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Old 27th Mar 2014, 04:37   #8321 (permalink)
 
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"ZAZ - "Oscilloscope" was precisely the word, the U.S. Navy officer used in the interview."

Nothing wrong with using an oscilloscope to look for a voltage (amplitude) at a particular frequency. If they were looking at a range of frequencies, they'd use a spectrum analyzer. They'd need to look at the 37.5khz, since it's beyond human hearing range, unless they down convert it to human hearing range.

Last edited by Coagie; 27th Mar 2014 at 05:01. Reason: Adding a space.
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Old 27th Mar 2014, 04:53   #8322 (permalink)
 
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All SAR activity cancelled for the rest of the day due to the weather.
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Old 27th Mar 2014, 05:02   #8323 (permalink)
 
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Here is a photo you won't see very often (not everyone is in the picture)
but Aust, NZ, US, Chinese, South Korean and Japanese military personnel all
in the same room and working together.

The guy speaking is Australia's defense minister, the Chinese are in Blueish Camo
and the guy in the suit.


Last edited by 500N; 27th Mar 2014 at 05:13.
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Old 27th Mar 2014, 05:06   #8324 (permalink)
 
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All in the same room

500N - thank you for posting that. A nice image and a touch of sanity among the madness and posturing. That is what international aviation ir actually about.
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Old 27th Mar 2014, 06:01   #8325 (permalink)
 
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A method to find the actual crash location?

During the search for AF447, France's BEA commissioned a working group (The Drift Group) to evaluate all the methods of backtracking wreckage floating on the surface.

This did not produce sufficient accuracy for a viable search and actually seems to have delayed the location of the wreckage.

The Drift Group report can be found here:
http://www.bea.aero/en/enquetes/flig...oup.report.pdf

There was one useful jewel in the report, but it didn't fit the group think concept and so was ignored. Appendix 7 of the report contained an anomalous "pollution spot" detected by the Cosmo-skymed synthetic aperture radar satellite. The shape of the spot was unusual and it was very close to the LKP.



MH370 was likely flown to fuel exhaustion however there would still be some fuel retained in the tanks which would have spread out on the surface and changed its radar reflectivity slightly. Jet fuel would evaporate fairly quickly with the rate likely dependent on temperature and surface turbulence and wind velocity. In the case of AF447, the slick was predicted to evaporate within 30 hours. MH370 would undoubtedly be a shorter period.

There is some chance of a detectable slick. The Cosmo Skymed is a small constellation of satellites designed to revisit areas relatively quickly, and there may be a fair chance of detection of a fuel slick from the crash of MH370.

Here is a link to the Cosmo Skymed information and tasking site:
https://directory.eoportal.org/web/e...s/cosmo-skymed


To improve the odds of detection it would really be useful to narrow down the area of interest by finding actual floating wreckage and backtracking it using whatever means possible.

The collected data from the Cosmo skymed satellites appears to be stored in bulk and is extracted as needed based on tasking requests.
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Old 27th Mar 2014, 06:36   #8326 (permalink)
 
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Interview with commander of HMAS Success

ABC news live radio interview with the skipper of HMAS Success, Captain Allison Norris.

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

Last edited by mickjoebill; 27th Mar 2014 at 07:12.
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Old 27th Mar 2014, 06:54   #8327 (permalink)
 
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G,day Earl,

I am not B773 rated. However and if any triple types can say otherwise, I do believe that the A/C has conventional PWRs assisted controls not FBW the exception being a spoiler on each wing and T/E flaps.

Not trying to be a smart arse, just like a bit of clarity.

Comments anyone without departing fm the subject of the thread
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Old 27th Mar 2014, 07:11   #8328 (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   #8329 (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   #8330 (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   #8331 (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   #8332 (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   #8333 (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   #8334 (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   #8335 (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   #8336 (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   #8337 (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   #8338 (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   #8339 (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   #8340 (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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