Approach Clearance

[captainpaddy]

Hi there!

I posted this question on another forum but on mature reflection thought it would be better here!

Question: You are flying towards an ILS approach with a published initial platform altitude of 2500 feet. You are presently at 4000 feet and, say, 14 miles out when ATC give you an intercept heading and clear you for the approach. Is it expected that you will descend to 2500 feet as published or maintain 4000 feet until on the glideslope? Or, do you have a choice??

Would the answer change if you are significantly off the extended centreline when giving the intercept heading?

Many thanks for any replies!!

CP

[2 sheds]

[QUOTE=Mike Jenvey] Bear in mind that for numerous airports, the ATC clearance would be something like:"Turn left heading xxx degrees, clear intercept localizer Rwy AA, called established."Then, once you had called localizer established, you would then be cleared to descend further with the glide-path. QUOTE]

"Something like..." What kind of talk is this??! That is nothing like the standard UK phraseology - and the aircraft would be instructed to descend on the ILS - the GP is not used in isolation.

The relatively recent addition to phraseology (a couple of years ago, now) of "when established on the localiser, descend..." is available for use at any unit if tactically useful.

[captainpaddy]

OK guys, I'm not really that worried about the phraseology used in a given situation or the complete accuracy of a suggestion made by someone else.

My orginal question referred to a full approach clearance given with the intercept heading. Perhaps our brains will have to leave the confines of the UK to discuss this further as I realise that "Cleared ILS approach runway XX" is rarely used in this country. It is quite clear to me that a clearance such as (quotable inaccuracies probable) "turn left heading xxx, closing the localiser from the left, report established" does not constitute a clearance to do anything other than turn to the heading and establish on the localiser.

To pose the question again:

Let's assume we're outside the UK then, we're given intercept heading and cleared for the ILS approach at the same time. We are not yet established on the localiser or any other published segment of the approach procedure or it's associated transitions. Is there any case where ATC will expect you to descend to the published platform altitude (or any other altitude for that matter) at this stage?

CP

[vector4fun]

Let's assume we're outside the UK then, we're given intercept heading and cleared for the ILS approach at the same time. We are not yet established on the localiser or any other published segment of the approach procedure or it's associated transitions. Is there any case where ATC will expect you to descend to the published platform altitude (or any other altitude for that matter) at this stage?
CP
OK, in the U.S., you'd be specifically given an altitude to maintain until established on the approach:
"N12345, XX miles from (FAF), turn left heading 190, maintain three thousand until established, cleared ILS 17 left approach"
Unless you were already established on a published transition route to the final approach course. In which case, the clearance could simply be:
"N12345, cleared ILS 17 left approach."
Once established on the localizer, you could legally descend to any published intermediate altitude until glideslope intercept.

[FlightDetent]

Not in your exact scenario.

We are not yet established on the localiser or any other published segment of the approach procedure or it's associated transitions.

Obstacle clearance is pilots' responsibility. If you cannot judge, maintain last assigned altitude me thinks.


FD.

[Haul By Cable]

It seems that due to the lack of a definitive publication regarding R/T for Air Transport, confusion in this area is not uncommon.

I have experienced numerous scenarios in mainland Europe where confusion has occurred, one of my least favourites being Girona.

I'm not sure that the UK ATCOs can really help as it's not them that find themselves flying into these airports and being on the receiving end!

[Inverted81]

Hi just to add something to the mix...
Am i correct in assuming that the pilot COULD descend tho the MDA/H at any point on the approach as long as terrain/obstacle clearance is maintained. Are we only looking at this situation however on a visual/ intrument to visual approach?

I would expect the pilot in the normal situation to maintain his altitude until established on the LLZR unles given specific insructions to descend earlier by the controller. After all part of the responsibilities ,if in normal procedures, is to initially intercept the arriving aircraft below the Glidepath....

shoot me down in flames if you like... :ok: :E :sad:
81

[Plumaveloz]

In Spain the R.C.A. (the Law[:)]) states that, when in radar vectoring, the last given one should be so that the pilot at a given altitude will intercept the localizer two miles before the glide path "force" him to descend.

Our usual clearance is:

ATC: "XXX-####" left/right heading ###, final vector, cleared for ILS app, rwy ##"

And we expect piltos to follow the heading to intercept and follow the localizer and once established, to descend acording glide path. We understand that an ILS clearance gives both heading and descend procedures.

Very often, we find that brit pilots ask for further descend once established, that we understand is given on the ILS clearance, and many of them also report that, what we most of the times do not need to know, but also use that communication to transfer the plane to the tower.

To avoid this, we use this phraseology:

ATC: "XXX-#### left/right heading ###, final vector, cleared for ILS app, rwy ##, descend acording procedures/at pilot discretion"

To the spanish pilots and other, ILS clearance makes them descent.

