ATC Question

[Captain Galactic]

An aircraft is being vectored for an ILS approach. The pilot asks if they can fly directly to a 7 mile final for the approach which is the 'commence descent' point on the FMS and the controller allows it. Who is now responsible for safety altitude at this stage? For example if the controller now clears the aircraft to descend below MSA is it legal for the pilot to accept?Cheers guys.

[ItchyFeet2]

Aircraft no longer on radar vectors, pilot responsible for terrain clearance, not ATCO.

[Scooby Don't]

Itchy - agreed. A/C is now on own navigation, and is responsible for terrain separation from the moment own nav is accepted.

[GunkyTom]

Have to disagree. If an a/c is on 'own nav' ,certainly in CAS it doesn't change YOUR responsibility to allocate terrain safe levels. If he continues for a vis app then he is accepting the responsibility. We, on a daily basis allow a/c to self position if they want but still control the level until they continue with the ILS/VOR etc or position for a vis app

[bigmanatc]

If radar service was terminated...then...the pilot is responsible for terrain clearance...if not terminated and aircraft allowed to fly own heading then atc responsible...but I have`nt yet heard a controller allow an aircraft to fly own headings while under radar control...kinda defeats the objective:bored:

[Spitoon]

ICAO PANS-ATM says:
8.6.5.2 When vectoring an IFR flight and when giving an IFR flight a direct routing which takes the aircraft off an ATS route, the radar controller shall issue clearances such that the prescribed obstacle clearance will exist at all times until the aircraft reaches the point where the pilot will resume own navigation.

I guess that it all depends on whether a clearance for a pilot to fly direct to the centrefix (or whatever one chooses to call it) represents 'giving an IFR flight a direct routing which takes the aircraft off an ATS route'. In my view it does and whenever I allow an aircraft to self-position I continue to assign terrain safe levels. Never had a problem and done it loads of times (when it is quiet).

I seem to recall that the ICAO doc was amended a few years ago to remove the ambiguity in the text. I'm not sure that they achieved this objective!
...but I have`nt yet heard a controller allow an aircraft to fly own headings while under radar control...Get out more....

[Scooby Don't]

I know of a situation in which a controller gave own nav to FACF and descent to 2,000 feet, which was terrain safe at the FACF but NOT where the a/c was when given the clearance (MVA of 6,000 feet!). The a/c descended like a ton of bricks, to well below MVA.
When investigated, the controller was found to be free of blame. Would I do the same? No. Does it show that the onus is on the pilot? Yes. This was under strict ICAO, not UK, rules.
In a procedural environment, a/c will often be given "descend with the procedure" or similar when well outside the safe area for that descent. It's not as if we know (or are supposed to know at any rate) exactly where the aircraft is, so the pilot must take responsibility for terrain clearance. A can of worms can be opened up with aircraft under radar control requesting procedural approaches. Who is responsible then???
This may be an area of national differences, but I'm fairly sure (don't have a copy to hand) ICAO Doc 4444 puts the responsibility for terrain separation on the pilot when under own navigation.

[GunkyTom]

TO BIGMANATC
...but I have`nt yet heard a controller allow an aircraft to fly own headings while under radar control...kinda defeats the objective:bored:

Re headings-The objective isn't to keep a/c on YOUR heading at all times, it is to keep standard sep and if that involves allocating headings, then so be it, however, if there is no traffic to affect then I allow vis apps, own nav etc. It is no different to an a/c self positioning to a hold . I don't know what airspace you work in and wouldn't be so presumptious to say what you should do, maybe you have to keep control at all times however, I work in class D surrounded by A. My previous unit was the same and prior to that D,A and G so based on that and in answer to the question, responsibility remains with the ATCO until the a/c is established or continuing visually. If the a/c wants to follow an unpublished procedure for that airfield, then either don't allow it or keep vertical control until you or he are happy.

[Scooby Don't]

"until the aircraft reaches the point where the pilot will resume own navigation."

Therein lies the issue - own nav makes it the pilot's responsibility, but where does own nav begin? It could be taken as being the moment when the a/c has finished turning from the previous course to the new course direct FACF or wherever. It could be taken as being when the a/c has reached the point to which it was sent direct (which could be a DTW or IAP) or you could ask "confirm on own nav DCT PLACE".

I now declare this can of worms open. :E:E:E

[airac]

There was a supplementry instruction No 6 of 1999 (originally published 1991) that covered this topic quite well. The supp stated ,amongst other things:-
There may be ambiguity over the responsibility for terrain clearance due to possible differences in the interpretation of " Radar Monitoring" by pilots and controllers.

MATS pt 1 Section 3 chpt 1 page 9 now states

9.8 Self-positioning of aircraft

9.8.1 Controllers should exercise caution when approving self-positioning to final approach and are not to initiate reference to the 'Centrefix' or other locally used term.

9.8.2 If controllers are in any doubt about the location of the 'Centrefix' or other position referred to by a pilot, they are to ask the pilot to define this position and take this definition into consideration when carrying out their controlling duties.

