Radar service terminates

[NorthSouth]

If you're being vectored to the ILS at an airport in Class G, under a RAS, at what point does the radar service terminate? When the pilot calls 'localiser established', or when the approach controller transfers him to tower?

NS

[5milesbaby]

Should be when you are told "radar service terminates"

[Chilli Monster]

When transferred to tower.

You just don't get told it in those circumstances because stating the obvious (tower cannot, by definition, be a radar service) would be a complete waste of R/T time.

[52 North]

Interesting question, what about the following scenario...

You are in radar at an airfield outside CAS, you have been providing a RAS to an inbound, you have transferred your inbound to tower and you suddenly notice a fast moving unknown going towards the inbound, what do you do?

For me, the RAS continues for the inbound until the aircraft is on the ground, if necessary I provide a RAS through the comms of the tower controller.

[Pie Man]

As a thought!

How about once the aircraft passes through the levels shown on the radar vector chart (RVC) - as we are told we cannot provide RAS below those levels.

Or is the thing about not providing RAS below the RVC just a military thing?

Regards

Pie

[NorthSouth]

52N:you have been providing a RAS to an inbound, you have transferred your inbound to tower and you suddenly notice a fast moving unknown going towards the inbound, what do you do? For me, the RAS continues for the inbound until the aircraft is on the ground, if necessary I provide a RAS through the comms of the tower controller.But if said inbound is already sailing down the ILS and probably below the min altitude specified in the final approach area of the RVA, the only action the pilot can take to a traffic warning is a go-around. So it's not really a RAS any more is it? And a RAS-at-one-remove-via-the tower-controller sounds like something ATSSD would be interested to hear more about.
NS

[52 North]

Pie Man

Yep, I agree with you about what the Part One says about cancelling a RAS below RVA levels, however what would you do in the scenario I quoted?

I know what I wouldn't do and that is ignore the contact just because the inbound was below the RVA level. Perhaps an expedited climb to the RVA level then an avoiding action turn?

In which case is the Part One wrong? Instead of stating:

"ATSUs providing a RAS shall set a level or levels at or above which the aircraft will remain within the limits of radar cover and be provided with the requisite terrain clearance. Below this level or levels a RAS shall be refused or terminated."

should it not state:

"ATSUs providing a RAS shall set a level or levels at or above which the aircraft will remain within the limits of radar cover and be provided with the requisite terrain clearance. Below this level or levels radar vectoring under a RAS shall be discontinued"


52N

NS

I agree that doing anything once removed is not ideal, however surely doing nothing in that scenario is even worse. As I stated to Pie Man, a climb to the RVA level then an avoiding action turn may be an answer, all depending on the time available I guess.

52N

[52 North]

As an addition to this thread, when providing a RAS and you clear the aircraft for a visual approach, do you downgrade to a RIS as you are no longer in control of the level?

[Chilli Monster]

You are in radar at an airfield outside CAS, you have been providing a RAS to an inbound, you have transferred your inbound to tower and you suddenly notice a fast moving unknown going towards the inbound, what do you do?

Pass the traffic information to the tower Controller and leave the decision of what they do between them and the crew of the aircraft - it's not your decision anymore. Flight conditions may be such that the Captain of the aircraft decides to continue with the approach.

As an addition to this thread, when providing a RAS and you clear the aircraft for a visual approach, do you downgrade to a RIS as you are no longer in control of the level?

Normally by the time I clear the aircraft for the visual it'll be from a position that transfer to tower is acceptable, still at a level at or above minimum RAS provision level - so the question never arises.

[benedictus]

I can't remember the exact wording in the ANO but even under a RAS the Pilot is still responsible for terrain clearance. I know that the MATS 1 differs from this and I would and do downgrade to a RIS when releasing traffic for a visual approach from a RAS.

As for terminating the radar service, I heard a tale of a Scottish ATCO providing a RAS to traffic inbound to one of the Islands, didn't terminate the service, said traffic crashed into the sea after transfer and he was criticised for not terminating the service as it was possible the pilot considered he was still receiving a radar service.

[52 North]

Pass the traffic information to the tower Controller and leave the decision of what they do between them and the crew of the aircraft - it's not your decision anymore.

How does that sit with the Part 1:
"Approach control may instruct approaching IFR flights to contact aerodrome control before transfer of control has become effective. Until approaching aircraft are flying with visual reference to the surface, aerodrome control shall not issue any
instructions or advice which would reduce the separation established by approach control."

[VCR]

at or above minimum RAS provision level

And how many units have one of those specified?

