Tg 747-300 From Norway, joined Nov 1999, 1318 posts, RR: 0 Posted (6 years 7 months 3 weeks 1 day 16 hours ago) and read 2813 times:
When operating on the ground at a controlled airport is it recomended to have the transponder turned on or to standby?
According to my FAA Instrument Handbook, the transponder should be turned off while on the ground to prevent App/Dep radars to "lock on" to the signal.
But a norwegian Dash-8 captain that I recently spoke to, said it should be turned on, because its easier for the ground radar to detect a SSR signal than just an aircraft structure. Thus improving safety and separation on ground.
SlamClick From United States of America, joined Nov 2003, 10039 posts, RR: 75 Reply 2, posted (6 years 7 months 3 weeks 1 day 15 hours ago) and read 2800 times:
Typical Airbus transponder control heads have an AUTO position. This is selected after engine start. It allows the transponder to transmit only when airborne.
I think I recall hearing this same feature on some other transport category aircraft.
Happiness is not seeing another trite Ste. Maarten photo all week long.
Contact_tower From Norway, joined Sep 2001, 536 posts, RR: 1 Reply 3, posted (6 years 7 months 3 weeks 1 day 15 hours ago) and read 2800 times:
Generally: STBY!!!!!
Picture this: I'm working approach control, and there are some aircraft in the traffic curcuit doing TGL. All on mode C.
Then 4-5 other aircraft taxi out, and 6 fighters crank up on the line all with mode C on.
Can you imagine the clutter directly over the airfield on my scope now!
Corey07850 From United States of America, joined Feb 2004, 2500 posts, RR: 5 Reply 5, posted (6 years 7 months 3 weeks 1 day 14 hours ago) and read 2789 times:
Quoting Tg 747-300 (Thread starter): But a norwegian Dash-8 captain that I recently spoke to, said it should be turned on, because its easier for the ground radar to detect a SSR signal than just an aircraft structure. Thus improving safety and separation on ground.
Not many airports have ground radar, especially none of the ones you would be training out of.... Keep it on standby when on the ground/while inthe traffic pattern at controlled fields.
Zeke From Hong Kong, joined Dec 2006, 6800 posts, RR: 74 Reply 6, posted (6 years 7 months 3 weeks 1 day 14 hours ago) and read 2789 times:
Quoting Contact_tower (Reply 3): Picture this: I'm working approach control, and there are some aircraft in the traffic curcuit doing TGL. All on mode C.
Approach radars are normally a mix of primary and secondary radar and have have filters that remove ground based returns like cars, trains, trucks, and ships, of aircraft on ground. Ships also have transponders.
Surface Movement Radar is normally X band, whilst approach L band (10 times the wave length), need X band to get objects close in.
Woodreau From United States of America, joined Sep 2001, 824 posts, RR: 8 Reply 7, posted (6 years 7 months 3 weeks 1 day 14 hours ago) and read 2789 times:
Quoting Tg 747-300 (Thread starter): When operating on the ground at a controlled airport is it recomended to have the transponder turned on or to standby?
It depends, some airports have a ground surveillance radar and the ATIS tells you to turn the transponder to on with the proper squawk but not ALT when you are on the controlled movement areas of the airport. (e.g. DFW)
I forgot to turn the transponder on once after I started taxiing, and ground asked "Hey... flight 1234, not receiving your transponder."
Good judgement comes from experience. Experience comes from surviving bad judgement.
Contact_tower From Norway, joined Sep 2001, 536 posts, RR: 1 Reply 8, posted (6 years 7 months 3 weeks 1 day 13 hours ago) and read 2771 times:
Quote: Approach radars are normally a mix of primary and secondary radar and have have filters that remove ground based returns like cars, trains, trucks, and ships, of aircraft on ground. Ships also have transponders.
Really? I did not know.......
Our approach radar is indeed a PSR/SSR combo, and PSR ground returs are indeed surpressed. But, surpressing the SSR data is not much of an option, because on most systems you can only surpress SSR data below a certain mode C altitude. With AD elvevation 250-ish feet, surpression of of traffic on the airport would allso surpress all low flying traffic in the areas close to the coast. (Helos, which we need to see.)
Quote: SBY: no reply/information.
ON: only a position "dot", whith no information.
ALT: position, and aditional info like altitude etc.
Correct, but in ON, which if I recall correctly is Mode A, you allso get the SSR code displayed as well. (And all radar computed info the system might have, like Ground Speed and magnetic track)
Zeke From Hong Kong, joined Dec 2006, 6800 posts, RR: 74 Reply 9, posted (6 years 7 months 3 weeks 1 day 12 hours ago) and read 2777 times:
Quoting Contact_tower (Reply 8): With AD elvevation 250-ish feet, surpression of of traffic on the airport would allso surpress all low flying traffic in the areas close to the coast. (Helos, which we need to see.)
You have provided the reason why it’s not suppressed at your location. At other locations it is.
I know airports where we can see ships on TCAS, however approach cannot see them SSR return. And they wonder why we are getting worked up when we get vectored towards a transponder return with no altitude readout, VMC its fine you can make the ship out, in IMC ……
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From Norway, joined Nov 1999, 1318 posts, 
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