Landing Clearance
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Landing Clearance
A question for ATC and Pilots.
Is there a clear rule stating for both ATC and Pilots what is the minimum distance from the threshold of a runway an aircraft shall proceed without having received an explicit landing clearance?
Ant inputs will be helpful. Thanks
Is there a clear rule stating for both ATC and Pilots what is the minimum distance from the threshold of a runway an aircraft shall proceed without having received an explicit landing clearance?
Ant inputs will be helpful. Thanks
Avoid imitations
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I don't think there is a general rule on minimum distance but company SOPs may dictate a minimum altitude above the threshold.
Flying ants don't usually ask for landing clearance. ((
)) 
Ant inputs will be helpful. Thanks
))
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I wanted to write 'Any" instead of "ant". Finger or keyboard malfunction.I know this a subject with great controversy. I have looked from the ICAO Doc4444 to the 8168, the 9426 and 9689 etc. I have visited Skybrary and Forums. I have discussed it with pilots and controllers. So far, I have just a big lot of different answers and opinions. Looking at Forums, there are discussion for years about it. Amazing. Hasn't someoone felt the need to implement a stupid rule. I couldn't find the meaning of a "late landing clearance" neither. It is just made up. I'll keep trying.
Thank you for all inputs and references if you know of any by any chance.
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If a pilot has been told to "expect late landing clearance (reason)", in my experience, the crew will decide the "go around" point/level taking into account the prevailing situation, vis, w/v and the reason landing permission has been withheld.
A modern aircraft may execute a go around from 50 odd feet or less and not touch the runway. So a controller may give a go around just short of the threshold (if that is a safe option in relation to the obstruction)...however, consider the pilot's "reaction time" and aircraft's inertia!
A modern aircraft may execute a go around from 50 odd feet or less and not touch the runway. So a controller may give a go around just short of the threshold (if that is a safe option in relation to the obstruction)...however, consider the pilot's "reaction time" and aircraft's inertia!
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re "Late landing clearance"
In times gone by, the Outer marker or approx 4nm on finals was the distance by which ATC would NORMALLY AIM to issue a landing clearance.
However, with tighter spacing together with reduced runway separation rules, that is history, so a "late landing" clearance may be defined as when the the aircraft has or will pass the point at which clearance to land would normally be given.
In times gone by, the Outer marker or approx 4nm on finals was the distance by which ATC would NORMALLY AIM to issue a landing clearance.
However, with tighter spacing together with reduced runway separation rules, that is history, so a "late landing" clearance may be defined as when the the aircraft has or will pass the point at which clearance to land would normally be given.
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Haven't you ever heard
"Keep it coming, keep it coming, the sur-face-winddd-iiiis-twoo-sevennn-zeroww-degrees-one-zeroww-knots, Cleeeeeeeeeeeeeeeaaaar toland"
(instant squeak of tyres…followed by...)
"Thanks for that, Ground one two one nine"
"well done, point nine, chs"
?
"Keep it coming, keep it coming, the sur-face-winddd-iiiis-twoo-sevennn-zeroww-degrees-one-zeroww-knots, Cleeeeeeeeeeeeeeeaaaar toland"
(instant squeak of tyres…followed by...)
"Thanks for that, Ground one two one nine"
"well done, point nine, chs"
?
....Done it loads of times
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Essentially, there's no specific range that a controller must give a clearance by, unless set by a local procedure. If a controller is unable to issue a clearance, a pilot will continue the approach for as long as they are happy to do so, and then go-around if they don't have a clearance. If they get a clearance before that point, they land.
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Tower ATC
Nothing stated as far as I know. We have a general rule at the airport I work at (single runway) that landing clearance is given by 2nm (due to a number of factors). Any time that this is reduced we "should" inform the pilot to expect a late landing clearance (with reason).
During Low Visibility Operations this is increased to 3nm to allow for increased risk of go-arounds - where separation between the preceding departure and the aircraft on a potential missed approach may be an issue (because there is no chance of applying Reduced Separation in the Vicinity of an Aerodrome in these circumstances). This at least provides 3nm + a certain amount of runway between the 2 aircraft should the approach be aborted (albeit you should also consider the speed of the aircraft involved - Vr vs. Vapp).
