250 kts/FL100 - Help!
Thread Starter
Join Date: Oct 2000
Location: Manchester, UK
Posts: 43
Likes: 0
Received 0 Likes
on
0 Posts
250 kts/FL100 - Help!
Guy’s,
Was hoping that someone might be able to put me out of my misery with respect to the FL100, 250kts speed limit issue. I personally think the issue is universally misunderstood by many flight crew, the confusion amplified by modern FMS systems which introduce an arbitrary 250kt speed limits into the a/c guidance @ FL100/10000’
I’ll limit my discussion to the UK to keep things simple. The ANO roughly states the following:
The 250kts speed limit does not apply to:
Flights in Class A and B airspace
IFR flights in Class C airspace (currently no class C in UK)
IFR flights in Class D airspace when authorised by an ATC unit
Test flights in accordance with specified conditions
Aircraft taking part in flying displays when authorised by the CAA
Aircraft subject to written permission granted by the CAA
Aircraft not subject to the ANO
It is quite interesting (or perhaps not!) that the ANO is quite specific with regards to class D airspace, in that it infers that ATC have the authority to set the law, as it were, with respect to speed limits. Elsewhere, except for the above cases, we have to assume that the standard 250kts limit stands below FL100.
This has resulted in, in my opinion, some ambiguous situations developing. To set a brief scene, my home airfield lies under the Daventry CTA (class A, base level 45) and below this, the aerodrome CTR begins (Class D). Commonly, on arrival under radar vectors, approaching FL100, crews will query “any speed control” to which ATC will usually respond “no ATC speed”. This has lead to me wonder on many occasions – is the controller advising that there will be no speed limit on entering the class D zone, or does (s)he mean that no specific speed is required to enable him/her to expeditiously/safely control the traffic flow (as there in no legal speed limit at FL100 on this routing)
Further to this, is my understanding correct in that a controller has no authority to authorise speed above the limit should he vector us through, say, class E airspace or outside of controlled airspace.
Finally, the grey area of departures. Most published departure plates have a speed limit stated of “250kts or less below FL100”. Is it to be assumed that this is an automatically issues ATC speed limit, as the class of airspace the departure utilises may not warrant such a speed limit. Is there any difference if you are placed under radar vector as opposed to continuing with the published departure?
I genuinely believe many of these issues are not understood fully amongst the flight deck fraternity! For those of you who (like myself) don’t have anything better do on Good Friday, it might provoke some discussion
Regards,
Cuban_8.
Was hoping that someone might be able to put me out of my misery with respect to the FL100, 250kts speed limit issue. I personally think the issue is universally misunderstood by many flight crew, the confusion amplified by modern FMS systems which introduce an arbitrary 250kt speed limits into the a/c guidance @ FL100/10000’
I’ll limit my discussion to the UK to keep things simple. The ANO roughly states the following:
The 250kts speed limit does not apply to:
Flights in Class A and B airspace
IFR flights in Class C airspace (currently no class C in UK)
IFR flights in Class D airspace when authorised by an ATC unit
Test flights in accordance with specified conditions
Aircraft taking part in flying displays when authorised by the CAA
Aircraft subject to written permission granted by the CAA
Aircraft not subject to the ANO
It is quite interesting (or perhaps not!) that the ANO is quite specific with regards to class D airspace, in that it infers that ATC have the authority to set the law, as it were, with respect to speed limits. Elsewhere, except for the above cases, we have to assume that the standard 250kts limit stands below FL100.
This has resulted in, in my opinion, some ambiguous situations developing. To set a brief scene, my home airfield lies under the Daventry CTA (class A, base level 45) and below this, the aerodrome CTR begins (Class D). Commonly, on arrival under radar vectors, approaching FL100, crews will query “any speed control” to which ATC will usually respond “no ATC speed”. This has lead to me wonder on many occasions – is the controller advising that there will be no speed limit on entering the class D zone, or does (s)he mean that no specific speed is required to enable him/her to expeditiously/safely control the traffic flow (as there in no legal speed limit at FL100 on this routing)
Further to this, is my understanding correct in that a controller has no authority to authorise speed above the limit should he vector us through, say, class E airspace or outside of controlled airspace.
