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AF 447 Search to resume

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AF 447 Search to resume

Old 22nd Jul 2010, 17:19
  #1781 (permalink)  
bearfoil
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The discussion is engaging, but won't help find 447. So, I'll join in and suggest that information can be sent to satellite as a stream of hundreds of parameters that would moot the discovery of any boxes. Setting the transponder, or an automatic signalling when the Bus changes flight Law could break the dam and immerse a receiver with all pertinent trails. There is very near enough in ACARS to speculate within a narrow band.

Is there will in the industry? With all respect, AF and its cousins are not working their hands to the bone, and it would be a most naive partisan to say the will is powerful to locate. That 447 was out of touch is indicative of a "don't ask, don't send" attitude; Some sleeping dogs are encouraged to remain sleeping.

I am sending this message on a private system that sends enormous bags of data to a satellite, to another satellite, thence to Georgia, (US), then to Santa Clara, then back to me, in nanoseconds. Let's stop challenging windmills and ask some pertinent questions instead.

There is a system that can ionize air (airflow) intermittently, release it, to be captured, tagged, and computed as airspeed down the fuselage and sent to the Cockpit in the same micro seconds. Pitot smeet-o.

The Dark ages have never been beaten back whilst profit can be managed as a result of Risk/Benefit analysis.

bearfoil
 
Old 22nd Jul 2010, 17:33
  #1782 (permalink)  
 
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Electromagnetic radiation travels (in a vacuum) about 30 centimetres (about 1 foot) in a nanosecond. You certainly have interesting system where you live.
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Old 22nd Jul 2010, 17:48
  #1783 (permalink)  
bearfoil
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Ten feet, and I wrote ......second (s).
 
Old 22nd Jul 2010, 18:59
  #1784 (permalink)  
 
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Oh dear... backs of envelopes have gone out of fashion, I see.

EM radiation in a vacuum: 300 000 km/sec =
300 km /msec =
300 m/µsec =
300 mm/nanosec =
30 cm = abt 1 foot.

Bearfoil, don't cheat. You did write nanosecond(s), implying tens or hundreds of nanoseconds at the most, not millions. In reality you're talking about something that takes at least milliseconds.

CJ
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Old 22nd Jul 2010, 20:28
  #1785 (permalink)  
 
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Why satellites? As mentioned by others, they are expensive and low-bandwidth. The airliners already broadcast their location and speed to other planes around via ADS-B. Now improve the system slightly - have the airplanes record all received ADS-B messages. Once a plane goes missing, investigators can collect the recordings from planes that were nearby, and review the last ADS-B messages from the missing plane. This is both relatively cheap to implement and should pinpoint the last location with much better accuracy. The airplane should also have better chances at transmitting ADS-B broadcast than a directed signal to a satellite while under heavy turbulence or being upset.
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Old 22nd Jul 2010, 20:38
  #1786 (permalink)  
 
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The Shadow wrote:-

The other solution for inflight recorders data loss tinyurl.com/269cucb
..... which included in part -

The Buenos Aries (EZE) to Auckland (AKL) route is one that comes to mind - 5,600NM, and for 5,000NM of the track, the chances of having reciprocal or same direction traffic in range is basically zip/zero, i.e. the sole westbound aircraft becomes the sole eastbound service on the return leg.
Just goes to show that this thread does get read, and parts of it do get "reused" (complete with Buenos Aires spelt wrongly), in fact just plagiarized. A quick search back in this thread will prove that - post #203.

Back to the discussion. The suggestions are all good, their chances of implementation in the next 10 years are not so good, and in this case we are not splitting hairs over the number of nanoseconds, 'cos there will be super tankers full of them before anything meaningful happens.

Lets go back to the BEA's suggestion that the ULB frequency be lowered to ~9kHz. The suggestion has already been aired at an ICAO meeting in Montreal, but the likelihood of it gaining traction will only come after the ULBs from AF447 have been located and determinations made as to why their pingers were not detected.

