View Full Version : ATC speed after approach clearance
27th Jun 2012, 09:10
Gents, not meant to stir-up anything here.
Had a discussion the other day what happens to an assigned speed after approach clearance received if the speed requirement is not repeated after the clearance.
I was under the impression that I have learned as an ATCO student maaaany moons ago, that after approach clearance speed is up to the pilot unless stated again (eg. cleared ILS approach maintain 160 till 4NM). I have browsed ICAO doc4444 and 8168 with no luck. Anyone with a valid reference?
Now sitting on the other side of the radio transmission (traitor, I know... ;) ) of course good airmanship dictates that I say when I reduce speed, but I thought I could just do it.
Thanks for inputs
Well cant give you any reference but if I issue speed control and then clear you for the approach, I expect you to comply with that speed until I tell you otherwise. If you need to reduce, tell me!
My analogy would be compared to if I give you descend to 3000 feet and then clear you for the approach, my instruction is still valid to descend to 3000 feet, you cant just stop at 4000 feet until the glidepath because I have now cleared you for the approach.
27th Jun 2012, 13:19
Sorry I'm not well versed in many ICAO documents, but in for US controllers it's found in the 7110.65. 5-7-1
d. Approach clearances cancel any previously assigned speed adjustment. Pilots are expected to make their own speed adjustments to complete the approach unless the adjustments are restated.
and also the AIM for pilots 4-4-12
f. If ATC determines (before an approach clearance is issued) that it is no longer necessary to apply speed adjustment procedures, they will inform the pilot to resume normal speed. Approach
clearances supersede any prior speed adjustment assignments, and pilots are expected to make their own speed adjustments, as necessary, to complete the approach. Under certain circumstances, however, it may be necessary for ATC to issue further speed adjustments after approach clearance is issued to maintain separation between successive arrivals. Under such circumstances, previously issued speed adjustments will be restated if that speed is to be maintained or additional speed adjustments are requested.
27th Jun 2012, 13:40
Unless the speed restriction is repeated or revised, an approach clearance cancels any previous speed restriction and is now at the pilots discretion.
27th Jun 2012, 13:51
Thanks both for the answer...
Rusty, that is how I have it in mind as well... But I cannot find the reference anymore.
ASD, I know that you expect me to do that, that is why I do or advise if unable. That's the practical side of it. But what is the legal background. I know it's a bit academic...
Pg 258 Appendix 5 Table A5-6
113 REDUCE SPEED TO (speed)
Instruction that the present speed is to be reduced to the specified speed and maintained until further advised.
27th Jun 2012, 14:48
ASD thanks again. Yep, I am aware of this... But what I am looking for is, what happens after I get the cleared for approach. What if you forget to release the speed control and send me over to TWR...
For example you are responsible for terrain if you take me on radar vectors. Once I am established on ILS/VOR/NDB/Visual I am responsible for terrain again.
As said initially. I am referring to something I believe I have learned some 20 years ago...
I would also be keen to see anything written that specifies that an aircraft can fly their own speeds after being cleared for the approach.
I will keep a keen eye out on this thread as I do believe many pilots are under this impression but a lot of ATCO's - myself included are certainly not under this impression at all.
27th Jun 2012, 15:09
The answer also could be found in states AIP. Here is extract from ours :
These speeds are applied for ATC separation purposes and are mandatory. Aircraft unable to conform to these
speeds must inform ATC and state what speeds can be used.
In the event of a new (non-speed related) ATC instruction being issued pilots shall continue to maintain the
previously allocated speed. All speed restrictions are to be flown as accurately as possible.
Non-compliance with speed control instructions may lead to an aircraft having to be executed from the planned
Duke of Burgundy
27th Jun 2012, 15:46
When I was an ATCO at Heathrow several years ago I had a minor incident caused by an American pilot doing exactly this ie flying his own speed down the approach because I hadn't restated it.
Have a look at this http://www.faa.gov/air_traffic/publications/atpubs/atc/atc0507.html Items 4 c and d refer.
27th Jun 2012, 16:06
Not yet been mentioned:
220.127.116.11 Speed control should not be applied to aircraft after passing a point 7 km (4 NM) from the threshold on final approach.
27th Jun 2012, 16:13
Duke, thanks! That is the exact wording I was looking for... However, I was under the impression that it was the same in ICAO. I did my ATCO training in Europe as well and didn't know anything about FAA regulation.
@<hidden>: I agree, it can be stated in CRAR or AIPs as well. My problem is that I cannot know all the special procedures of the 100 odd possible destinations we fly to.. But this is worth another discussion ;)
But then again... we are professionals and should work and talk together. And as my old ATC instructor used to say (valid for both sides!!) Never ASSUME... it makes an ASS out of U and ME...
27th Jun 2012, 17:27
Interesting discussion. Had the case recently that i was cleared for the ILS out of 6000ft instead of 4000ft and of course reduced speed during G/S intercept to achieve the initial approach configuration. As we were quite busy we forgot to tell ATC about the speed reduction and got a pretty strict sermon shortly afterwards. However, remaining at 220kts while on the G/S is simply impossible, the aircraft would accelerate if not configured and that would lead to a go around very shortly afterwards. To configure we need to reduce speed, so it is pretty much basic aircraft performance 101 that G/S intercept will lead to a speed reduction. By the way, no further speed control was given with the approach clearance, last speed given before was 220kts in a 738 and the usual 10 to 15 kts tailwind one encounters in ZRH at that altitude.
