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Old 27th Mar 2014, 07:11   #8321 (permalink)
 
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AU-501

The T7 is fully FBW, with three different modes, from full blown "normal" mode with the likes of envelope protection through the more basic "secondary" down to "direct" where you get rid of the computers and are signalling the actuators directly but still electronically from the flight deck controls. There is also a very limited manual "backup" capability to some of it's control surfaces.
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Old 27th Mar 2014, 07:13   #8322 (permalink)
 
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Is there any website that would be able to give water and weather conditions between the partial handshake (8:19) to no Handshake (9:15) am in the area under investigation on the date of the incident?

This would show the probability of a largely intact set down with a smaller initial scattering of debris field (if water were calmer) or a much larger surface break up accounting for multiple spotting of large pieces of debris as is now showing up on various Satellites.

Any attempt to keep the aircraft as intact as possible to hide it as seems the case would have taken this into account......

Any experts out there to advise if 2005 Tsunami Debris could still be around in that part of the world?
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Old 27th Mar 2014, 07:35   #8323 (permalink)
 
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Quote:
HMAS Success is a supply and support vessel of Australian navy.
1400NM SW of Perth
Despite news reports to the contrary they are continuing to search despite the poor weather.
Sometimes 30-40 crew on lookout
8-12 crew on lookout as a minimum 24/7
Has a crane that can lift debris.
Connectivity with crew and their families is limited due to being "far out"
Their task is continue to search until asked to stop by authorities.
Highly trained and professional crew who are up to the task.
Previous task was to the North of oz mainland in support of operations.

The skipper has an impressive cv with an interest in aviation.
https://www.navy.gov.au/biography/ca...allison-norris
And they do have a copter on board:

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Old 27th Mar 2014, 07:42   #8324 (permalink)
 
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Wikipedia:

Quote:
Most FDRs record approximately 1725 hours worth of data in a continuous loop.

They are designed to emit an underwater locator beacon for up to 30 days and can operate immersed to a depth of up to 6,000 meters (20,000 ft).
Quote:
An underwater locator beacon (ULB) or underwater acoustic beacon is a device fitted to aviation flight recorders such as the cockpit voice recorder (CVR) and flight data recorder (FDR).

A 37.5 kHz (160.5 dB re 1 μPa) pinger can be detectable 12 kilometres (0.621.24 mi) from the surface in normal conditions and 45 kilometres (2.53.1 mi) in good conditions. A 37.5 kHz (180 dB re 1 μPa) transponder pinger can be detected 45 kilometres (2.53.1 mi) in normal conditions and 67 kilometres (3.74.3 mi) in good conditions. Transponder 10 kHz (180 dB re 1 μPa) range is 79 kilometres (4.35.6 mi) in normal conditions and 1722 kilometres (1114 mi) in good conditions.
Some posts on this thread contradict the above.

So which part(s), if any, of the above quotes are incorrect to the extent that on-or-above sea surface searches with appropriate equipment won't locate the FDR when within the ranges stated?
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Old 27th Mar 2014, 07:45   #8325 (permalink)
 
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Earl

Basically the hydraulic actuators for the primary flight control surfaces are signalled electronically from the flight deck controls, with the degree of computer input/ moderating that takes place dependant on the level at which the FBW is operating at ( normal >secondary>direct). However just in case of a total electrical failure Boeing did indeed provide a manual back up in the form of good old fashioned cables to the stab and selected spoilers...according to the FCOM:

"Mechanical Backup
In the unlikely event of a complete electrical system shut–down, cables from the flight deck to the stabilizer and selected spoilers allow the pilot to fly straight and level until the electrical system is restarted."

Last edited by wiggy; 27th Mar 2014 at 10:23.
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Old 27th Mar 2014, 08:22   #8326 (permalink)
 
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Debris

Hi , I have read every post on here and I am wondering if there could be a lot of debris still floating about from the hurricane that hit the Philipines not long ago?
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Old 27th Mar 2014, 08:39   #8327 (permalink)
 
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Quote:
Originally Posted by auraflyer View Post
Apart, of course, from empirical testing they did against actual aircraft on actual flights ... which confirmed the results of the "algorithm" [sic] ... which was actually an analysis of hard data received by the satellite operator from the plane and some very clever work by some exceptionally good and quite under-appreciated engineers.