Changing the tried and proven is going to take time.

mm43

Last edited by mm43; 23rd Jul 2010 at 00:35. Reason: added link to post #203
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Old 22nd Jul 2010, 23:48
  #1787 (permalink)  
 
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By referencing ULB, I'm assuming you mean underwater locator beacon. I think the US Navy decided many years ago that any frequency below about 500kHz belonged to them for LORAN and I don't think they've given them up (military brass are extremely reluctant to revisit the reasons for their rules - it could be embarrassing to the officer corps). Very low frequency acoustic signals travel long distances in seawater (which is why the USN snaffled them) but changing protocols for the non-revenue generating costs of FDR's and CVR's would not contribute to shareholder value for the airlines, to which their boards are legally required to adhere. The financial advisors that manage your retirement plan would be horrified to recommend that airlines spend money on safety efforts which are non-revenue generating investments which would decrease their fees (the ones they never told you about). It's unlikely that ultra low frequency beacons will appear in my lifetime.
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Old 23rd Jul 2010, 00:33
  #1788 (permalink)  
 
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kilomikedelta wrote:-

It's unlikely that ultra low frequency beacons will appear in my lifetime.
I suspect you mean VLF (Very Low Frequency) 3 - 30kHz. However, the International and US Radio Frequency Allocation table, published by the FCC, provides only that no frequency below 9 kHz can be allocated.

Frequency Allocation Table

So even though the propagation in water of VLF electromagnetic energy is possible for limited distances, the propagation of acoustic Ultra Sound energy at similar frequencies is not covered, both in air and water. There is no real conflict, whether the US Navy thinks so or not.

mm43
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Old 23rd Jul 2010, 01:00
  #1789 (permalink)  
 
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Wow, an FCC directive from July 15, 2010. Industry Canada usually takes a couple of years to get around to the lobbyists barf to make a decision. I'll have to check what Industry Canada has sucked up to the USN as far as frequency allocations. Our current government is good at sucking up to whatever the Americans want. We really don't need 65 F-22's.
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Old 23rd Jul 2010, 01:58
  #1790 (permalink)  
 
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Frequency Chart

Canada has a similar chart at:
http://www.ic.gc.ca/eic/site/smt-gst.nsf/vwapj/spectallocation-08.pdf/$FILE/spectallocation-08.pdf
The Canadian chart is more colorful and seems to have been updated in 2008. Perhaps there is a later version.

The F-22 has been canceled. I think you mean the F-35.
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Old 23rd Jul 2010, 10:39
  #1791 (permalink)  
 
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There seems to be some confusion here......

An ELT is an Emergency Location Transmitter.
It's a small package, used both on ships and aircraft.
It floats, and transmits radio waves. The frequencies used are 121.5 MHz and/or 406 MHz.
Nothing to do with VLF or ELF.

A ULB is an Underwater Location Beacon.
Its is attached to an FDR or CVR, and remains attached when the FDR or CVR sinks.
It transmits sound waves (pings), so the remarks about radio spectrum allocation are irrelevant.
Currently the sound frequency of the pings is about 30 kHz, but it has been suggested to lower this to about 9 kHz, to improve the detection.

CJ
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Old 23rd Jul 2010, 10:56
  #1792 (permalink)  
 
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ADS-B squitter

keitaidenwa

ADS-B input into own airplane's TCAS system has in fact been developed, nothing new today. Many airplanes are already squittering out GPS based own ship position by their Mode S transponder. In stead of continuous recording by surrounding traffic, satelite based monitoring on 1090Mhz seems a logical alternate option. This would also contribute to manage airspace, yet not covered by SSR's
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Old 23rd Jul 2010, 11:33
  #1793 (permalink)  
 
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Hi,

An ELT is an Emergency Location Transmitter.
It's a small package, used both on ships and aircraft.
It floats, and transmits radio waves. The frequencies used are 121.5 MHz and/or 406 MHz.
Nothing to do with VLF or ELF.
So the question is:
What happened with the ELT(s) of the AF447 ?
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Old 23rd Jul 2010, 13:19
  #1794 (permalink)  
 
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jcjant, Christiaan --
The ELT(s) would be of the mounted type, and sink along with the ship no matter how much buoyancy capability the small ELT box has. And many of these have NO buoyancy at all.