Regards from the sun:D

A.

[Plumaveloz]

... confusion has occurred, one of my least favourites being Girona.


I have some colleagues there. Please, give us an explanation of the matter, and I´ll ask them for some facts

Regards,

Á.

[captainpaddy]

Plumaveloz,

As you are working in ATC in Espana:

Just to confirm that you would not expect an aircraft that is cleared for the approach to descend below the last cleared level until established on the localiser? I think you may have answered my question!!

Regards,

CP

[Plumaveloz]

Plumaveloz,
Just to confirm that you would not expect an aircraft that is cleared for the approach to descend below the last cleared level until established on the localiser?

Correct, with one exception: Requesting visual approach just a little before established on the localizer, or even once established, in order to descend below minima.

Á.

[Spitoon]

This is a fascinating question that never seems to go away.

First, to answer captp's original question - and I offer my input for a UK controller's perspective - I would not expect a pilot to descend below the last level that I had assigned until established on the LLZ (and, for the really pedantic amongst us, given a clearance to descend on the ILS). But I would be alert to the possibility that a pilot might descend simply because of the differences of opinion being expresed in this thread.

It has happened to me on a handful of occasions over 20-odd years of controlling - sometimes it matters, and I've had to do something to ensure separation from other traffic, other times there has been no traffic problem and my only concrnn has been that the aircraft does not descend below terrain safe level. It's not an ideal situation but I recognise that I'm not going to change it so I try to find ways to live with it in the best way possible - so I won't bother getting into the debate about who uses the 'right' phraseology! Except to say that unless pilots have a consistent understanding of the meaning of a standard phrase, standard phraseology offers few benefits.

On a more general point, I think the question that captp asks highlights a distinction that is probably clear to controllers but seems to be blurred in pilots' minds. If an aircraft is under radar control and I'm giving vectors, I am responsible for assigning levels that are terrain safe and for pointing the aircraft in the direction it should go (accepting, of course, that the pilot-in-command is always ultimately responsible for ensuring the safety of the aircraft). This is why, when vectoring to the ILS, I expect the aircraft to fly at the levels that I specify - which will include a clearance to descend on the ILS when it is appropriate given the traffic situation.

If I am controlling without the benefiit of radar, the pilot is responsible for remaining terrain safe. I will give a clearance that is valid at the relevant fix - safe from other traffic all the way that the clearance covers and terrain safe at the fix - how the pilot gets to the fix, subject to any restrictions that are included in the clearance, is up to him or her. In this circumstance, when I clear the aircraft for the ILS procedure, I expect the pilot to follow the procedure track and to assur that the aircraft remains terrain safe. The approach procedue will define minimum levels to be flown at various points in the approach and I understand that the pilot may choose to desend to the specified level immediately or, alternatively, may elect to manage the descent profile to give a continuous descent where this is possible.

As a controller, the distinction between the two types of ATC service - and the procedures that pilots should follow - is very clear but perhaps this is not the case from the pilot's seat.

[captainpaddy]

Great post Spitoon.

My impression from this post and another similar question in the Tech Log forum is that what yourself and our Spanish ATC friend have said is what I had expected to be the case. It does seem that we pilots decipher certain situations we find ourselves in and become confused as to the actual legal requirements and/or expectations.

In my mind I feel happier that we should be maintaining the last assigned level until established on the localiser or segment of the approach before commencing further descent, assuming we have already been cleared for the approach. At the end of the day if we need lower we should ask for it, and if we're not sure if we're already cleared we should ask for clarification!!!

Many thanks guys & gals,

CP

[FinalVectors]

Let's assume we're outside the UK then, we're given intercept heading and cleared for the ILS approach at the same time. We are not yet established on the localiser or any other published segment of the approach procedure or it's associated transitions. Is there any case where ATC will expect you to descend to the published platform altitude (or any other altitude for that matter) at this stage?
CP
Hi!
How I see this is as follows.
If I clear you for a ILS on own nav, (I.e Straight in approach..direct to FAF). You are theoretically cleared to descend as well according to the procedure. (Even if you are under radar control, as long as you make "your own intercept"...its kind of like U are following "old time" procedural control. So because of that you can also descend). But for all practical purposes, you would most likely get something like "Maintain 4' until GP."

But If you are on a intercepting VECTOR, you are not to descend before you catch the GP unless told by ATC.
I allways specify this with i.e "turn left hdg xxx, mainatin 4' until established, cleared ILS rwy XX)

There might also be some other reason why ATC dont want you to automatically descend. I.e if you working at a busy airport with 3nm spacing..you need sometimes to be closer than 3nm when you start the final turn to get 3nm on final. (You lose distance in the turn) So in this case you need to maintain vertical sep. in the turn when you give the ILS clearance. (Which means you will intercept the ILS 1000ft above your preceding acft.)