27th Jun 2012, 18:05
I your case, the answer is in Swiss AIP REF ENR1.5 LSZH AD 2-43 2.5.3
Speed restrictions are applied for ATC separation purposes and are mandatory. In the event of a new (non-speed related) ATC clearance being issued (e.g. an instruction to descent on ILS), pilots shall continue to maintain a previously allocated speed. ....
27th Jun 2012, 19:36
isn't it this simple? at some point an airplane must be slowed to what is its normal approach speed in its normal approach configuration.
ATC should understand this...and it is especially important when the wx is near approach minimums.
IT is custom in the USA to speed restrict to the marker...after tha point it is reasonable to slow down.
And in the final analysis it is incumbent upon the pilot to only accept a clearance he can comply with.
Also, in the USA, it is first come first served...if you are number on on the approach, it would be the rare circumstance to make YOU go around for faster traffic above you and behind you.
28th Jun 2012, 06:57
What goes up...My problem is that I cannot know all the special procedures of the 100 odd possible destinations we fly to..
Personally I find that statement a bit worrying. OK, I don't expect you to know the procedures at, say, Madrid, when operating a flight from London to Stockholm, but I would expect you to be briefed on procedures at London, Stockholm and enroute between the pair. i.e. propely briefed for the flight you are operating. Is that not what a pre-flight briefing is all about?
28th Jun 2012, 09:01
You might have to rest worried then... Too many special requirements... If you give me 2, 3 days to prepare every city pair, maybe. Different noise abatement, do I have to say squawk on first contact or not, if cleared direct on a STAR you still have to comply with ALT restrictions abeam a no-more valid waypoint (in OZ you do!), almost every AP has got different Radio fail proc, do I call 10 before ready for push, or when ready, what do I have to tell them.... And that is not even taken into account every operational special ops, like fueling with pax on board, de-icing, you name it.
It's not unsafe, but impossible to cope with every local specialty...
But the topic is a different one. What is the ICAO standard with regards to speed assignment after approach clearance received.
28th Jun 2012, 09:36
I hear what you are saying what-goes-up. But you also highlight a problem. I don't know if there is an ICAO standard but don't forget that every region and country can publish differences with ICAO standards so knowing the ICAO standard may not help. There are as many variances from standards as there are standards.
28th Jun 2012, 09:46
WetFeet, I agree. Every authority can issue as many variances as they wish... All I am saying is, we can not cope with knowing all of them. So what would that say...??
No pun against your statement at all!
And as for my initial question... I know it is an academic one but still a base for a good discussion... :)
28th Jun 2012, 20:42
Isnt the aircraft still bound by their respective CAT speed? There are also frequently speed restrictions on the missed...
With RNP procedures, between optimizing TOD, and making sure the ac fits in the queue with non-RNP, I usually set waypoints with speed restrictions to fix the ac at target altitudes...
With reduced separation on approach, it seems this needs to be sorted out...good question.
29th Jun 2012, 08:36
<<With reduced separation on approach, it seems this needs to be sorted out...good question.>>
If tight spacing is employed it must be radar controlled. In such situations you fly the speeds given by the radar controller. If you are unable to accept them you must give warning in advance of final approach. I worked as a Heathrow Radar controller for 31 years and I could count on one hand the number of times a pilot told me he couldn't fly the speed I had given, usually due a weight problem.
29th Jun 2012, 17:23
Watching Heathrow aircraft approach queues, they do an amazing job, its nerve wracking just to watch, let alone what it takes to keep everyone lined up.
Some of the recat models, and matrix models use a combination of radar sep and nm for the heavies, especially with pair-wise models. One of these days, they will get ATC involved in some of the crazy scenarios they have dreamed up, ie 64x64 matrix?!?!
29th Jun 2012, 17:42
<<let alone what it takes to keep everyone lined up.>>
29th Jun 2012, 17:54
Isnt the aircraft still bound by their respective CAT speed?
Interesting question again. Lets check the 737.
The airplane is classified as a Medium Type Category.
The airplane is certified as Approach Category "C".
Thats what out manual says, however for the -800 Vref for flaps 30 is quite often higher than 140kts, even flaps 40 can be close to or over 140kts. It is still category C...
30th Jun 2012, 06:03
Eurocontrol have found it necessary to issue the following with regards to speed control vs range to touchdown.
SKYbrary - Unstabilised Approach: Inappropriate ATC Speed Instructions (http://www.skybrary.aero/index.php/Unstabilised_Approach:_Inappropriate_ATC_Speed_Instructions)
That must mean that, ATCOs not understanding basic aircraft performance, is a common and danger triggering fact.
The problem could be that the ATC-SIM will accept almost any speeds given at any point. I have seen trainees use complete rubbish speeds fresh out of the college.
30th Jun 2012, 08:33
That link won't open for me. However, when I had trainees on Tower, Approach and Approach Radar it was an integral part of their training that they gained an appreciation of the performance characteristics of the types of aircraft they were likely to encounter. It was the same with all OJTI's I worked with, as well as when I was a trainee myself all those years ago. If they didn't have that appreciation, they didn't validate.
30th Jun 2012, 10:59
Canada ATC Manual of Operations:
554.8 Advise an aircraft to resume normal speed when application of a speed adjustment is no longer necessary, except when the aircraft has been cleared for an approach (N)
(N) Note 2:
An approach clearance supersedes a speed adjustment request, and aircraft are expected to make their own speed adjustments to complete the approach. If you require aircraft to adjust speed while on approach, restate the request.