And the fact it wasn't detected on radar to the east

Or to the north

Or to the west
Oh I think everyone appreciates their work. What is frustrating is that the details of their analysis has not been made public. I don't blame Inmarsat for this, it is down to the Malaysia transport authorities to produce a report with all the details which are known, but not released.

I fully understand the anger and frustrations of the family members. At this stage in the AF447 investigation the BEA issued an interim report with everything known, including full details of the ACARS messages, crew bios, cargo manifest, the works.

It is not enough to have the big man say "The plane is lost, some clever people in England have worked it out, trust us." Show us the work. Show us the ping details, show us the cargo manifest, show us the radar track, give us the ATC transcript, even!

Last edited by glenbrook; 27th Mar 2014 at 08:41. Reason: typos
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Old 27th Mar 2014, 08:40   #8328 (permalink)
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Quote:
Originally Posted by Erwin Schroedinger View Post
Some posts on this thread contradict the above.

So which part(s), if any, of the above quotes are incorrect to the extent that on-or-above sea surface searches with appropriate equipment won't locate the FDR when within the ranges stated?
Not sure exactly to what contradiction you refer. Is it range propagation? You mention 'above sea surface'.

Are you inferring that a 'microphone' or hydrophone not in the water can detect the ULB? Looking at the cross media transmission first, the speed of sound in a dense medium (water) is around 4800 feet per second and around 1100 feet per second in air. A wave or sound beam will refract at the media boundary. At certain angles it will be reflected rather than pass through. The physics example is a light beam striking a prism and 'total internal refraction.' IIRC, a beam of light passing from a dense medium to a less dense medium will be refracted away from the normal.

However the sea is not an homogenous mass of water. Temperature and salinity vary with depth. The water body has well defined layers; it is possible to even see and feel these layers when scuba diving. The speed of sound will vary with salinity (hence density) and temperature. Sound waves on striking these layers will either reflect or pass through depending upon the vertical angle between the emitter and the hydrophone.

It follows that a hydrophone directly above the emitter might hear the ULB but in most of the figures you have quoted the signal strength may decline too much for surface capture.

The first thing then is to determine the bathythermal layers and place the hydrophone in the same layer as the emitter. Next is to lower the hydrophone so that it would be as close as possible in the vertical to the emitter to maximise its horizontal range.

You would then have a sweep width of between 4 km and 44 km depending upon water conditions and the figures you quoted being applicable.
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Old 27th Mar 2014, 08:42   #8329 (permalink)
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Quote:
Originally Posted by cawky View Post
Hi , I have read every post on here and I am wondering if there could be a lot of debris still floating about from the hurricane that hit the Philipines not long ago?
The Indonesian archipelago is a 3000 mile barrier from the Malaysian coast to the north of Australia. Such debris would have had to travel counter current through narrow straits, passed Australia, to the Indian Ocean.
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Old 27th Mar 2014, 08:43   #8330 (permalink)
 
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Quote:
A 37.5 kHz (160.5 dB re 1 μPa) pinger can be detectable 1–2 kilometres (0.62–1.24 mi) from the surface in normal conditions and 4–5 kilometres (2.5–3.1 mi) in good conditions. A 37.5 kHz (180 dB re 1 μPa) transponder pinger can be detected 4–5 kilometres (2.5–3.1 mi) in normal conditions and 6–7 kilometres (3.7–4.3 mi) in good conditions. Transponder 10 kHz (180 dB re 1 μPa) range is 7–9 kilometres (4.3–5.6 mi) in normal conditions and 17–22 kilometres (11–14 mi) in good conditions.

Some posts on this thread contradict the above.
The following link to an early AF447 thread post by auv-ee explains the basic facts of pinger location by someone who knows and has been actively involved in this work.