My experiences are from Norway, but guess it should be mostly the same all around Europe at least.

Regards
Final Vector

[Bern Oulli]

Bear in mind also the protected range of the glidepath - normally 10 miles in the UK. If you are above 3'000' aal then you should not be using the glidepath indications as you are very probably outside the protected range. (4'000' aal equates to approximately 13 miles from touchdown on a 3 degree g/path.)

[captainpaddy]

Bern Oulli,

Fair point. Not many people realise this when they catch the glide from a long way out.

FinalVectors,

Thanks for your post. I think your last point is the most important. ATC will always have the bigger picture. What has propmted me to create this thread is that I felt arbitrary descent before localiser capture could be potentially dangerous with respect to other aircraft even if a possible terrain problem is confirmed as not relevant by the crew.

CP

[FinalVectors]

CP...
You also have to take in to account lower limit of controlled airspace.
Here in Oslo, we even have put a restriction on descend on Visual approach becasue of some nearmisses between IFR traffic and GA traffic flying "+- 10 feet" from the lower limit of our airspace (C airspace to 3000, and G airspace below. So a coupe of times we had GA traffic at "2999feet" and IFR on VA at 3000feet....Noone did anything wrong..but they got fairly close) As a result of this (even if its pilots responsibility when he is on own nav/VA)...in that sector we now allways restrict VA to 3500' until they clear of the area.

To realte this to your case...if you descend when cleared ILS, you may come very close to..or below the limit of controlled airspace in some areas.
So good advice is...if you are in doubt..ask the controller before doing anything :)

[drag required]

If cleared for the “approach”(straight in) maintaining 4000 feet and the initial approach altitude is 2500 feet, once established inbound (half dot, 5 degrees, PAP or NPAP) you can descend to the initial approach altitude of 2500 feet unless you have been instructed to maintain 4000 feet until the glide. You are cleared for the approach and you haven’t been told to maintain 4000 until the glide, so why should you maintain 4000 feet, you are protected by an initial approach altitude plus you are cleared for the approach. It is the case in the UK that they clear you in parts, first the localiser and then the glide, but in other countries the clearance only states the ILS in which case there is no need to maintain the last altitude flown in the intercept leg, i.e. Madrid 25 miles out at 9000 feet. Many UK pilots in non UK destinations seem puzzled when cleared for the ILS and then ask if they can descend on the glide path, if you are cleared for the ILS you are cleared for the whole thing and if you are established inbound you can descend to the initial approach altitude and intercept the glide later, as long as you don’t breach the minimum descend altitudes in the straight in approach profile and ATC didn’t say otherwise. Correct me if I'm wrong, cheers…..:D

[foghorn]

Maybe since "maintain altitude x feet until established, cleared ILS approach" seems to work in more than one other country, it's time that the UK removed its two-part ILS clearance and standardised on this?

It achieves the same ends in preventing an early descent as the usual two part "report established" ... "descend on the ILS" clearance and is less of a mouthful than the new single "when established on the localizer, descend on the ILS" clearance.

[chrisbl]

Just returning to the US for a moment there is a mnemonic used called PTAC

Position from the fix ie "5 miles from KATHY"
Turn heading 260 to Interncept localiser
Altitude : maintain / decend to 3000 ft until established
Clearance : cleared for the ILS 29 ......

Thats it. Once established the ILS is flown as written and the only other clearance required is "cleared to land" after the handover to the Tower Controller.

It cuts down the chat on the radio but leave you dead clear about where you are and what you can do.

[chevvron]

Foghorn: totally agree; I think you'll find some of the busier airports will be doing this soon if not already.

[dunadan06]

From a french RCA (law) point of view, this is not the type of clearance you should get.
It should be something like: "Callsign, turn left heading XXX to intercept LLZYY, report established"
Once established: 'Callsign, descent altitude zzzz ft, clear ILS approach Rwy YY"
The 2 can be in one message: "Callsign, turn left heading XXX to intercept LLZYY, when established, descent altitude zzzz ft, clear ILS approach Rwy YY"
Obviously the "descent" part wan be removed if you're already at the published altitude ti intercept the GP :)
Anyway, if you get the message you were talking about, just keep in mind that (at least) in France, when you're under radar vectors, the ground clearance is provided by the ATC.
As this vectoring ends once you're established on the LLZ (or VOR radial...)of the procedure, you should NOT start your descent before being established on the LLZ. Then, you're on your own, you can descent to the published altitude, or follow the glide when you find it ;)
I don't know if it's of any help to you, but just remember: You can still ask the ATC if you're clear to descent:O