Finally, the grey area of departures. Most published departure plates have a speed limit stated of “250kts or less below FL100”. Is it to be assumed that this is an automatically issues ATC speed limit, as the class of airspace the departure utilises may not warrant such a speed limit. Is there any difference if you are placed under radar vector as opposed to continuing with the published departure?
I genuinely believe many of these issues are not understood fully amongst the flight deck fraternity! For those of you who (like myself) don’t have anything better do on Good Friday, it might provoke some discussion
Regards,
Cuban_8.
Join Date: Dec 2003
Location: somewhere out there
Posts: 121
Likes: 0
Received 0 Likes
on
0 Posts
Hi Cuban, to try and answer your questions:
The standard speed limit below FL100 is 250 kts, except in the specific circumstances you have stated which are also specified in our Manual of Air Traffic Services Part 1 (MATS pt1) which is essentialy the ATC bible.
Transiting from class A to Class D - if ATC say no ATC speed restriction then there is NO speed restriction, you can basically fly at whatever speed you deem necessary, we as "guardians " of that KNOWN TRAFFIC environment can de-restrict your speed.
Class E airspace whilst controlled airspace is NOT A KNOWN TRAFFIC ENVIRONMENT as VFR flights can happily transit through that area of CONTROLLED airspace without speaking to an ATC unit, therefore the SEE AND AVOID principle applies, hence the requirement for 250kts. However if you are flying through class E airspace and ATC say No Speed Restriction, then the 250 below 100 STILL APPLIES.
As for departures, the 250 below 100 is published purely for separation standards against traffic departing ahead of you. This is based on a departure table that tower controllers use, for us at EGPF it is designed to provide 5 miles constant or increasing separation between successive departures when 30 miles from the airfield following the SID route. If you are told no speed then the separation will be provided by other means, either there is no traffic likely to conflict, or your aircraft performance is such that no speed restriction will result in vertical separation from any conflicting traffic well before the 30 miles.
I heartily agree that this issues are not understood by many aircrew, as a controller working with Class E airspace, I am often amazed at pilots lack of appreciation of the rules and I'm sure that the majority don't even realise that they are in fact in class E airspace and just assume that a Radar Control Service means that we know about everything that is flying around. Unfortunately that isn't the case.
Thankfully posts like yours are promoting discussion amongst aircrew who are then taking the time to go and visit the ATC units concerned and have that cup of coffee and the chocolate biscuits that are always available for our visitors.
I've been lucky enough in my career to have spent many happy hours on the flight deck of aircraft and discuss the problems that we as ATCO's have and your requirements as pilots. This mutual appreciation of each others difficulties has helped me no end and I'm glad that slowly but surely controllers are being welcomed back on to the flight deck and more and more aircrew are taking the time to visit ATC units.
Only through mutual understanding of each others problems and needs can we make the skies a safer and happier place to be.
The standard speed limit below FL100 is 250 kts, except in the specific circumstances you have stated which are also specified in our Manual of Air Traffic Services Part 1 (MATS pt1) which is essentialy the ATC bible.
Transiting from class A to Class D - if ATC say no ATC speed restriction then there is NO speed restriction, you can basically fly at whatever speed you deem necessary, we as "guardians " of that KNOWN TRAFFIC environment can de-restrict your speed.
Class E airspace whilst controlled airspace is NOT A KNOWN TRAFFIC ENVIRONMENT as VFR flights can happily transit through that area of CONTROLLED airspace without speaking to an ATC unit, therefore the SEE AND AVOID principle applies, hence the requirement for 250kts. However if you are flying through class E airspace and ATC say No Speed Restriction, then the 250 below 100 STILL APPLIES.
