Radar services

[brtch]

My question is about radar services:

What are the two radars services encountered in the UK, and what are the differences?
Thanks.

[Llamapoo]

Maybe its worth asking this one over in the ATC forum.

And are you referring to military vs civil etc? Or Radar Control Service vs Radar Advisory vs Radar Information?

They'll be able to tell you better than me though.

[Timothy]

Well, no-one else has picked this up, so I'll have a go.

I can't think what "two" services you are thinking of, unless you mean primary and secondary, but they aren't services.

The three main services that a Civilian pilot will be offered are:

Radar Control: You are positively identified and must do what you are instructed (subject to caveats about the final responsibility resting with the aircraft commander). This is only available inside controlled airspace, and is the norm in most CA in most parts of the world.

Radar Advisory: Only available outside controlled airspace and generally only available to IFR traffic. Warnings are given of potential conflicts and avoiding action is suggested to the pilot. This action may legally be ignored by the pilot, but the controller will immediately downgrade the service to Radar Information.

Radar Information: Only available outside controlled airspace, to IFR and VFR traffic. The controller will warn the pilot of conflicting traffic, giving its range and bearing and, if known, its altitude, but does not offer avoiding action. It is entirely the responsibility of the pilot to take action to avoid a collision or air-prox.

Any of these services may be provided by Civilian or Military units.

If you were thinking of Primary and Secondary, this has been explained at great length on this forum before, but to cut a long story short, primary depends upon a radar pulse being reflected by the aircraft, whereas secondary requires a piece of equipment (transponder) to pick up the radar pulse, encode some data on it and retransmit it. The data retransmited might be as simple as a 4 digit code (mode A), but usually also includes the aircraft's altitude (Mode C) and, increasingly, other flight data (Mode S).

Hope this answers whatever your question was ;)

W

[whowhenwhy]

3 different kinds of radar service in the UK. Radar Control (RCS) provided inside CAS in which pilots are given mandatory instructions. The other 2 types are outside CAS. Radar Advisory Service (RAS) which can only be requested if flying IFR. Under RAS you will be provided with info about conflicting traffic and advised of avoiding action to achieve standard separation (in class G 5nms and 3000'). You don't have to take the turns (it's advisory) but you then are solely responsible for separation. It's worth knowing that if your RAS is limited due to high traffic density, even though you may not be told, standard separation may not be achieved. Under Radar Information (RIS) you will be provided with info about the conflciting traffic and nothing else. You are solely respsonsible for separation. Traffic info will not be updated unless you request it or we think you need a gentle reminder because you don't seem to have done anything about it. Hope that's vaguely understandable. I've left out a fair few of the other conditions of each but the ones I covered are the major-ish ones.:ok:

To add to what was said above, mil controllers shouldn't straight away downgrade you to a RIS because you've only said that you're happy to continue against one particular conflicting ac, not everything along the length of your route.

[Shagster]

hi WWW,
I was just curious, why wouldn't you inform the pilot that he was receiving a limited service if he was operating in an area of high traffic density?

[nats]

S'ter,
To quote from MATS part 1,Sect1,Ch5,P4,para1.6.2 re radar services,
'Controllers must inform pilots when they limit the service and ensure that pilots are made fully aware of the implications of any limitation'.
There are various examples mentioned in the good book,including limiting the service in areas of high traffic density.

[whowhenwhy]

Shagster,

On reading my post I suppose I wasn't very clear, you would tell the pilot that he was receiving a limited service, it's just that some controllers tag on the end that standard separation may not be achieved. Others believe that this is implicit in the statement that you're limiting for high traffic density!

[jack-oh]

In reply to the question "what type of service do you require", I was recently asked by a North Flight ac from Bergen to INV "what ones have you got". This didn't inspire confidence in the pilots understanding of the legally binding contract between the two of us.

[ILS 119.5]

About 2 years ago I was vectoring a Canadian registered minibus for an ILS approach under the callsign "Kestrel" with a Canadian crew. When I asked if they could accept a Radar Advisory Service outside controlled airspace the pilot asked "what is a radar advisory service". This also reiterates that in some foreign countries RAS and RIS are not provided and thus foreign pilots do not understand the implications of such services. Even though some airports need to provide radar services outside CAS, if you can keep them within CAS then do so.

[whowhenwhy]

Ahhh, but the USAF always have the best answers to this question. Ranging from the response "Can I have the full service please Sir?" to "Well sir I require 150 gallons of fuel and a screenwash at Mildenhall please Sir!" (Can't remember the actual numbers, but hey, you get the picture!:ok: