Af Flight 447; Amateur Radio Operators, Help Needed

[CFIT]

Seeking help from global amateur radio operators who may have intercepted radio transmissions from Flight 447 :

AF447 - Page 25 - PPRuNe Forums

Post # 497

It may be a good idea to spread the world to the L-band people and ask if someone was recording Satcom ACARS on June 1st on 1700 band,

ACARS txm:s is via VHF ground network or switched to L-band via Satcom. Therefore it is normal that amatuers don´t pick up any of the txm:s on L-band. If the downed 330 had an array-mounted antenna for L-band txm:s and was doing a violent out of control flight, mother in Paris (receiving dish) should have a threshold point on rx, and as the flight may have been doing a lot of txm:s, it would be possible that more txm:s was aired but not recived by "mother" due to the gain-step setting (eB/no) in the receiver in Paris if the array-antenna was out of it´s prime focus during the last minutes.

As there are a minor group of dx:ers active on the L-band (microwave band), it could have been possible that additional data could have been receieved and stored on a hard drive at a l-band fan amatuer, as amatuers always are on the edge of possible receiving limits-settings. The only issue is if ACARS is encrypted and how hard encrypted any ACARS-txm:s would be to decode.

Is there a back-up recordings at Satcom NOC downlink-station, or is Paris the only active downlinker for AF ACARS txm:s. It could maybe be a good idea to spread the world to the L-band people and ask if someone was recording Satcom ACARS on june 1st on 1700 band, especially if worst scenario occurs wheres the "blackbox" never gets retrieved or are in a degraded condition.

Just a thought in this tragic situation.

Sincerely

Thomas in Stockholm / engineer.

Edit-1: Not sure if this link is the right antenna-config, but phase-arrays can be tilted a lot and mantaine communication, suspect more that the CB:s would damp the signal to a critical threshold depending on downlink size of dish and eb/no-setting.

Link is: http://www.emssatcom.com/pdf/AMT-3500.pdf

Edit-2: Also in mind, these array-antennas has a specific radiation pattern, and when accessing satellites, usually the NOC keeps an record on time-signal strength etc for tech-monitoring and billing purposes. So with the NOC data and the previous post of the ACARS messages, it could may be possible to determind the angle of the A/C if a calculation was made of NOC telemetric-data compared with the time-stamp of ACARS txm:s, as we know the pattern and how is mounted on the A/C body.

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End of Post

[CFIT]

This would be about 02:00- 02:20 UTC , Monday June 1

http://www.jacdec.de/info/AF447Special/jac...eport_AF447.htm

Timeline

19:03 - Departure at Rio de Janeiro-GIG - ~22:05 AF 447 is passing Natal and is heading out over the Atlantic at 35.000 feet and with 450 knots - 22:33 last radio contact, AF 447 passing INTOL waypoint - 22:48 AF 447 left controlled airspace of CINDACTA 3, north of Fernando de Noronha Island - ~23:00 AF 447 entered a zone of thunderstorm clounds and turbulences - 23:10 ACARS message indicates that the autopilot was disengaged, fly-by-wire systen reverts to alternate law, data from both pitot static ports lost, TCAS antenna at fault - 23:11 both air data units flight computers (ADIRU) failed, standby attitude indicator (ISIS) lost - 23:12 diagreement of ADIRU data - 23:13 two flight management computers (PRIM1 + SEC1) failed - 23:14 AF 447 sent an automated message indicating an electrical problem and a possible loss of cabin pressure - 23:20 - estimated passing of waypoint TASIL - 02:33 alarm war raised and the search rescue mission began -

Edited June 8, 2009 by CFIT

[bkkjames]

CFIT, for those of us who have lives (JK ), can you bullet point this in laymen's terms please?

[sanook2me]

Its a good question alot of amatuer radio hams around the World but in Thailand?

I can't get a good wifi or mobile connection half the time so not sure about transmissions from t'other side of the World.

[Maizefarmer]

.... odd thread for TV

My understanding (a HAM myself) is that they are not encrypted - but they are digitaly modulated (D8PSK if I am not mistaken - with something around 15Khz to 25Khz b/width).

As far as Thailand is concerned, L-banders are very thin on the ground - personally don't know any active L-banders.

But that all aside, isn't tec. reporting preceeded with a request - which, without the "go ahead - send" acknowledgment from the Rx side, don't get sent (the purpose of the request been to set up an audit trail).

BBC World service was saying (at 3am this morning) that the 23 or 24 messages that were received were all demodulated and recorded. As for missing messages (?), thinking about it, [even] in ideal circumstances I wouldnt have thought an L-band Tx of any sort at the output levels that the tec messaging service runs on would be to propogate its way round to Thailand, and I wouldn't the downlink from the satelite (footprint) doesn't cover Thailand does it(?)

CFIT - are you a Thai based HAM?

[JetsetBkk]

...CFIT - are you a Thai based HAM?

- takes balls to ask that.

[Carib]

This would be about 02:00- 02:20 UTC , Monday June 1

http://www.jacdec.de/info/AF447Special/jac...eport_AF447.htm

Timeline

19:03 - Departure at Rio de Janeiro-GIG - ~22:05 AF 447 is passing Natal and is heading out over the Atlantic at 35.000 feet and with 450 knots - 22:33 last radio contact, AF 447 passing INTOL waypoint - 22:48 AF 447 left controlled airspace of CINDACTA 3, north of Fernando de Noronha Island - ~23:00 AF 447 entered a zone of thunderstorm clounds and turbulences - 23:10 ACARS message indicates that the autopilot was disengaged, fly-by-wire systen reverts to alternate law, data from both pitot static ports lost, TCAS antenna at fault - 23:11 both air data units flight computers (ADIRU) failed, standby attitude indicator (ISIS) lost - 23:12 diagreement of ADIRU data - 23:13 two flight management computers (PRIM1 + SEC1) failed - 23:14 AF 447 sent an automated message indicating an electrical problem and a possible loss of cabin pressure - 23:20 - estimated passing of waypoint TASIL - 02:33 alarm war raised and the search rescue mission began -

Posted the list with ACARS messages on the other thread about this accident.

http://www.thaivisa.com/forum/Air-France-P...08#entry2788208

Edit: The aircraft " spotter " community is also deep into ACARS, since that is a part of their hobby.

Edited June 8, 2009 by Carib