the accident investigation would have to settle. This recovery was done very early in the recovery effort, so it is likely that the judiciary and BEA both agreed that these particular remains needed to be recovered. Until there is a positive identification, I doubt that there will be an announcement of who/what was the target of that particular recovery.

[RR_NDB]

Replies

Hi,

Jcjeant,

3 cabin crew, (not cockpit) seat belts were not being used. i´m sorry.

takata,

I will do a patents search on this issue. Can show the "trend".

Machaca,

Why not a SSE trajectory. Together "combined sea currents" may be coherent.

But IMO the chances of these models to be confirmed by readable FDR data are low. Too many variables > risky.

Machinbird,

Assuming the l@ser can operate at a relatively low power level

I will analyze all similar patents.

[Machinbird]

RR_NDB

IIRC cockpit seat belts were not being used.

If true, that would be very significant. Any idea where you think you saw that?

[RR_NDB]

I corrected the error in previous post

Machinbird,

I replied fast and shortly after (double checking) detected my error.

The reason was yesterday night reading BEA #2 pg 71 concerning cabin crew seats

I´m sorry.

[takata]

Originally Posted by Machinbird

If true, that would be very significant. Any idea where you think you saw that

Nowhere.
There was zero communication about what was actually recovered in the deep concerning either who, and how. It looks like a confusion with those FA seats floatting in June 2009 which were unoccupied. Here again, there was a lot of speculations about that while 3 out of 9 FA should have been resting in the FA module (which is not for the pilots).
Remember also the time of the flight -at night: LKP was at 23h10, departure time, 02h10 Zulu and 04h10 at arrival time. Most passengers should have been sleeping after more than 3 hours of flight, as they would have landed in the morning in Paris.

S~
Olivier

[Machinbird]

Originally Posted by Machinbird
If this can happen in an A320, why cannot the same thing occur in the A330?

Takata

I had a quick look at this report for refreshing my memory but this quote was a shortcut in the report. It looks like ADR3 was already rejected due to AoA wrong data (in fact good) by ADR1 & ADR2 vote (both being false due to blocked AoA probes). Then, at this point, they had only two ADRs left in opposite sides of the fuselage; hence when they started to vary due to abnormal attitude, none could be retained and the flight envelope protection was kicked off.
Consequently, this ADRs rejection was primary the result of the two probes already blocked, not this unusual attitude direct consequence (as you'll have two probes in the same side which should not be affected by disymetrical flight).

Hi Takata,
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 apologize for being slow to respond-I now run a business full time .
I'll be posting more later on dynamic loss of control possibilities. What you call a "rogue C-3PO."

RR_NDB, I understand the source of that wild remembrance of yours. It can be heck to get old. Too much data-and how do you keep it all filed properly.

[RR_NDB]

Laser sensor

Machinbird,

You could still mount it on the VS to keep it further from people

I think is not a place because air would be affected by fuselage at high AOA.

[Machinbird]

Takata

Nonetheless, I'm sticking with the impact description provided by the BEA and I can't see why such a description would imply a mandatory "deep stalled" attitude ; the vertical vector may also be due to inertia. There is no description of an excessive pitch rate at sea level (alpha Max should be well above 35° if she had some thrust remaining). Without much more details provided, it may look also like a CFIT attitude to me.

Hi Takata,
I have looked at that concept of the accident and rejected it for energy considerations. From the available evidence, AF447 hit with considerably more vertical velocity than horizontal velocity. But the total velocity seems to be a bit lower than I would expect from a CFIT event on a no flap aircraft. Now that is strictly a judgement call on my part, and I could be proved wrong when they present the data recovered from the FDRs.
I do have as a basis for judgement, however, a comparable military accident where I participated in the accident investigation. But it still comes down to a judgement call. The total energy of the aircraft appears to have been too low for a CFIT event in my estimation. All that is then left is a deep stall.

[jcjeant]

Hi,

The captain and copilot seats are clearly identified.
Does anyone read or heard comments from BEA on these seats?

Sorry if I spread confusion .. but my wonder was about the captain an copilot seats only .. no the flight attendants seats ...
I suppose BEA know all (visual) about the state of those seats .. belts etc .. as we have seen sharp pictures of many other objects
So .. it's to wait a communication of the BEA about ............
Belts used or not used can be a important indication.

[takata]

Turbine D & tubby linton,
Back on the question "Why pressing the pb ON for Probe/Window HEAT, when those heaters are already working in automatic mode?"

At least, I have found this part on the procedure in the FCOM 3.02.34.
Now, I'm sure that pressing the pb ON (in flight) will do something, and that my first explanation (from memory) could also be the right one: super-heating.