VARIANCE BETWEEN LIVE RADAR AND BASE STATION REPORTER

[rollerball64]

Can someone explain the following anomaly on my SBS system

I was expecting to see UAE39 flight appear on my radar screen at 12.25p.m. today but as the plane passed my observation point, nothing appeared.

However, I viewed the Basestationreporter File and found that TWO entries appeared for this plane (896121); one showing that is associated with callsign UAE39 and the other with @@@@@@@@@

SIMULTANEOUSLY, the flights to MCR and NCL  for Emirates  were absent from the Radar Screen

ANY BRIGHT IDEAS?

[DaveReid]

Can someone explain the following anomaly on my SBS system

I was expecting to see UAE39 flight appear on my radar screen at 12.25p.m. today but as the plane passed my observation point, nothing appeared.

However, I viewed the Basestationreporter File and found that TWO entries appeared for this plane (896121); one showing that is associated with callsign UAE39 and the other with @@@@@@@@@

SIMULTANEOUSLY, the flights to MCR and NCL  for Emirates  were absent from the Radar Screen

ANY BRIGHT IDEAS?

A6-ECZ (today's UAE39) is known to plot only sporadically.  

I'm investigating this at the moment, expect some more findings when I've picked it up on the way back as UAE40 in the next half-an-hour or so.

[Anmer]

Looking at my Reporter, it looks like the ModeS box(es) on 896121 may have a fault.  DaveReid is far more competent to explain this than I, but the two alternating records suggest something is amiss.  None of my Reporter records for this aircraft today show a positional plot.

The box seems to have been playing up since my first contact on 14/02/2010, though I do have three good records (with positional data between 20/02/2010 and 21/02/2010).

I can't comment on the MCR and NCL flights.

 

[rollerball64]

Thanks both

I will also look at UAE40 on the return journey which will be about 40 minutes late
 
Departed 14.35 but no show on RADAR

[DaveReid]

OK, here's what I've found.

Of 626 transmissions from A6-ECZ on the UAE40, 217 were normal Surveillance Altitude/Squawk responses, 101 were All-Call Reply/TCAS squitters, and 308 were ADS-B squitters.

However the ADS-B squitters consisted of 12 Aircraft ID squitters, 150 Airborne Velocity ones and 146 "No Position" squitters.  The latter, which aren't commonly seen, mean that the 1090ES Extended Squitter system is operational but that only altitude, not position, is able to be sent.  I assume this implies a problem with the FMS-to-transponder interface rather than the aircraft not actually knowing where it is.

One assumes that Emirates are aware of the issue - having said that, as ADS-B isn't mandatory anywhere the aircraft is likely to fly, I don't suppose that fixing it is a high priority, so we'd better get used to the idea of A6-ECZ plotting only intermittently, if at all.

Edit:  I've just looked at the AV squitters, and they have no data too (groundspeed/track), presumably for the same reason.

[Anmer]

As I said, DaveReid is far more competent than I 

[rollerball64]

I am most appreciative of a detailed description

How would we manage without the help of members such as DaveReid and Anmer

Thanks again

MikeS

[chrisg0wtz]

Out of interest 3 people called with failure to plot thisAC today!