Descending once cleared for approach
 

My first post, here goes. On a recent Europe trip, we were descending to FL 80, proceeding as directed to an iaf at a French airport. Then we were cleared for the ils approach. Is it ICAO procedures that further descent levels or altitudes are up to the pilot (for eg, 25 mile MSA)? Is there any online documentation that details this, similiar to the US AIM?

The details were LFOK, Vatry Chalons, France, Ils Z RWY 10, iaf was KELON

Spud3

Yep that is how it works. Don't have a reference to hand at the mo. Once ATC have cleared you to the IAF then making any intermediate step/check altitudes, config changes, speeds and terrain avoidance are all down to you. A good example would be the ILS onto R13 at LEMG. ATC will clear you to either a FL or altitude and clear you for the approach. There is significant terrain on the approach and hence a stepped descent until the latter stages where you pick up the glide. We would arm the localiser and lock onto that about 25nm out or so and then step descend to the final platform altitude before arming the glideslope to ensure terrain clearance.

Yup, it sounds like from what you said that altitude would be at your discretion. If you were cleared for the Arrival into the airport you could follow the flight path for the arrival but you can't descend to the chart altitudes until ATC either clears you down to them or clears you for the Approach. So if you were on an Arrival and then got cleared for the Approach, you could descend down to the minimum altitudes on the Arrival chart, as well as the other minimums you mentioned such as MSA as you come to them.

MSA is not relevant IF you are ON a published approach path and you observe the published minimum altitudes. MSA represents clearance on the highest obstacle in the sector and will be higher than published approach restrictions. However, fly OFF that published approach eg take a short-cut........................

In my situation there was no arrival. Originally we were enroute, I think direct the airport or the vor on the field. Then atc gave us direct the iaf.

Potkettle, I looked up your example, however it is for proceeding FROM the iaf. Mine is TO the iaf, where there were no "intermediate step/check" altitudes that you described. So....I see no option for me except the 25 mile MSA, which is not centred on the IAF.

Italia, I was not on an arrival, and atc did not give me any descent, just cleared for the approach, while I was at FL 80. So am I correct to wait until within the 25 mile MSA and then leave FL 80?

BOAC, what is really interesting is that the MSA within 18 miles is 2100 feet, while the altitude past the iaf at 11 dme while inbound to the field is still 2500 feet. Any idea why?

If you are cleared direct to the IAF and cleared for the approach, YOU MUST MAINTAIN LAST ASSIGNED ALTITUDE UNTIL YOU REACH THE IAF!!! Since you are not on any published procedure, you must adhere to your ATC clearance.

Where does it say ANYWHERE that while on a vector you can descend at your discretion without further clearance?!? I've never heard of that one!

Intruder, I wasn't on a vector, and "maintain last assigned altitude" til on a portion of the instrument procedure **I think** might be a USA only requirement. Not sure.

Where does it say I can descend to MSA once cleared for approach? Don't know, that's why I was asking those who know French/ICAO procedures

And a reference to an online AIM type ICAO document.

Surely common-sense applies here anyway? If in doubt ask ATC. Tell them what you are doing as well - this helps other traffic.

Spud - I guess 2100 was unnecessarily low at 11D? 2500 about right for 2.5 slope?

Mig3, we were in descent to FL 80 and told to proceed direct to an iaf, and we were not on an arrival. Immediately after that we were cleared for an approach well before reaching the iaf. In Australia then, is MSA included as one of those altitudes you are now cleared to descend to once withing the specified distance?

Its real simple, if cleared the apch, you do just that, ensuring when doing so you dont bump into anything solid. Last week when sixty miles back from destination it went like this"CG XXX, cleared out of controlled airspace for the apch into CYXXX," now there are some big lumps of rock around this particular place, the controller presumes you have charts giving the MEA and wont try to move one with the pointy end of your aircraft. Lets not complicate things.leave that to the nerds on the groundspeed thread!

As a French ATCO I'd say you take up the IAC chart and look at the altitude restrictions following the IAF. Since there only is the G/S capture at 2500ft, you can descend until 2500ft at convenience according to the rules for direct arrivals (and not STARs), which means you do not get below the MSA, inside the 25NM sectors centred on CAV. And if you're further than 25D from CAV, then it's FL80 minimum.

If there had been a level restriction at KELON on the chart then you would have had to stop descent at that level (or adjust descent rate to be above it at KELON...).

Radar vectors are what they are, that is to say headings to follow. If on a direct to a fix, it's no longer considered vectors. Since you're not on a specified route, the ATC will clear you at or above the minimum safe radar altitude of the sector, which usually is lower than en-route charts.

