Descending once cleared for approach

[spud3]

In the UK it is generally believed by ATC that a clearance for an approach permits the aircraft to descend immediately to the charted altitude at the IAF. This is the excuse normally given for the UK anomalous phraseology for ILS approaches

.

Bookworm, are you suggesting that atc is meaning descent at pilots discretion? If so, are pilots then permitted in the UK to use the MSA in determining their safe altitudea?

[flown-it]

use VNAV

If I were doing this I would put 5000 as a "hard" altitude at KELON and go direct to the fix. Ensure LNAV is the active mode, set the MCP alt to DA and arm VNAV. I would then get a TOD at about 5 miles from the fix (approx 3000 ft to loose from FL80) which would be well within the MSA 25.
I would allow LNAV/VNAV to make the turn to final and since you have DA in the MCP, VNAV will cross the IAF (KELON)at 5000ft but in a descent allowing you to arm the approach and get a LOC and G/P capture.
I don't have the chart so I don't know the distance between the IAF and the FAF. Depending on that, VNAV may well level you at 5000 until you reach the G/S outside the FAF.
And NO you are not capturing the G/S from above you are capturing it further out but from below.

[spud3]

Flown-it. Thanks but I wasn't looking for aircraft flight director handling techniques or equivalent. I was looking for a yes, or a no. And, preferably, an icao reference.

Surely there must be an icao doc similar to the US AIM.

Anyone?

[bookworm]

Not in the U.S.....There was a TWA accident at Dulles (IAD) several years ago...

Synopsis.

(I was puzzled that I couldn't find this at first, as I also remembered it as IAD -- the database has the destination as DCA, but the synopsis clearly shows the destination was Dulles.)

Thanks for the replies. As the OP, please let me reinterate that the ONLY question I had was on whether it is permissable in France to descent to the 25 mile MSA altitude when off airways/route but cleared direct to an iaf and cleared for approach.
...
Bookworm, are you suggesting that atc is meaning descent at pilots discretion? If so, are pilots then permitted in the UK to use the MSA in determining their safe altitudea?

The MSA has nothing to do with it. Nor has pilot's discretion. It is absolutely clear (PANS-ATM 8.6.5.2) that ATC is responsible for terrain separation when giving a vector or a direct clearance. The issue is whether the clearance for an approach includes an implicit instruction to descend to the initial altitude for the approach.

FAA AIM 5-5 deals with the issue explicitly:

Pilot
3. Upon receipt of an approach clearance while on an unpublished route or being radar vectored:
...
(b) Maintains the last assigned altitude until established on a segment of a published route or IAP, at which time published altitudes apply.

Controller.
...
2. Issues an IFR approach clearance only after the aircraft is established on a segment of published route or IAP, or assigns an appropriate altitude for the aircraft to maintain until so established.

AFAIK, ICAO does not offer guidance.

[spud3]

While the FAA deals with it explicity, so do Canadian authorities, although in an opposite way.

Jeppesen Airway Manual, Air Traffic Control, State Rules and Procedures, Canada
clearance for an approach may not include any intermediate
altitude restrictions. The pilot may receive this clearance while the aircraft is still a considerable distance from the airport, in either a radar or non-radar environment. In these cases, the pilot may descend, at his/her convenience, to whichever is the lowest of the following IFR altitudes applicable to the position of the aircraft:
a) minimum en route altitude (MEA);
(b) published transition or feeder route altitude; or
(c) minimum sector altitude (MSA) specified on the appropriate instrument approach chart.
emphasis mine.

[italia458]

While the FAA deals with it explicity, so do Canadian authorities, although in an opposite way.

Jeppesen Airway Manual, Air Traffic Control, State Rules and Procedures, Canada
clearance for an approach may not include any intermediate
altitude restrictions. The pilot may receive this clearance while the aircraft is still a considerable distance from the airport, in either a radar or non-radar environment. In these cases, the pilot may descend, at his/her convenience, to whichever is the lowest of the following IFR altitudes applicable to the position of the aircraft:
a) minimum en route altitude (MEA);
(b) published transition or feeder route altitude; or
(c) minimum sector altitude (MSA) specified on the appropriate instrument approach chart.
emphasis mine.

spud3... that is correct. I know Transport Canada has their AIM posted on the website. I'm guessing that the French aviation authority would have some site and possibly it's regulations posted there as well.