[Chilli Monster]

How does that sit with the Part 1:
"Approach control may instruct approaching IFR flights to contact aerodrome control before transfer of control has become effective. Until approaching aircraft are flying with visual reference to the surface, aerodrome control shall not issue any
instructions or advice which would reduce the separation established by approach control."

It says "may".

In all honesty I don't think the situation has ever arisen with myself, nor do I intend to operate using that particular caveat - I don't think it's appropriate for Class 'G' operations. The traffic only gets the visual approach when it's visual with the airfield or surface - not before. Therefore transfer is done at the time of contact.

[Pie Man]

N52

In your senario I would pass traffic information and leave the pilot to decide a course of action - he could ask for an avoiding action turn. The climb above the RVC may not be an option due to other traffic. The traffic information should be passed as controllers we have a 'duty of care' to ensure pilot/aircraft safety. Should it all go very badly wrong the question you could be facing is did you do all that could be expected of the average controller in the conditions - difficult one to call.

Regards

P

[Pierre Argh]

Quite possibly one of the oldest... and biggest bones of contention. Answers coming in about termination of radar service from all over the place... UK military ATC regs are confusing.

The radar controller is, basically, responsible for the aircraft making an instrument approach until on the runway... or until transfered to Tower when making a visual approach (paraphrased). But... a controller cannot give RAS below the Radar Vector Chart levels, and is limited in when (s)he can do so under RIS. (This came about when regs were tightened up following a couple of CFIT incidents?)... But, frankly, the regs are illogical!

Forget ILS, have a look at the PAR procedure to see how ridiculous it is... Aircraft under RAS at FAF at height of RVC, starts descent on the glidepath and is now below RVC... Controller is, theoretically, unable to continue to provide vectors i.e cannot do the a PAR? In the limitation there is, IMHO, no recognition that approach and departure procedure are designed within approved criteria, to ensure that terrain clearance is maintained? Ask any pilot what they would expect from a controller providing a talkdown if they were IMC on approach and he saw a dead-ringer confliction, and I bet the answer isn't traffic information?

My honest answer... I'd give avoiding action coupled with, in all probability, an instruction to break of the approach (seems like common-sense to me?). I believe this is currently excerising the grey matter of the men in grey at High Wycombe... but don't hold your breath?

[NorthSouth]

52N:Perhaps an expedited climb to the RVA level then an avoiding action turn?But your problem would be that if it's unknown traffic with no verified Mode C, or no Mode C at all, you have no way of knowing that you wouldn't be climbing your traffic into conflict with it. And as you rightly say, you couldn't give your traffic an avoidance turn if it's below the min vectoring altitude.

Surely the only available course of action is to give traffic info to the pilot and leave him/her to decide what to do with it? The lower they are on the approach the more chance they're in VMC and therefore able to manoeuvre visually if necessary - or at least to satisfy themselves that the unknown is not a conflict.

Reminds me of the incident at a unit which was bedding in a new radar which had lots of spurious contacts. Approach had just put an inbound 737 on a closing heading for the ILS when he told him "c/s pop up traffic in your 12 o'clock half a mile left to right no height information". Not sure whether he was in IMC at the time but it must have focused two pairs of eyes! This was in Class D by the way so not as scary as your scenario.

Pierre Argh: Not sure the regs re RAS/PAR are as illogical as you suggest. The big difference between the two is that PAR provides precise and independent vertical as well as horizontal information, and it's that vertical info that enables the PAR controller to maintain the aircraft's safe separation from terrain.

NS

[Pierre Argh]

North South... my point is that when marshalling an aircraft for a PAR, Mil regulations require that an IFR service continues to the runway, and once past the FAF, on PAR the controller is having to pass vectors... in otherwords (s)he is vectoring the aircraft below RVC levels, which we are told we cannot do?

I fully agree that PAR... and for that matter ANY instrument approach procedure provides terrain clearance, (and would add that terrain clearance under RAS is clearly defined as a pilot's responsibility)... I cannot see why regulations do not say something like, "Vectors will not be provided below RVC unless established on an approved approach or departure procedure ... surely that would cover the situation?

[Married a Canadian]

Why not just ask the pilot if he is happy to maintain his own terrain clearance? In VMC that should simplify matters.

[Pierre Argh]

Agree with MaC... but what's simple got to do with it?

[AlanM]

MaC - you valid yet?!?!?!?! :)

[Canary Boy]

And as if all of that wasn't confusing and contradictory enough - DUTY OF CARE raises its ugly head! :\