There is absolutely no doubt that being able to localize the last known position of any aircraft (in any FIR) is paramount.

1. There seems to be a growing use of ADS-B where the costs of SSR installations in remote Land FIRs is prohibitive. Parts of Canada and Australia are examples where ADS-B has been incorporated into their respective country's ATC structure.
2. Security from spoofing of IDs is a matter that needs urgent attention, and can probably be dealt with by adding a couple of encryption fields to the data currently transmitted. But even in its current form, ADS-B satellite monitoring of selected flights would be a worthwhile enhancement from an SAR stand-point - especially in remote Land/Oceanic FIRs.
3. Once again, the infrastructure doesn't exist, but would be a cheaper option than a redesign and retrofit of EPIRB/GEPIRB ejectible/floatible devices, and all commercial aircraft would benefit. Problem is that at least 3 geostationary satellites need to be fitted with an ADS-B package, and I envisage we are still looking at a 10 year delay.

Further back in this thread there has been mention made of secondary data storage devices, and at least one incorporated into the Vertical Stabilizer would certainly have been of benefit in the case of AF447. Likewise, an Automatic Fixed ELT in the V/S.

mm43

Bearfoil (re 1810), satellite radios don't work every time. As a near life long amateur radio operator radios don't work a staggering amount of the time somewhere in the world. HF relies on the vagaries of ionospheric bending. VHF goes right through the ionosphere except in strange equatorial conditions when it ducts and you get taxi radio interference with taxis in the ducts in Hawaii and Southern California. VLF works over long distances if you invest in enough wire. You can't do high data rates for burst transmissions, though. Heck, that is a problem on HF, too. Multipath ruins most fast transmission modes. 10,000 bps is blazing fast for HF and requires a not insignificant amount of time to achieve lock.

Worst of all, satellites are not there when you need them. If your first awareness of a problem is the plane falls off on a wing in a massive stall - and ACARS goes off beam to the satellite. Worst yet, you are about mid way on a route between Perth and any place in South America - you are over the South Pole. You have no satellites to speak with. Look at mm43's satellite coverage maps a few messages on.
Now duplicate this on any of the air routes over the North Pole.

Add in auroras and HF goes dead for you. And on a guess I'd not want a substantial fraction of a mile of wire hanging out in aurora conditions unless there was a REALLY good way to drain off static electricity. But that last detail I am not sure about. It's an honest hunch. VLF might get through the auroral murk.

If, while you are out of contact with ANYBODY all alone for hundreds of miles in any direction who will hear your emergency transmission on 121.5 MHz or 405MHz or even 2175kHz?

This is why I wonder, "What expense is worth itself as a partial solution to the missing flight data situation?" A patch here to solve AF447 still leaves us open somewhere else if it relies on data transmission to satellites or passing ships or nearby aircraft.

I also note that so far as I know it is "easy" by some definitions of easy to transmit a mayday on 121.5 MHz and supposedly every plane in the air is monitoring the frequency. Nothing was heard. Was a transmission attempted and swamped out by various kinds of static discharges in the area a couple hundred miles around the aircraft? If the plane happened to be in a duct there could have been nobody at any place along the duct to hear it. And nearby planes would be less likely to hear it due to attenuation - signal lost to propagate in the duct.

Radio is a nice solution. I do not believe it is a comprehensive solution to this problem as proposed so far. Modified ELTs for over water use might be a good radio solution, however. (I'd propose "ejected on impacts more than 3g, floats, is wired into navigation to receive up to the second updates, and transmits that location every 20 minutes at 50 mW on 121.5 MHz FM using APRS formats. Then I'd work out the math to see if it really would work and could be setup to both float, survive impacts, and last a month.)

But none of this finds AF447 for us. It "only" makes it harder to recreate some lost recorders situations.

Has any date been proposed for the search to continue. As time goes by, it will not be any easier. Anybody else got that doudting feeling?

No reason to doubt
 

the French nation, same as the UK or US, won't want to turn it's back on its citizens

No reason to doubt.
 

The French transport minister has been quoted saying that he will wait until receiving a BEA report in early September before making a decision.

iafrica.com | travel | flights <i>Another</i> search for AF447?

AF crew also in dark...
 

Spoke to a crew member on an AF flight from Rio to Paris this week and they don't seem to know any more than the general public.

There is apparently little info coming from AF and crew get what little they know from the media.

Had hoped for some kind of insight but this is not unexpected in the circumstances I guess...

Jim

JD-EE said:
I am sure that you know more of this than I do however I think that you are perhaps exagerating the issues.

1.
I understand that Irridium works all over the globe without dead spots and can work with small hand held battery powered phones and omni antennas. With the resources available on an airliner surely there is no problem at all to phone home with at least positional information every few seconds. I would imagine that it would work for a very large proportion of the time.

2.
I would be surprised if phased array antennas were not available for non-irridium satellite work. These can be steered I would guess pretty much instantly. The technology exists to track and shoot down artillery shells and other more sophisticated missiles, I cannot believe that tracking a geostationary satellite from an aeroplane is beyond us.


All this reminds me of the landing gear weight sensor discussion. The technology was done and dusted decades ago, but for some reason there seems to be a flux of dissent explaining why it is too difficult or impractical.

The technology is available and in place on many fleets. However, cost is still a huge problem, and the "every few seconds"option would currently not be considered commercially viable.
Phased arrays are commonly in use and can be used for both geostationary and low earth orbiting (sun synchronous) satellites.

In summary, the following non ATC position reporting and emergency beacon systems are available.

1. AOC/ACARS via VHF or Satellite.
2. Use ADS-B 1090MHz broadcast position data.
3. Monitoring of 406.025MHz ELT/EPIRB transmissions -

With reference to (1), AF447 was sending a basic AOC position report every 10 minutes to AF Operations/Maintenance by a commercial data link through a geostationary satellite. This same link provided the ACARS maintenance messages.

There are currently no geostationary satellites equipped with an ADS-B 1090MHz receive and forward package, as would be required for (2) to be of use in oceanic FIRs. Localized monitoring of ADS-B transmissions can and is made by suitably equipped ground stations subject to the aircraft being fitted with the mode. Reception range is dependent on the height of the aircraft and a suitable horizon at the receiving antenna. This is obviously not suitable for use in oceanic FIRs.

Emergency beacon transmissions (3) on 406.025MHz are monitored by a number of Geostationary (GEOSAR) and Low Earth Orbiting (LEOSAR) satellites operating as the Cospas-Sarsat international satellite-based search and rescue (SAR) distress alert detection and information distribution system.

Beacons detected by GEOSAR, provided they are transmitting position coordinates, can have SAR resources deployed quickly to their position. Beacons that do not transmit position coordinates will eventually be heard by a passing LEOSAR satellite and doppler shift techniques are used to establish that beacon's position.

NOTES::

• The LEOSAR system does have "holes" in its coverage - due to a lack of Local User Terminals in some remote parts of the globe. The southern polar regions are a notable void space.
• The GEOSAR system coverage is limited to latitudes of 70 degrees and less.

Any 121.5MHz signals emitted by the ELT/EPIRBs are no longer detected by satellite, but the signal is still used by ships/aircraft and land means to home in on the beacon.

But back to position reports. The most cost effective solution for fleets operating over oceanic FIRs is to implement a more frequent position reporting regime using the existing AOC/ACARS protocols. The costs will increase proportionately, but the costs of not doing so can be equated to those incurred in the search for AF447. The cost of the former as opposed to the later are minor in the extreme.

mm43

That P2P solution - Pragmatics and Practicality
 

The post by the Shadow at #1782 suggested a mutually supportive P2P solution for flight recorder data transmission, gathering - and collation as required. I ran that proposal past my #2 son who's a very accomplished software programmer and he said "sure thing"! / "easy peasy". He maintains that it's quite a straightforward proposition, even if accomplished via HF USB. Data collection volumes only become a problem if an incident occurs and all aircraft comprising the "ships that passed that night" need to upload (data-dump) to a centralized facility. That might be accomplished by swapping out hard disks post-flight - so that aircraft never fly subsequent flights with the same HD fitted as on the prior (incident coincident) flight. The regos of those "ships that passed that night" could be determined and denominated via a data-block on the flight-plan..... and the airline/air force's ops dept asked to upload their aircraft's data.