As for departures, the 250 below 100 is published purely for separation standards against traffic departing ahead of you. This is based on a departure table that tower controllers use, for us at EGPF it is designed to provide 5 miles constant or increasing separation between successive departures when 30 miles from the airfield following the SID route. If you are told no speed then the separation will be provided by other means, either there is no traffic likely to conflict, or your aircraft performance is such that no speed restriction will result in vertical separation from any conflicting traffic well before the 30 miles.
I heartily agree that this issues are not understood by many aircrew, as a controller working with Class E airspace, I am often amazed at pilots lack of appreciation of the rules and I'm sure that the majority don't even realise that they are in fact in class E airspace and just assume that a Radar Control Service means that we know about everything that is flying around. Unfortunately that isn't the case.
Thankfully posts like yours are promoting discussion amongst aircrew who are then taking the time to go and visit the ATC units concerned and have that cup of coffee and the chocolate biscuits that are always available for our visitors.
I've been lucky enough in my career to have spent many happy hours on the flight deck of aircraft and discuss the problems that we as ATCO's have and your requirements as pilots. This mutual appreciation of each others difficulties has helped me no end and I'm glad that slowly but surely controllers are being welcomed back on to the flight deck and more and more aircrew are taking the time to visit ATC units.
Only through mutual understanding of each others problems and needs can we make the skies a safer and happier place to be.
Thread Starter
Join Date: Oct 2000
Location: Manchester, UK
Posts: 43
Likes: 0
Received 0 Likes
on
0 Posts
caniplaywithmadness,
Thanks for that - much appreciated!
Think the problem is not entirely due the flight deck ignorance. It is in fact very hard to distinguish the various classes of airspace from the enroute charts that we have (no doubt you've seen them). They're nothing like the clear VFR jobbies that the CAA produce! There is no excuse for not knowing your own airfields details, but when flying downroute to unfamiliar airfields it can be frustrating. Especially when confidence in ATC is not what it is here!!
Will have to go and sample my ATC's chocolate biscuits again soon!
Regards,
Cuban_8
Thanks for that - much appreciated!
Think the problem is not entirely due the flight deck ignorance. It is in fact very hard to distinguish the various classes of airspace from the enroute charts that we have (no doubt you've seen them). They're nothing like the clear VFR jobbies that the CAA produce! There is no excuse for not knowing your own airfields details, but when flying downroute to unfamiliar airfields it can be frustrating. Especially when confidence in ATC is not what it is here!!
Will have to go and sample my ATC's chocolate biscuits again soon!
Regards,
Cuban_8
However if you are flying through class E airspace and ATC say No Speed Restriction, then the 250 below 100 STILL APPLIES.
And in fact I think you need to take care of this for the pilots within controlled airspace. The construction of CTRs/CTAs is often quite complex, and it's almost impossible when being vectored off a planned route to keep track of the airspace class the aircraft is passing through.
I'm not suggesting that this is an excuse for the pilots not knowing the rules.
Now all I want is an aircraft that does more than 250 kt.
Join Date: Aug 2002
Location: Southampton
Posts: 97
Likes: 0
Received 0 Likes
on
0 Posts
Transiting from class A to Class D - if ATC say no ATC speed restriction then there is NO speed restriction, you can basically fly at whatever speed you deem necessary, we as "guardians " of that KNOWN TRAFFIC environment can de-restrict your speed.
In Cuban8's example:
To set a brief scene, my home airfield lies under the Daventry CTA (class A, base level 45) and below this, the aerodrome CTR begins (Class D). Commonly, on arrival under radar vectors, approaching FL100, crews will query “any speed control” to which ATC will usually respond “no ATC speed”.
If this is not the "assumed" case then in all such circumstances perhaps we must increase our already congested RT frequencies with such responses as;
Pilot: "passing FL110, any speed restriction?"
