Operational Status Data 4 corrupted?

Sorry for the baity post title.

I'm analysing the data contained in the operational_status_data4 table and I see there are too many BDS65 messages that have the bit 59 on 1. That is, it is telling us that aircraft are emmiting ACAS RA's.

I find them way too often with the A400M from many air forces. Why is this?



 

strohmeier wrote:

I'm not aware of any issues with the data collection, that would probably have been noticed by now. But that's still an interesting observation. We certainly have seen certain transponders or certain models behave weirdly in many different aspects over the years!

 

I find it weird that *only* the A400M is the black sheep. I attach a figure of the number of messages per aircraft model for the last 30 days. 

 

 [attachment=92 wrote:

Sin título.png[/attachment]strohmeier post=1513 userid=493"]It is interesting...any way to plot this on a map, or look into operators? They could be doing experiments/exercises?

Indeed. The maps can be generated using the Traffic library. Here is the link to a file containing the csv dataframe and a table of what model is each icao24.Also here are two maps showing the trajectories of this flight. To me these airplanes simply emit the hastcasoperationalstatus=True all the time while they fly.

This is the map containing all the flights that emmited an RA during a month of 2019.
   
Here you can see that some trajectories are suspicious. Like doing hipodromes or holding patterns forever (refueling?). 
This is the map without the a400m:

strohmeier wrote:

Thanks for the added detail. Well, if they are refueling, it wouldn't be particularly surprising if they have TCAS constantly buzzing, no? That would just be doing its job.
 

Honestly I had never thought about that hehe. But still, there are too many messages, although now I would love to know if they really have this issue because of refuelling. I will have a look at it.

But another question is why this only happens on operational_status_data4 and not in rollcall_replies_data4.

strohmeier wrote:

Thanks for the added detail. Well, if they are refueling, it wouldn't be particularly surprising if they have TCAS constantly buzzing, no? That would just be doing its job.

Okay I did some research lets see.
 
I downloaded messages of 30 days between May and June 2021 from two tables, rollcall_replies_data4 and operational_status_data4. In the operational_status_data4 query I added the parameters hasoperationalstatus=True and subtypecode=0 so only RA's from airborne aircraft are downloaded.

The aircraft I downloaded data from are some A400's I identified for another query.

Here is the whole code:​​​​​​ drive.google.com/file/d/1cxL2Xz89DaP51BI...awn/view?usp=sharing (I did not manage to post a code snippet sorry).

The operational_status_data4 data was downloaded in a similar way but it did not required any preparation thanks to the hasoperationalstatus=True parameter.

The results from this are weird (?). I get over 8 million messages from operational_status_data4 and only 45 from rollcall_replies_data4. 

I have the feeling that the there are so many more messages from operational status because it is ADSB and roll call is Mode S. Is this right?

Can it be because of aircraft equipment? I don't really know, I have been reading for a bit the Annex 10 Vol. 4, DOC. 9871 and the fantastic Junzis' The 1090MHz Riddle but I haven't extracted any good reason for this disproportion in messages quantity.

The mistery continues... hehe