In addition he suggested that receivers could be placed onboard selected naval and merchant vessels to help fill in the coverage holes in very remote areas.... if it was determined that accessing data from moored and solar-powered marine buoys would be too hard. You could even position one of the new solar -powered high altitude blimps astride the prominent dead-zones.

The challenge of piecing together piecemeal collected and distributed data was solved by P2P almost 15 years ago - and by NASA well before that. The need for expensive uploading to (or bouncing data off) the Iridium satellites constellation need not be a deterrent for inflight data gathering. In fact, if you wished, one of the next Moon missions could station a solar-powered telemetry unit on the lunar surface to intercept much of the transmitted traffic.... and retransmit it on request/as required.

The alternative to repetitive fruitless and futile expensive searches such as that for AF447 answers has generated will probably prove not to be as technologically challenging as everyone is making out.... i.e. cloud computing data collection is a proven capability. But it would appear to be the case now (and I tend to agree) that NOT finding a bottom line for AF447 will be quite unacceptable to all concerned..... yet that is presently the probable outcome. That's the message that seems now to be coming from many different directions. Beyond the "flight safety unknowns" context, it's quite unfair to all concerned, victims and their families included.

Has anybody found a valid conceptual flaw in the concept?

Flaws in : That P2P solution - Pragmatics and Practicality
 

WWW asks: A very basic bandwidth problem:
From post 1728 1: VHF/FM channels are sized to carry one voice channel with some accepted loss of quality. Not sure how 3 or 4 CVR channels plus the DFDR data will fit in that same bandwidth. Note that the CVR often takes extensive processing to extract the transcript, further degrading the audio quality by compressing to fit in the proposed BW would make it unusable in at least some cases.

2: "BROADCASTS", what happens when there are multiple planes within range of each other, coordinating the channels used for this broadcast without interfering with normal use would be challenging at best.

On the MOON???

Er, WeeWinkyWillie's #2 son needs to look into a transmission mode known as "Moon Bounce" to get an idea of the path loss between the Earth and the Moon. He also needs to look into "The Dark Side Of The Moon". Too often people think of that as the face away from the Earth. T'aint so, McGee. The dark side of the Moon is the side facing away from the Sun. So any transponder on the Moon would have to be passive, have a 14+ day battery pack, or else be carefully sited on a mountain peak very near one of the Moon's poles. And this has to be done in an era when we cannot repeat what a certain now 80 year old gentleman did on July 20th 1969. So servicing such a unit (batteries die) or installing such a unit at one of the poles would be a major undertaking.

My understanding is that the Iridium satellites are pretty heavily loaded at present, usually by government agencies, usually with undisclosed names. That is, however, one of the very few global coverages that exists.

Buoys need to be sited every 100 miles or so all over the globe. That would include portions of the globe in 24 hour darkness during major portions of the year. I did indeed play with Google Earth a little to discover that the routes, Perth to South America, all feature at least some time over the Antarctic ice sheet. Coverage down there would require something fancy to get through the winter, or else satellite coverage that would have to be dedicated to this purpose 24x7 lest it be preoccupied with other traffic when a plane has problems. <shrug> It can be done. How much would a dedicated data dump channel on Iridium cost per year? Maybe it's worth the cost.

Another thing that concerns me comes from my college days in the Detroit area. I was a ham radio operator. And I worked aurora bounce around the country when we had some good (lamentably at the time rare) auroras. This was on 50Mhz. I was told at the time it also affected the 144 MHz ham band. Flying through the area under the aurora is probably a radio numbing experience for most any frequency.I wonder if anybody has performed this experiment. What frequency would be needed to penetrate the murk? Fortunately, the contrived bit of my scenario is presuming a plane would have trouble in that area. At a guess the weather at aircraft altitudes is pretty benign over the poles. Any corrections to my guess?

The "problem", as I see it is to cover areas where there is a risk of being unable to retrieve the recorders, an extremely scant probability. Coverage could be extremely limited to those regions that are historically difficult for data transmission. 447 was effectively out of range, an "acceptable" parameter that needn't occur at all, in my opinion. All flights over land, and most of the Oceans, present high probabilities of retrieval of the recorders.

That ACARS was successful (and disseminated), is a case in point. Simply because the data encapsulated in the company channel speaks to a possibility of capturing accident information, that would seem to be a starting point.