AF 447 Search to resume

It wont take you long to work out that there is a relatively narrow range either side of the towed path which is dependent on th TPL being positioned around 1600 meters above the seabed profile.

Last edited by mm43; 27th Mar 2014 at 08:59.
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Old 27th Mar 2014, 08:49   #8331 (permalink)
 
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Quote:
Originally Posted by Neogen View Post
And they do have a copter on board:
Do you know that it actually departed with that on board, there has been many delays getting those operational..
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Old 27th Mar 2014, 08:53   #8332 (permalink)
 
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@Pontius Navigator
I postulated in earlier post that because the Maldives have 2 767's and a 757 that maybe they're not too careful with garbage disposal and that this was an old part chucked away.
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Old 27th Mar 2014, 08:57   #8333 (permalink)
 
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A Thai satellite has picked up 300 items of what appears to be debris about 200 km from the French debris patch. Just so frustrating the weather is bad for the next 24 hours.
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Old 27th Mar 2014, 09:10   #8334 (permalink)
 
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In discussion about that supposed mine or fire bottle in the Maldives, does anyone seriously believe that the authorities would not have looked into the alleged finding by now? If they have and it was significant then does anyone seriously believe that so many governments would still be wasting so much money and resources searching 5000 miles away?
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Old 27th Mar 2014, 09:18   #8335 (permalink)
 
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Quote:
Do you know that it actually departed with that on board, there has been many delays getting those operational..
Yes, it departed Fremantle with that MRH90 on board.
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Old 27th Mar 2014, 09:19   #8336 (permalink)
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Quote:
Originally Posted by ZAZ View Post
Are they looking for a 37 kHz radio signal or audio signal? Big difference. And yes u can still buy crt Cro,s. And LCD oscilloscopes, so are they listening for sound waves in which case u use a transducer or radio waves which travel under water?? To subs at 65 kHz,
As mentioned earlier, a 37kHz radio signal is in the LF range and needs a very large antennae and considerable power to radiate any significant range.

37kHz audio, is in the VHF audio range capable of being detected with a transducer and then displayed on the appropriate equipment.
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Old 27th Mar 2014, 09:45   #8337 (permalink)
 
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Some larger pix here:

Thai satellite spots possible wreckage | Bangkok Post: breakingnews
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Old 27th Mar 2014, 09:53   #8338 (permalink)
 
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its been close to a week now that the australian authorities had said that a few possible aircraft debris been seen on satellite images. since then so many aircrafts and ships been doing rounds of the suspected area and still its so surprising that not even a single piece of debris is visually identified and checked hands on just so to make 100% sure that the aircraft has crashed there.
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Old 27th Mar 2014, 09:56   #8339 (permalink)
 
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Satellites seem to spot whatever you want them to spot. If you want them to find evidence of chemical and nuclear facilities they'll oblige. If you want them to spot dinner plate sizes of aircraft wreckage they'll oblige. Anyone who has a satellite wants to be able to say they have spotted something. At this stage its all one-upmanship. All this manpower searching, nothing found, too many false positives.
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Old 27th Mar 2014, 09:56   #8340 (permalink)
 
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Quote:
BANGKOK (AP) - A Thai satellite has detected about 300 objects floating in the Indian Ocean near the search area for the missing Malaysia Airlines jetliner.

Anond Snidvongs, director of Thailand's space technology development agency, said Thursday the images showed "300 objects of various sizes" in the southern Indian Ocean about 2,700 kilometers (1,675 miles) southwest of Perth.

He says the images were taken by the Thaichote satellite on Monday, took two days to process and were relayed to Malaysian authorities on Wednesday.


Images here. It would be useful to get some background from analysts on the rarity of seeing this type of flotsam on satellite images.

https://twitter.com/RodrigoEBR/statu...495424/photo/1
Without trying to be too negative these images and the French images of yesterday look like ice. I took the picture below over seas to the South of Greenland a couple of years ago; height around 30000ft.

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