ADS-B Aircraft Blacklist

[Kurt A]

Stemming from another conversation around spurious ADS-B spikes; for those interested, I have been manning a blacklist of aircraft who are notorious for transmitting incorrect position reports.
These are only aircraft that have been operating in, out, or around YSSY.

Here is the unfortunate list of repeat offenders I have personally recorded over the past year:

7C4366 //Nauru Air Corporation 737-33A VH-NLK
7C1473 //Qantas Airways A-330-202 VH-EBP
7C6C6F //V Australia Boeing 777-3GZER VH-VPD
C81C17 //Pacific Blue Airlines 737-8FE ZK-PBK
E8023F //LAN Chile A-340-313X CC-CQF
7C6C71 //V Australia Boeing 777-3GZER VH-VPF
C817CC //Pacific Blue Airlines 737-8FE/W ZK-PBD
E8023E //LAN Chile A-340-313X CC-CQE

You might have your own list, or may have an update to mine. If you've noticed an improvement on any of the above aircraft, please let me know and I'll remove them.
I guess the only real way of knowing if any of these aircraft above still offend is for me to clear my plot's blacklist and compare the plot over time once again.

DaveReid puts it nicely:
The only conclusion that can definitely be drawn from a spike is that something has produced an ADS-B transmission that SBS or RadarBox has been able to decode and interpret as an aircraft at a significantly longer ranger than normal.

This could be due to either atmospheric conditions causing reception range to be greater than usual (i.e. the position reports are being correctly decoded), a garbled transmission (one or more bits corrupted) which results in a spurious position report or, in a few cases, an aircraft which is incorrectly encoding its position.

The best way to determine which is the most likely explanation is to look at successive position reports from the same aircraft.

Hope this is of some use for other radar spotters around Australia.

[Nigel C]

Naughty aircraft! ;)

[Bob Peake]

Karl,

As you would expect, Airservices monitors ADS-B performance and carries out various checks before it uses ADS-B for air traffic control. With respect to the aircraft on your "Blacklist", they fall into several groups

7C6C6F //V Australia Boeing 777-3GZER VH-VPD
7C6C71 //V Australia Boeing 777-3GZER VH-VPF
C81C17 //Pacific Blue Airlines 737-8FE ZK-PBK
C817CC //Pacific Blue Airlines 737-8FE/W ZK-PBD
This group were all equipped with a version of a Mode S / ADS-B transponder that had a fault. This fault has now been fixed, so you can remove them from your blacklist.

E8023F //LAN Chile A-340-313X CC-CQF
E8023E //LAN Chile A-340-313X CC-CQE
These two aircraft are fitted with an old GPS transponder that does not meet CASA's requirements for an ADS-B data source. They should be upgraded before the flight level 290 and above ADS-b mandate comes into force in December 2012.

7C4366 //Nauru Air Corporation 737-33A VH-NLK
The standard ADS-B message from an aircraft includes information about the accuracy and integrity of the data source. This information is ignored by boxes like the SBS-1, but is critical for determining if the data is suitable for air traffic control. Transmissions from this aircraft indicate low accuracy / integrity, so it never gets through to the ATC system. The data source is probably an inertial nav system rather than GPS. Again, it needs to be upgraded before Dec 2013.

7C1473 //Qantas Airways A-330-202 VH-EBP
No problems have been observed with this aircraft. The only suggestion I can think of is that the observed anomaly might have been attributable to the position decoding method used. To unambigously determine an ADS-B position it is necessary to use "global CPR decoding", which requires processing of two separate ADS-B messages, referred to as "odd" and "even" message types. Some processing software uses "local decoding" with only one message, which sometimes produces anomalous results. Suggest you remove this one from your blacklist.

Regards

Bob.

[Bernie P]

Karl,

...

I didn't know we had a Karl!?!? :D :D :D

[Kurt A]

We can go with Karl, lol.


Hi Bob,

Thanks for updating us with the latest information regarding the "blacklist". This is great news and your update is very much appreciated.

So currently the maintained list looks like this:

7C4366 //Nauru Air Corporation 737-33A VH-NLK
E8023F //LAN Chile A-340-313X CC-CQF
E8023E //LAN Chile A-340-313X CC-CQE


Are there others we might need to be aware of presently? Also, might you have any intel on the latest one that Grahame recorded as incorrectly reporting it's position?

71BF52 //Korean Air Boeing 777-2B5 HL7752

P.S: I received your PM and am very much in favour of your suggestions. I just hadn't yet had a chance to reply properly with my thoughts. But I very much look forward to working with you to put something together that will be of value.

[Philip Argy]

I didn't know we had a Karl!?!? :D :D :D

Be nice, Bernard!

[Bernie P]

Haha, Philip, i was thus the :D :D :D at the end :o

On a similar, but slight different issue, 5/8/12 I was on the following flight

VH-TJX TN0494 05/08/2012 21:54 Qantas B737-476 Melbourne-Sydney (http://16right.com/)

Now this was a QF flight, yet it had the TN details, puzzeled much!! :eek:

[Grahame Hutchison]

Bernie, The old TJ series B737s all transmit the TN flight ID. Don't think they bothered changing it changed when Australian was merged into Qantas way back.

[Bob Peake]

Kurt,

Apologies for converting Kurt to Karl in yesterday's post - at least I got two of the four letters right.

Regarding the question about Korean Air Boeing 777-2B5 reg HL7752777, address 71BF52, at present we have all the KAL 777s marked as suspect because they have the same faulty transponder as the Virgin aircraft had. The list includes KAL aircraft with the following addresses
71BD31
71BD32
71BD33
71BD34
71BD73
71BD74
71BD75
71BD98
71BF14
71BF15
71BF33
71BF34
71BF50
71BF51
71BF52
71BF64
71BF65
71BF66
71BF82
71BF83
71BF84
71C208
71C209
71C210
71C222

Sorry to add so many new entries to your blacklist.

Regards

Bob.

[Kurt A]

Thanks Bob,

Thanks for the information. I have updated my list with the KAL entries.
The latest offender was this morning's LAN aircraft, who was seen well over the drink between Perth and South Africa:

E8023C //LAN Chile A-340-313X CC-CQA