ATC: "No speed restriction with me, until you are passing FL65 where you will be leaving CAS and standard speed limits will apply, or if I transfer you to xxx who may not be able to authorise high speed"
Join Date: Jun 2001
Location: southampton,hampshire,england
Posts: 869
Likes: 0
Received 0 Likes
on
0 Posts
Too Much Crap!
Controllers already have far too much to say as a result of "drip-drip-drip" amendments over the years; each transmission is like a lawyer-friendly exclusion clause with only limited executive or useful function. What say we turn over a new leaf and assume the pilots can read? I miss out all the crap and the traffic still seems to get to the right place at the right level. As for the speed restriction, isn't it ludicrous that an aircraft painted one colour has to comply whereas an aircraft painted a different colour is exempt?......just as a Spitfire, Hawk, Harrier can fly over London on "one" but your brand-new spamcan can't.
Join Date: Feb 2004
Location: Wales
Posts: 302
Likes: 0
Received 0 Likes
on
0 Posts
Hey all :o)
With regard to lifting the 250kt speed restriction, should it be included in co-ordination if it is something that is non standard and then being transferred to another sector / unit? There will be a discussion to obtain a level for the inbound how long does it take to say and he will be deristricted - at least it will give the next atco a heads up.
However, in the case of an aircraft changing from Class A, to class E airspace at FL45, are pilots going to be going as hard as >250kts?? theyve gotta slow down for the approach at some time!! If seperation is relying on the speed of the aircraft then I would emphasis the restriction - as mentioned earlier in the thread - its better to cover ure backside ;oP
Turn It off
With regard to lifting the 250kt speed restriction, should it be included in co-ordination if it is something that is non standard and then being transferred to another sector / unit? There will be a discussion to obtain a level for the inbound how long does it take to say and he will be deristricted - at least it will give the next atco a heads up.
However, in the case of an aircraft changing from Class A, to class E airspace at FL45, are pilots going to be going as hard as >250kts?? theyve gotta slow down for the approach at some time!! If seperation is relying on the speed of the aircraft then I would emphasis the restriction - as mentioned earlier in the thread - its better to cover ure backside ;oP
Turn It off
Join Date: Dec 2003
Location: somewhere out there
Posts: 121
Likes: 0
Received 0 Likes
on
0 Posts
The only place I can think of where speed control is continually used to provide separation is within the London TMA and that is simply because of the sheer volume of traffic that flies into and out of the London Airports.
As an approach controller at a reasonably busy airfield I and the majority of my colleagues would prefer to vector rather than apply speed control, when it's not so busy, it makes more sense for us to provide you with vertical / horizontal separation and let you do your own thing with the speed. We tend to find that this works fine in 99% of approach sequences as we have an appreciation of the a/c performance and particular airframe speed limitations at lower levels (E145 as an example), I would only use positive speed control during a sequence of 5 or more successive and closely spaced IFR arrivals.
As for co-ordination, when a/c are handed over to me by Scottish, they are usually above FL100, inbound to the hold, or on a radar heading to separate from other traffic. It is then up to me to decide the position in the sequence of each a/c when they call me and also if it is necessary to apply any speed control.
As an approach controller at a reasonably busy airfield I and the majority of my colleagues would prefer to vector rather than apply speed control, when it's not so busy, it makes more sense for us to provide you with vertical / horizontal separation and let you do your own thing with the speed. We tend to find that this works fine in 99% of approach sequences as we have an appreciation of the a/c performance and particular airframe speed limitations at lower levels (E145 as an example), I would only use positive speed control during a sequence of 5 or more successive and closely spaced IFR arrivals.
As for co-ordination, when a/c are handed over to me by Scottish, they are usually above FL100, inbound to the hold, or on a radar heading to separate from other traffic. It is then up to me to decide the position in the sequence of each a/c when they call me and also if it is necessary to apply any speed control.