You're perhaps confusing ELTs with PLBs and EPIRBs, some of which do float and are meant to be carried out of the aircraft and into the liferaft with the evacuating crew. Liferafts may have their own locator beacons as well. But if nobody had a chance to evacuate, no ELTs or PLBs will have made it to a point when they could have started to float and transmit. The regular ELTs would have transmitted after being triggered, as long as their antennas remain above water.

Also, they are guaranteed to transmit their signals only as long as their batteries permit, the unit remains upright with the antenna out of the water, etc.
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Old 23rd Jul 2010, 16:04
  #1795 (permalink)  
 
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Originally Posted by NazgulAir View Post
jcjant, Christiaan --
The ELT(s) would be of the mounted type, and sink along with the ship no matter how much buoyancy capability the small ELT box has. And many of these have NO buoyancy at all.
To add some further info, from the BEA report S1.12.2:

An ELT distress beacon with manual tripping was also recovered. This had not been actuated. Its switch was found in the “OFF” position.
So that is what happened to at least one of them, I am not sure how many (or which type) would have been on board, but I am pretty sure that there is no requirement to carry automatic activation ELTs. I think the primary rationale for ELTs is tracing of floating survivors (who will activate them), not automatic location of wreckage.
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Old 23rd Jul 2010, 18:40
  #1796 (permalink)  
 
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Automatic ELT

Gentlemen,

per JAR, an automatic ELT was mandatorily mounted on the aircraft.

It activates automatically on crash-like G-forces and sends a short message on 406 MHZ.

This message gets through COSPAS/SARSAT.

So...

What happened to it ?
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Old 23rd Jul 2010, 20:03
  #1797 (permalink)  
 
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ChristiaanJ wrote:-

There seems to be some confusion here......
I was talking about ULBs and after mentioning the BEA's desire to have the ULB frequency lowered to 9kHz, there was some "noise" about the US Navy laying claim to that frequency. Whether I subsequently made myself clear or not, radio frequency electromagnetic energy is not the same as ultra sound acoustic energy, irrespective of the frequency being the same.

As for AF447's ELTs, one was found unactivated, and no 121.5/406MHz transmissions were ever detected.

mm43
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Old 23rd Jul 2010, 21:09
  #1798 (permalink)  
 
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Hi,

Gentlemen,

per JAR, an automatic ELT was mandatorily mounted on the aircraft.

It activates automatically on crash-like G-forces and sends a short message on 406 MHZ.

This message gets through COSPAS/SARSAT.

So...

What happened to it ?
Yes .. I repeat .. what happened to it ? ??

What is the means (safety matter) to have a bunch of emmitting emergency devices if those have to be manually triggered ?? (minus those of liferafts .. etc..)
but I am pretty sure that there is no requirement to carry automatic activation ELTs. I think the primary rationale for ELTs is tracing of floating survivors (who will activate them), not automatic location of wreckage.
It's utter non-sens ...
Can someone give the price of such devices ? must be very costly certainly ?
So .. now.. it's to spend tons of $ for search the plane ....
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Old 23rd Jul 2010, 21:50
  #1799 (permalink)  
 
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jcjeant stridently says:

Yes .. I repeat .. what happened to it ? ??

It (the primary(?) ELT) went to the bottom of the Equtorial Atlantic with the rest of the wreckage. As it got to greater depths the bits that had airpockets were crushed. That's what happened to it.

ELT's quite often fail to activate in serious crashes (though they sometimes activate on hard landings ). Even it AF447's ELT activated on impact, the signal was - literally - drowned out as the wreckage sank.

C2j
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Old 23rd Jul 2010, 21:54
  #1800 (permalink)  
 
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Bearfoil,
How many dollars per minute can you afford? Can you obtain the necessary satellite orbital positions to make it work? What are the rules for sending the data? How much power are you willing to dedicate to the problem? How much hardware expense is justified? Can you get the frequency allocations for this service?

It sounds like a good idea. It isn't, today. It may be someday.

We've been over and over this "solution" here. So far it has come up as not feasible if it is provisioned for peak traffic times for a typical 15 degree horizon to 15 degree horizon satellite.

{^_^}
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