Four minutes of the final entry into this a/c "diary" was directed to maintenance issues. Fine. Even this information very nearly solves the riddle without the flight recorders. Linking this channel's ennable via transponder mayday code could disable the maintenance flow, and substitute flight controls data, loads, EPR's, etc. This would be seemingly at pilot's discretion, but flipping the character of the data from saving some Mx money to transmitting the a/c's information in an emergency (certainly to include GPS fixes) seems a valid deal to me.

We are talking about a miniscule vulnerability to Radio isolation compared to system wide needs, certainly this could be done at reasonable expense?

bear

Hi,

Less than 20.000.000 so far .....
It's not yet expensive in regard of the cost of the researched object (+ - 250.000.000) and the possible reward for the victims relatives and safety if the black boxes or parts of the airplane are found ....

Er...it's the side facing away from the sun. I'm pretty sure that's what you really meant...

AF447: A lawyer wants to sue the French State

A German lawyer representing German and Chinese families of victims of the Air France disaster Rio-Paris flight, which resulted in 228 deaths last year, on Wednesday blamed responsibility for the accident on the French state.

Ulrich von Jeinsen told AFP he intends to file a complaint "against unidentified persons of the French state" which he has said were guilty of not establishing a register of incidents involving speed probes (Pitot), as requested by a European Commission directive dating from 2003.

"Because of this lack of European standards, it is possible that the French government was not aware of 30 incidents involving the freezing of similar instruments for measuring speed at high altitude," according to the firm of Mr. Jeinsen Neu-Anspach, near Frankfurt.

The Office of Investigations and Analysis (BEA), responsible for the technical investigation, believes that the failure of the pitot probes measuring speed is a possible factor in the catastrophe of June 1, 2009 in the [South sic.] Equatorial North Atlantic.

Dr. von Jeinsen wants the judge handling the matter to broaden the scope of his investigation to determine the responsibilities of representatives of the French state.

Le Figaro - AF447: un avocat veut poursuivre l'État

---------------

None of this is going to go anywhere, or go away until the wreckage is found.

mm43

Cyrano
Color me :ugh:for letting fingers type what the wanted instead of what my brain wanted.

The radio-relay of data over remote areas
 

The radio-relay of data over remote areas could be provided by a Zephyr unmanned and autonomous drone. They can stay on-station for many months at a time at altitudes in excess of 75,000 feet.
It's operational now.
.
see link
.

Air to air range 35,000ft to 75,000ft ??

Anyone??

70,000 is during the day with the sun shining. It loses about 20,000ft overnight.

I wouldn't fancy its chances in the sort of weather 447 went through, and good luck finding any bits of it afterwards.

Subsequent to the AF447 accident, and as a result of it, the BEA formed the Flight Data Recovery Working Group to undertake a technical evaluation of how improvements could be made to all aspects of recovering flight data including in-flight transmissions, storage, position reporting, along with a float-free ELT/EPIRB and ULB frequency & operating period changes.

http://www.bea.aero/en/enquetes/flig...nal.report.pdf

The most cost effective and deployable improvements are listed below:-The priority attached to solutions that stemmed from this evaluation were:-Unmanned and autonomous drones didn't even get a mention. Seems to me that they are the expensive toys of the military and spy agencies.

ADS-B was the next item on the list, but due to the infrastructure needing to be created, i.e. satellite based receive and forward hardware, this too is currently in the long-term basket.

mm43

TheShadow asks:
"Air to air range 35,000ft to 75,000ft ??"

All other things being optimal it's about 600 miles at 50,000 each end. It would go up another 100 to 150 miles or so if one end was at 75,000'. The distance to a tangent to the earth line of sight is roughly D = sqrt(2*h), where D is in miles and h is in feet. The limiting distance is found by Dt = sqrt(2*h1) + sqrt(2*h2).

As you approach that limiting distance you get some strange effects often called "picket fencing" as the signal and its bounce off the Earth constructively and destructively compete with each other.

That's academic since the range goes to about 300 miles at night at the South Pole in the Northern Summer and the Zephyr becomes Zephyr a glider and then a static object on the surface. You MIGHT get away with near continuous coverage if the Zephyr could be programmed to stay 500 miles North of the pole and follow the tiny patch of Sun it might find. I'm not sure that would be enough Sun to keep it up there with the very oblique angle of the Sun's light on its solar cells.