I fly in Canada and can confirm that Jeppesen quote. Intruder is incorrect, I've never heard of the MSA only being used for emergency. You're required to follow all altitudes on your charts appropriate for your flight (including the MSA) unless on radar vectors where you might be taken lower than the lowest published altitude.

[SeniorDispatcher]

>>>(I was puzzled that I couldn't find this at first, as I also remembered it as IAD -- the database has the destination as DCA, but the synopsis clearly shows the destination was Dulles.)

TWA514 was a scheduled CMH-DCA flight that diverted to IAD due to crosswinds at DCA.

ASN Aircraft accident Boeing 727-231 N54328 Upperville, VA

(NTSB AAR link at the bottom of the above page...)

[JeeHell]

All French AIP is viewable online on SIA - La référence en information aéronautique
On the left column, look at the items French Regulation (only in french afterwards though) and AIP-Charts (which will give both charts AND the En-route manual which I already quoted in my previous post link. In EN & FR)

[johns7022]

Some years back I left Kalispell, MT at night for this little airport just South of the Arctic Circle.....the first thing that struck me was the lack of radio chatter, hardly any lights down below, then about 200 nms out they said 'Cleared for any approach at 'X' airport'

So I am sitting there...a whopping 2500 hrs of flight time, scratching my head at how I was going to do this...

Needless to say I considered flying to the IAP, at 14000ft, then circling down(lol)..that would be the safe thing do for for sure...then I took a look at the MEAs..got down to one of those..then found the MSA..got down to that..crossed the IAP at the published ALT....then did a full instrument approach.....It's easy if the aiport has a VOR but if you get down to an MEA...flying to an NDB...MSA seems the way to do it..

[Type1106]

I believe there is some confusion here when discussing MEA and MSA.

MEA is defined as 'Minimum en route altitude (MEA) is the lowest published altitude between radio navigation fixes that assures acceptable navigational signal' and I don't think this has anything to do with a clearance direct to a terminal fix in the circumstances being discussed in this thread.

Depending on distance from the IAF the considerations must surely be your safety altitude for that portion of the route and then the 25nm MSA.

Finally, if in doubt that you've been cleared out of the last assigned altitude - in this case FL80 - then ask ATC.

[galaxy flyer]

italia458

Intruder is incorrect, I've never heard of the MSA only being used for emergency.

There is a difference between US and Canada on this one--the FAA TERPS says that the MSA is for "emergency use only", it is not an operational altitude. One reason, in the US the MSA is not surveyed for signal coverage, nor does it guarantee it. Also, from a US Terpster, the MSA is not resurveyed unless there is a change in the basic procedure, hence, there is a possibility that an unsurveyed may exist in the off-route areas.

That is one reason why US ATCOs give the approach clearance with specific altitude instructions. Well, one of the reasons, those ATC instructions all came from the TW 514 accident.

That is US only, other countries have other ways of applying the MSA.

GF

[Intruder]

Third, it is not clear to me that Intruder yet comprehends that not all procedures everywhere are the same. Not even in adjacent countries in Europe.

If I didn't comprehend, I wouldn't have cited the VERY RECENTLY CHANGED differences in arrival procedure differences in the US and UK.

However, NOBODY here, including the French ATC, has offered ANY evidence that a descent below the already-cleared altitude/level is allowed on a direct-to clearance PRIOR TO the IAF. The exception for "cleared for approach" in Canada cited above is interesting, though I suspect it is used more in remote locations than as a routine procedure for airline operations into major airports.

If you have citations to show otherwise, please post them!

[Intruder]

ENR GEN 1.7 : Differences betweew ICAO and French Regulations
Good luck browsing that file

I did. There are no differences from ICAO procedures cited for descent clearances.

[Intruder]

In the UK it is generally believed by ATC that a clearance for an approach permits the aircraft to descend immediately to the charted altitude at the IAF.

If true, where is it written?

