Gulfstream 5 on RB

[EINN-07]

Hi All

Having run the ' box for the past two months now I have noticed that a significant number of Gulfstream 5 / 500 / 550 aircraft are ADS-B equipped ( unlike other biz jets )  - with a difference.

A significant number  have shown up where the position switches on and off every 3 seconds. The flight trail shows on screen but the aircraft flag is flicking on and off. Other aircraft have the flag flicking on and off with the addition of the Flight Level showing the actual and I presume spurious flight levels between FL 200 and FL 600 each time the position appears on screen.
Tonight I watched one aircraft which appeared as a 'solid' signal when it first appeared 130 nm off the Irish coast until he made land fall when it went to 3 seconds on - 3 seconds off.
There have been way too many of these ( and the fact they are all G5 ( or G4 ) ) to suggest this is a fault with RB. My guess is that this is a method of protecting aircraft position.
The question is how is this done on the transponder and is there an automatic method of detecting when the aircraft makes land fall or is it crew initiated ?

regards
Gerry

[Roadrunner]

Hi there,

I have both RB (9 months) and SBS1 (15 months) and see a large number of Biz jets in my area inbound to Luton and Stansted. I large number of G4/5 have ADS-B but I have never noticed the position alternating. I see a solid line every time albeit the only problem I have had with a few of them is being offset and landing parallel to rather than on the runway.

Could it be "Network" traffic that you are seeing like that or is it all traffic?

[AirNav Support]

EINN-07,

Could you provide us of a recording if you see this happening? as its not something we have noticed.

[EINN-07]

Support , Will do.


Roadrunner,  the position doesn't alter. The track is a continuous track. It looks like there is a method on the transponder of cycling it on and off continuously and / or getting it to send a spurious altitude read out.
As regards seeing aircraft landing parallel to the runway I've seen this on a BmiBaby 737 and guess that the transponder is out of calibration for this to happen.
The phenomenon happens with the traffic the RB receives and not with network traffic.

Regards
Gerry

[Roadrunner]

Next time I see one tracking I will set record and have a look at what is happening

[EINN-07]

EINN-07,

Could you provide us of a recording if you see this happening? as its not something we have noticed.

Support, at long last I have a few G5's captured with the symptoms above. Will I post to this thread or PM ?

Thanks
Gerry