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Odd aircraft ICAO 123456 and Reg: SPCTRLX Flight: XA0000

Dick
 

In a 20 minute period I logged 38 messages from 123456 (Aircraft, Airborne).
Two of them showed the Reg, suggesting that a connection was established despite the odd ICAO.
But I guess we already have determined that no ICAO valiation is done (at this level).

123456 (Aircraft, Airborne) -> 10931A (Ground station): Command
AC info: -, -, -
GS info: EDDG, Munster Osnabruck
AVLC type: I sseq: 0 rseq: 0 poll: 0
ACARS:
Reassembly: skipped
Reg: SPCTRLX Flight: XA0000
Mode: 2 Label: Q0 Blk id: 0 More: 0 Ack: ! Msg num: M10A

123456 (Aircraft, Airborne) -> 10900A (Ground station): Command
AC info: -, -, -
GS info: EHAM, Amsterdam
AVLC type: I sseq: 1 rseq: 0 poll: 0
ACARS:
Reassembly: skipped
Reg: SPCTRLX Flight: XA0000
Mode: 2 Label: Q0 Blk id: 1 More: 0 Ack: ! Msg num: M11A

Cheers,
Dick

Tomasz Lemiech
 


On Fri, Jun 12, 2020 at 9:23 PM Dick <hobbyd@...> wrote:

123456 (Aircraft, Airborne) -> 10931A (Ground station): Command
AC info: -, -, -
GS info: EDDG, Munster Osnabruck
AVLC type: I sseq: 0 rseq: 0 poll: 0
 ACARS:
  Reassembly: skipped
  Reg: SPCTRLX Flight: XA0000
  Mode: 2 Label: Q0 Blk id: 0 More: 0 Ack: ! Msg num: M10A

Judging from the flight number, it's probably a business jet of some kind. They often use ARINC as their datalink provider and neglect to configure the proper flight number. As a result, a default flight number of ARINC is used (XA comes from XAA = ARINC designator).

I've seen SPCTRLX reg in an ACARS message on June 1st, but I was unable to match it to any aircraft with my ADS-B archives.

To make this even more bogus, this guy often sends ES-IS Hello packets with NET address of 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00. This does not seem to work...

Cheers,

--
Tomasz Lemiech

Dick
 
Edited

On Fri, Jun 12, 2020 at 09:53 PM, Tomasz Lemiech wrote:
As a result, a default flight number of ARINC is used (XA comes from XAA = ARINC designator).
I was aware that XA most often indicates a business jet, but didn't know where this XA came from.


To make this even more bogus, this guy often sends ES-IS Hello packets with
NET address of 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00.
So did this one on 2020-06-08.
Haven't logged the one on June 1st.

Although the signal strength of one of the VDL2 messages suggests it was quite close,
[2020-06-08 23:21:42 GMT] [136.975] [-2.6/-47.5 dBFS]
I could not find an aircraft in my ADS-B log that fits.

During the 20 minutes in my log it connected to these in this sequence:
GS info: EDDV, Hannover
GS info: EDDG, Munster Osnabruck
GS info: EHAM, Amsterdam

PS.
Can the source in the Call Request be used as a clue?
X.25 Call Request: grp: 11 chan: 255 src: 04432126 dst: none

Cheers,
Dick

Tomasz Lemiech
 


On Sat, Jun 13, 2020 at 10:34 AM Dick <hobbyd@...> wrote:

PS.
Can the source in the Call Request be used as a clue?
X.25 Call Request: grp: 11 chan: 255 src: 04432126 dst: none

Of course! It's an ICAO hex written in octal.

;-)

--
Tomasz Lemiech

Dick
 

On Sat, Jun 13, 2020 at 10:48 AM, Tomasz Lemiech wrote:


Of course! It's an ICAO hex written in octal.

;-)
Of course :-)

Dan Henry
 

On Fri, Jun 12, 2020 at 02:23 PM, Dick wrote:
In a 20 minute period I logged 38 messages from 123456 (Aircraft, Airborne).
Hi Dick,

Total trivia, but I think the VDL2 to mode-s comparison is interesting.

When I saw your original post before any replies my first thought was octal, but for a completely different reason.

On all of the military mode-s and ads-b transponders I have worked with the mode-s code is always entered in octal format.  It is usually originally "hard coded" with jumper wires or by shorting pins by maintenance in a procedure called "strapping."  Then the aircrew can display it and override the entry if needed, but always in octal format.  We also have some military aircraft flying in civilian configurations with normal transponders, also programmed in octal.

US military usually start with a hex of AExxxx.  The crew always sees this as octal 534xxxxx and that is the format displayed in the aircraft "781" maintenance forms and usually on a placard in the cockpit.  Normally mode-s / ads-b code errors that are "typos" do not look like typos unless you compare both values in octal formal.

What surprised me about your VDL2 123456 hex code, is that I had always assumed VDL2 data entry was also done in octal.  The 123456 example seems to indicate that it is actually entered or displayed in hex, the same way we see it.  Either that or the person entering the octal code for that which is not very likely! (grin)

Over the years I have used PlanePlotter data to train and correct many bad military mode-s codes in my area.  I always include a hex to octal conversion in my explanation because the octal value is the only one the aircrew ever sees.

-Dan

Sergio Sarabia
 

I have seen many ACs with that code, I think they use it provisionally:

Dick
 

On Sat, Jun 13, 2020 at 07:49 PM, Dan Henry wrote:


Total trivia, but I think the VDL2 to mode-s comparison is interesting.
And educational, as I did not know that they used to be 'coded' in octal.
Apparently these days it is just a keyboard.

That makes me wonder if the SP(ace) CTRL X is a keyboard sequence that ended up as the Reg.

Cheers,
Dick

David Stark
 

I think newbies are submitting test and rotating ICAO codes to the basestation database.

-Dave, NF2G, k2