[PBL]

Originally Posted by spud3

PBL, yes, please ask your colleague for his input.

I did. He is away from posting until the end of the month, but if you can remind me again then I'll remind him.

PBL

[PBL]

Originally Posted by Intruder

[PBL: it is not clear to me that Intruder yet comprehends that not all procedures everywhere are the same....]
If I didn't comprehend, I wouldn't have cited ...

Thanks for clarifying. Per your request for citation, I just looked it up in Giemulla (the "Frankfurt Commentary", standard text) without success. I don't know where it is. I can ask.

PBL

[bookworm]

n the UK it is generally believed by ATC that a clearance for an approach permits the aircraft to descend immediately to the charted altitude at the IAF.
...
If true, where is it written?

If it were written somewhere I could find, I wouldn't have said "it is generally believed". However, this is from the CAA's CAP413 supplement

"‘Cleared ILS approach’ may introduce an element of uncertainty as to when descent will be initiated because the pilot may descend to the final approach point altitude (platform height) at any time after receiving this clearance.’

There are also many threads on PPrune about the non-standard UK phraseology in which this aspect is discussed.

I believe that both interpretations are reasonable ones (without further clarification as in the AIM).

A clearance for the approach is an instruction to follow the vertical profile of the approach without further ATC instruction. Descent to subsequent levels is implicit. Why should that implicit vertical profile not start at the IAF with the charted altitude there?

Another example: I'm being vectored for an ILS at 3000 ft, a level above the charted FAP altitude of 2400 ft. The controller says "closing the localiser from the left, cleared ILS approach runway xx". I intercept the localiser and the glideslope comes in 2 miles before the FAP. May I descend? By your reasoning, I'm not on a published segment of the approach yet, so don't I have to wait until I reach the FAP before descending?

[ast83]

Of course you can. At 3000ft were cleared for the approach so once you're established on that approach you may descend with it. I think the more relevant question for the OP would be, can you descend to that 2400ft platform once cleared for the approach, perhaps even whilst still on an intercept heading?

Spud3, I understand you simply want to know if it's permissable. My common sense tells me it's not but it seems, I may be wrong. In the uk we are often cleared for the localised RXX, whenvestablished descend with the the GS. I always thought this was strange phraseology. Why not simply say cleared approach? Surely it's the same thing? Maybe this thread holds the answer, maybe a clearance for the approach does clear you to descend at your discretion implicitly. I'm yet to confim it either way. I'll continue the search.

[bookworm]

At 3000ft were cleared for the approach so once you're established on that approach you may descend with it.

Nope, you're not established on a published segment of the approach.

"The final approach segment begins at the final approach point (FAP). This is a point in space on the final approach track where the intermediate approach altitude/height intercepts the nominal glide path".

You're two miles further out than the FAP, and therefore not on the published final approach segment.

Of course, every pilot would descend on the glide, and every ATCO would ensure that such a descent was terrain-safe -- not difficult in this case, but it could create an issue at the extremity of coverage. I'm just pointing out that there are occasions when there is an implicit instruction to descend -- and spud3's case is arguably one of them.

[JeeHell]

maybe a clearance for the approach does clear you to descend at your discretion implicitly

I wouldn't go that far.
My reading of the text is when cleared for approach, you are cleared to descend while still observing the higher of MSA and approach altitude restrictions. After the IAF for sure at least (see second part of the post for before the IAF...).
In Spud3 case, the MSA is 2700ft in the north east until 18M then 2100ft everywhere else. The initial and intermediate approach are published at 2500ft. So, you may only descend to 2700 then 2500ft or 2500ft directly (depending on your arrival sector) and never below until you pass the FAP.

After thinking a lot about it, in this particular case I'm pretty sure the ATCO implicitly allowed further descent (to confirm, Spud3, it would be great to tell us what where your following actions and interactions with ATC).
Now in a more standard way, I'm pretty sure the approach clearance should come with a level/altitude UNLESS the last assigned level/altitude is compatible with the approach profile (meaning you won't go below that level before somewhere between the IAF and IF because of restrictions). Here FL80 is clearly not compatible since at KELON you should be FL050 max.