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Old 26th Apr 2011, 14:09   #141 (permalink)
 
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Most people will be unfamiliar with notch/slot type HF aerials, because they're generally invisible under the paint.

For some unknown reason the HF slot aerials on the Concorde prototype 002 were never painted over, so this photo at least gives an idea.



An amusing detail, which illustrates the amount of HF current in the surrounding structure...
During the first in-flight tests of the HF, Concorde "wagged its tail" whenever the HF was keyed.
After some detective work, it was found that the yaw rate gyros inside the tail picked up enough HF to disturb the yaw autostabilisation system and generate spurious rudder commands.... A few filters in the right spots solved that one.
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Old 26th Apr 2011, 14:14   #142 (permalink)
 
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Ile de Sein has arrived.

Information, 26/04/2011

"The cable vessel Ile de Sein operated by Alcatel-Lucent and Louis Dreyfus Armateurs, which arrived in Dakar at 10h UTC on Friday 22 April, left the port at 18h20 UTC the same day, with 68 people on board, including the crew of the ship. It arrived in the accident zone this morning at 05h00 UTC.

During the crossing, a series of meetings took place to review the organisation and objectives of phase 5, the technical specifications of the Remora 6000 and the safety measures on board. Those present included the crew, the nine ROV operators and technicians from Phoenix International and the investigation teams.

Under the direction of the BEA Investigator-in-Charge, two working groups were formed in order to:

- continue the analysis and interpretation of photos taken by the Remus during the previous phase, in particular of the aft elements of the wreckage so as to be able to localize the flight recorders,

- study the operational procedures aimed at recovering the airplane's flight recorders, computers and parts.

A first operational dive by the Remora 6000 began this morning."
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Old 26th Apr 2011, 14:20   #143 (permalink)
 
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The video that accompanies the latest BEA announcement contains brief views of additional photos and sonar records, as well as some good shots of the Remora 6000. My French was never good enough to know whether the interviews contain important additional information.
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Old 26th Apr 2011, 14:29   #144 (permalink)
 
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Airspeed vs. Groundspeed?

Question for the experts:

When all pitot data becomes unreliable or invalid, can Groundspeed data from GPS, Inertial, Doppler, etc. be used as an alternate input. Would it be useful?
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Old 26th Apr 2011, 14:34   #145 (permalink)
 
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HF aerials etc..

Some useful references:

http://www.key2study.com/66web/acns05.pdf

Mobile antenna systems handbook - Google Books
YFS&sa=X&oi=book_result&ct=result&resnum=7&ved=0CFIQ6AEwBg#v =onepage&q&f=false
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Old 26th Apr 2011, 15:04   #146 (permalink)
 
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Quote:
Originally Posted by kit344 View Post
Question for the experts:

When all pitot data becomes unreliable or invalid, can Groundspeed data from GPS, Inertial, Doppler, etc. be used as an alternate input. Would it be useful?
Yes: Airbus submits patent for airspeed error monitoring
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Old 26th Apr 2011, 15:13   #147 (permalink)
 
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Kit344. Airspeed VS groundspeed?

Certainly, in the B777 simulator, actual ground speed data is available on the ND when air data computer airspeed data is lost due to simulated probe icing problems. There is no reason to suppose that the same would not apply in the real world.
We were using this scenario in a recent series of OPC checks and the GPS groundspeed was an excellent guide to TAS. Note that this might not be of help at high cruise altitude, where a 480 GS/TAS might be achieved at an EAS of about 260kt. A 400kt GS might have you into buffet onset. It's a much better guide below FL100.
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Old 26th Apr 2011, 16:07   #148 (permalink)
 
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Ile de Sein location

Hello,

Ile de Sein can be approximately located with this specialized web site:
AISLIVE - IMO search
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Old 26th Apr 2011, 16:30   #149 (permalink)
 
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Ile de Sein location

Dehaene:

Quote:
Hello,

Ile de Sein can be approximately located with this specialized web site:
AISLIVE - IMO search
Hi Dehaene,

I think the Ile de Sein has been out of AIS range for over a couple of days now, so any position shown is probably the last one that was received.

You might want to try this site ILE DE SEIN - 9247039 - Vessel's Details and Current Position it give more detailed info and uses Google Maps to plot the vessels when they are in range. Note under the last position received the Info Received data and time.
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Old 26th Apr 2011, 16:49   #150 (permalink)
 
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Quote:
Originally Posted by auv-ee View Post
My French was never good enough to know whether the interviews contain important additional information.
Being a native, mine should be better.