I would tend to agree with gunky, after all you can give a RAS to an A/C which is on its own navigation.

When this situation crops up , I give a ,not below xxxx' until established.
works for me.:)

[GunkyTom]

airac 'When this situation crops up , I give a ,not below xxxx' until established. works for me'

I use that phrase all the time too

[GunkyTom]

Scooby I am sure there are differences between area and terminal and also country to country but your example is a little confusing.If the a/c was cleared to descend to 2000', then I would have thought the controller was liable. If it wasn't a clearance, what was it ? If an a/c is doing a proc app, regardless of whether it is in a procedural or radar environment, then the responsibility for terrain sep will be covered by the procedure which will specify where/when the a/c can descend.A safe level will be allocated until the a/c reaches a point at which it follows the procedure. The advantage with radar is you can see if it doesn't follow the procedure which in my experience happens quite regularly but if you can't see it, you won't worry!!!

[Spitoon]

There was a supplementry instruction No 6 of 1999 (originally published 1991) that covered this topic quite well. The supp stated ,amongst other things:-
The SI also stated that 'Aircraft are to be allocated levels in accordance with MATS Pt 1 and Pt 2 [procedures]'. Sadly this rather useful bit of advice - which appeared to remove any ambiguity in the UK at least - has been lost now that the SI has been incorporated into the main body of the document. Perhaps there is no need for it because MATS Pt 1 Section 1 Chapter 5 says:
14 Terrain Clearance
14.1 Controllers are to ensure that levels assigned to:
a) IFR flights in receipt of a radar control service
b) flights in receipt of a radar advisory service and
c) flights in receipt of a radar information service and receiving vectors;
provide adequate terrain clearance for the phase of flight as shown below.

It then goes on to give the minimum clerances for particular situations.

There is no distinction between aircraft under vectors and those on their own nav. If the aircraft is IFR and getting a RCS then the controller must ensure that levels assigned provide terrain clearance (the trouble is that it doesn't explicitly rule out a situation in which no level is assigned, ho-hum).

Whilst it did seem strange to have SIs from years ago not incorporated into the main document, at least when the full SI was there you could see the context for the instruction and everything that was originally intended. Still, I'm sure the MATS Pt 1 Editor knows what he is doing.......

[airac]

Spitoon I agree except

The MATS Pt 1 Editor knows what he is doing.......

[Spitoon]

Ah, so you know him then....

[loubylou]

If the aircraft has been cleared on a visual approach then the controller is no longer responsible for terrain clearance , but is responsible for making sure the aircraft remains inside controlled airspace.
If the aircraft is not cleared for a visual then the controller has responsibility for terrain.
So - I reckon that the first post - then the aircraft had not been cleared visually therefore the controller could not give descent below MSA and possibly in the case that scooby don't described - maybe the aircraft had been cleared on a visual?

louby

[radar head]

If the aircraft is navigating on an IFR clearance then ATC is responsible for terain clearance and should stipulate a terain safe cleared level/altitude. If the pilot declares that they are "visual" and wishes to fly to a specific point, then the pilot assumes responsibility for terain clearance.

[Spitoon]

radar head, whilst I recognise that your local books may say something different, I refer you to the ICAO 'baseline' of 'When vectoring an IFR flight and when giving an IFR flight a direct routing which takes the aircraft off an ATS route, the radar controller shall issue clearances such that the prescribed obstacle clearance will exist at all times until the aircraft reaches the point where the pilot will resume own navigation.' which is slightly different to the principle that you describe.

[OA32]

If an a/c requests to self position for the ILS i would clear them to, not below the MSA and ask them to report established at which point clear them for descent on the ILS. Of course with this new ILS phraseology could you say "when established on the localiser descend on the ILS" I always consider myself responsible for their terrain clearance unless they are on a visual approach and I just have to keep them from descending outside controlled airspace.

[This is a crisis]

To my mind, centrefix approach does not make any reference to any sort of instrument approach procedure and is certainly a very dodgy area when it comes to terrain clearance.

My method, if asked for a centrefix approach, has always been to clear the aircraft down to the platform level as if it were to carry out a procedural approach, advise him that descent below this level is at his/her dicretion and ask them to report established on final. I dont mention any sort of approach or give any conditional descent clearance.

Thoughts?

[chevvron]

And Centrefix is defined as..? There was a Supplement to MATS Part 1 telling controllers to beware of this.

[judge11]

'If the aircraft is navigating on an IFR clearance then ATC is responsible for terain clearance'.

Responsiblity for terrain clearance ultimately rests with the aircraft commander, no ifs or buts, whether under radar control or not.

[BurglarsDog]

Trying to keep it simple;

In my experience and from reading sevral versions of National procedures around the bazaars, and without an exact reference :

Regardless of any clearance issued by ATC, the pilot is responsible for the safe conduct / operation of the flight

And, ATC for their part must, for their part, only issue safe clearances especially in regards to terrain.

To cope with some of the potential grey areas highlighted here, I would adopt the "Dont assume check" principle.

I suppose its a joint responsibility really - bit like marriage:}

DogGone;)