But in doubt, ask over R/T...

You were cleared to a fix, descend to 8000. Do that.

You were then cleared for the approach. The fix to which you are currently cleared happens to be the IAF. Your clearance before the approach has not changed. Proceed direct to that fix, descending to 8000. Descend from 8000 only after established on the approach (i.e., passing the IAF) or specifically cleared for lower by ATC.

I have not seen any rules written anywhere that are different from the FAA rules. What have you seen WRITTEN that gives you the impression you can descend below 8000 enroute to the IAF when only cleared to 8000?

I don't have the charts right now so I can't say for sure but if you are cleared for the approach you do not need further clearance to descend. You do still need to follow the minimum altitudes that are on the approach chart and the other IFR charts. If you're already at the lowest altitude for your position then you can't descend.

Cleared for arrival = cleared for the path dictated on chart, do not descend without clearance

Cleared for approach = descent at your discretion while adhering to the altitude restrictions on your "path" and cleared to fly the arrival "path".

Once again, do not confuse clearance to descend ON THE APPROACH -- either after passing the IAF or after intercepting the approach course inside the IAF -- with descent PRIOR TO the approach. There is no inherent "clearance" to descend any further than the explicit ATC cleared altitude when being vectored to the approach course or when cleared direct to the IAF or a fix inside the IAF.

Descent on a STAR or other published arrival route is different, and a clearance may be given to "descend via" the arrival, including altitudes. Clearance procedures and phraseology differs among US, UK, and the rest of the world, though, so make sure you know what your clearance means.

MSA is for emergency and lost communications reference ONLY.

I don't understand the confusion here. If ATC clear you direct to the IAF and whilst routing there you are cleared for the approach you may descend in accordance with the approach once established on it. However, you are not on the approach until you reach that IAF. Any descent below that FL80 needs a specific ATC clearance. If FL80 is too high to intercept then you need to request lower. The only other way around it (assuming weather permits) is to request a visual approach. Surely it is no different to being cleared for the ILS whilst on an intercept heading and realising that your last cleared alt will be too high to intc the GS. I know plenty will just wind the MCP alt down a coupe of hundred feet to make it work but I think everyone would agree that is not strictly correct.

In the circumstances you have described assuming you needed a lower FL/alt to make the approach work surely you ask for descent or at least clarification of the clearance, and not simply descend the MSA without talking to anyone about it first?

Spud3 asked a straightforward question about procedures while undertaking an arrival into a French airport.

There are two relevant sets of procedures here. The definitive ones are French. JeeHell has answered, self-identifying as a French ATCO. If what he says requires confirmation, I can ask another colleague to contribute who is a French ATCO and also on PPRuNe.

The second set of procedures would be those agreed through ICAO. It is interesting, as always, to find out where these might differ from local (here, French) rules. I don't know. Anyone?

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.

PBL

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


LFOK Chart
Looking at the chart, 2 interesting things:

1. If you overfly KELON at FL80, then you're up (or down as you wish :rolleyes:) for some turns before you reach the compulsory 2500ft at the IF. Or you have good S/B... So what is the point in clearing for approach as early prior to KELON as Spud3 describes?
2. Entry protection of hold at KELON is 5000ft pressure altitude. So if you start holding at FL80 you may end up in an other airspace, so I'm pretty sure standard local instructions are to clear at least down to 5000ft if holds are expected.

I'd say the ATCO might have been a bit lazy, from what I can picture from the situation, I would have cleared the ACFT down to 5000ft in the same message as the approach clearance, in order to clear any ambiguities...(here 2500 would have even been ok, I think the minimum radar altitudes in the area are lower than that even 25NM away from CAV)

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

Fly safe,

PantLoad

It always amazes me that in all the reams of ICAO documents, including standard phraseology for clearances, there appears to be nothing that tells pilots what the words actually mean. There is no equivalent of Section 5-5 of the FAA AIM.

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.

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.

Those who referenced "intermediate/check altitudes", "stepped descents", "platform altitudes", chart altiitudes", "minimum altitudes", "common sense", "mea", "altitude restrictions" unfortunately for me did not give me a clear answer.

My thanks for Intruder for at least coming forward and giving his answer, a definite NO.

Jeehell seems to say YES I can use the MSA once cleared approach.
Ast83 seems to say no.
PBL, yes, please ask your colleague for his input.
PantLoad, the TWA aircraft was well below any safe altitude. No one is suggesting that.

.

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?

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.

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?

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.)

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.

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.

>>>(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...)

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)

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..

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.

italia458

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

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!

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

If true, where is it written?

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

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

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?

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.

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.

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.