Nothing really new. Barely worth mentionning are :

Lead inspector of the BEA: We know where to go first with the ROV to have the maximum possible chance to find the recorders, even if we haven't located them for the moment. But we know where to look for them.

A Phoenix operator & the OC of the Ile de Sein: It will take time, underwater ops at those depths need precise & precautionous procedures, even if we're trained for that.
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Old 26th Apr 2011, 16:50   #151 (permalink)
 
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BEA Video

This is the video mentioned by auv-ee. It is 20+ meg, about 3+ minutes.

Sea Search Operations, phase 5

Note the chart at about 3:06 in the video. Perhaps someone with a South Atlantic chart can further pinpoint the destination.
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Old 26th Apr 2011, 17:17   #152 (permalink)
 
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A remark about 'élingues' ('slings') caught my attention in the French video.... to be used to bring some of the larger parts to the surface.

The Remoras can only pick up small bits and pieces, not entire engines or big fuselage sections.

Unless the recorders are actually lying on the seabed ready to be picked up (unlikely, to say the least), they will either have to 'scratch around' in the tail section, and try to extract the recorders, or use 'slings' to lift the entire tail section, while hoping the recorders don't fall out halfway to the surface....
Said slings having to be put in place first remotely, at 4 km down, by little robots....

I wish them luck, lots of it, and no finger trouble......
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Old 26th Apr 2011, 18:15   #153 (permalink)
 
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The Alucia still seems to be out of range. I wonder if it has returned to the site.
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Old 26th Apr 2011, 18:26   #154 (permalink)
 
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Thanks Graybeard,

A lot of very interesting and new information.

ChristiaanJ, also touched an important topic: EMI/EMC.

will keep learning,

Regards
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Old 26th Apr 2011, 18:30   #155 (permalink)
 
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Florida?

Alucia info:


Voyage Related Info (Last Received)

Draught: 4 m
Destination: PORTEVERGLADES
ETA: 2011-04-28 20:11
Info Received: 2011-04-22 05:54 (4d, 12h 31min 39s ago)

ALUCIA - 7347823 - Vessel's Details and Current Position
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Old 26th Apr 2011, 18:47   #156 (permalink)
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ChristiaanJ

Perhaps the remote operated vehicles can equip the recorders with a proper pinger on their way up in case they fall off the larger assembly....

Turbine D

Many thanks for the rundown on the GE version of Roll's TotalCare. With each TRENT's DEP, it becomes clear why constant monitoring is applied. Inflight tuning of each individual engine on wing begs a babysitter....??

Each engine has its systems, its personality(DEP), and its quirks.....



I think some patience has been injected into this thread as a whole, as I perceive a re-look at some dogma and stubborn opinion, some of it my own. The InFlight a/c is a discrete community, with a culture (micro) that obeys long standing protocol and systems. Communications with the outside world is most often last on any list of priorities. Even 121.5 is no help, before, during and after; no one flying believes a "last known position" will help the cause at all. Other than critical chat between pilots in an emergency, procedures are "trained for", and once alerted and commanded, these procedures are time proven to be executed without questions and fear. Survival is a teamwork thing, and the team is inside the ship, not away. So what has happened aboard 447 is virtually certain to have been done by professionals, well-skilled, and focused on duties, not outcome.
 
Old 26th Apr 2011, 18:56   #157 (permalink)
 
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Some vidcaps and isolations from the latest BEA video:























Chart is unmarked
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Old 26th Apr 2011, 19:27   #158 (permalink)
 
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The major lump in the lower right corner of that first image looks like it could be the APU with most of one of the APU access doors with it...?
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Old 26th Apr 2011, 19:55   #159 (permalink)
 
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GB et al,

Quote:
Airbus adopted shunt antennas in the fin from the beginning. I don't know how well they understand the dynamics, but feeding hundreds of amps into a carbon fiber fin makes me wary.
On the 388 the HF shunt sits on the metal leading edge strukture and has [a lot of] dedicated bonding paths/plates on the upper fus to feed back into the HF crate at the [very] aft upper deck.
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Old 26th Apr 2011, 20:16   #160 (permalink)
 
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Ile de Sein location

ACLS65:

I fully agree with you that MarineTraffic gives usualy much more information but the site I found is dedicated to cable ships and seems to have data from yesterday (25/4/2011 9:57:28 UTC) with a location close to LKP.

The only problem is that they do not give a precise location.
I could only find pixel coordinates on a global world map by looking at the source code of the web page.
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