I guess it depends on what Radar separation needs to be applied...if you require 3 nm between aircraft the above is ok, if you require the standard 5nm then you'd need to apply larger spacing on final approach.
During Low Visibility Operations this is increased to 3nm to allow for increased risk of go-arounds - where separation between the preceding departure and the aircraft on a potential missed approach may be an issue (because there is no chance of applying Reduced Separation in the Vicinity of an Aerodrome in these circumstances). This at least provides 3nm + a certain amount of runway between the 2 aircraft should the approach be aborted (albeit you should also consider the speed of the aircraft involved - Vr vs. Vapp).
I guess it depends on what Radar separation needs to be applied...if you require 3 nm between aircraft the above is ok, if you require the standard 5nm then you'd need to apply larger spacing on final approach.
Last edited by good egg; 22nd Nov 2014 at 22:26. Reason: 3nm/5nm radar separation
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I've gotten landing clearance in the flare.
and yes, we asked and then demanded landing clearance
it is possible for atc to make a mistake
it is possible for pilots to make a mistake
we also have a reminder in our plane and we put a checklist somewhere special when we have landing clearance etc
and yes, we asked and then demanded landing clearance
it is possible for atc to make a mistake
it is possible for pilots to make a mistake
we also have a reminder in our plane and we put a checklist somewhere special when we have landing clearance etc
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Thank you all for your replies.
It certainly varies from airport to airport, operators to operator and based on several factors (wx, a/c categories involved, etc). I understand that everyone is quite happy with it and it has been working without significant issues. Being a "safety" guy, I am looking on how we can improve such a lack in the rules or at least have a little more guidance.
What ICAO says is that the landing clearance is based on "reasonable assurance" that the runway is clear when an arriving aircraft crosses the threshold. It says also that if under radar control, the landing clearance shall be issued not later than 2 miles. Makes sense to me as the minimum separation would be 2.5NM (based in certain conditions - RWY occupancy time, Xwind, etc).
Just a big headache trying to do a torough analysis of this particular occurrence. Your inputs are helping.
Thank you.
It certainly varies from airport to airport, operators to operator and based on several factors (wx, a/c categories involved, etc). I understand that everyone is quite happy with it and it has been working without significant issues. Being a "safety" guy, I am looking on how we can improve such a lack in the rules or at least have a little more guidance.
What ICAO says is that the landing clearance is based on "reasonable assurance" that the runway is clear when an arriving aircraft crosses the threshold. It says also that if under radar control, the landing clearance shall be issued not later than 2 miles. Makes sense to me as the minimum separation would be 2.5NM (based in certain conditions - RWY occupancy time, Xwind, etc).
Just a big headache trying to do a torough analysis of this particular occurrence. Your inputs are helping.
Thank you.
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Where I work they aim to give it by 4nm, but will tell us late landing clearance if under 2nm. As far as rules for how far to go without it, I am not aware of any unless operator imposed. In the light twin I used to fly we would fly level along the runway until we got it if it was suitable to do so (ie. vehicle vacating at the far end), flying something heavier now there is no rule but I wouldn't really want to continue past 50' at the latest unless I was 100% sure of getting it, and in reality depending on the circumstance would call a go around earlier than that anyway.
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There is a range of different interpretations of the ICAO standards on this topic. To give two examples, in the US a clearance to land may be issued while there is one or more aircraft sill in the air on the approach ahead of the aircraft that gets the clearance - this meets the rules if, as you point out, there is a reasonable assurance that the runway will be clear when the aircraft gets there. On the other hand, in the UK, where I did most of my controlling, the rules are that landing clearance cannot get issued until the previous lander has vacated or the previous departure is airborne (I think it used to say not before a departing aircraft has crossed the upwind end of the runway).
Personally, I prefer the UK way but that may well be because that was what I was brought up with. But it does mean that landing clearance sometimes isn't issued until the wheels of the lander are floating over the runway (although the UK book does say that the aircraft should not be allowed to cross the beginning of the runway until the clearance can be issued - I think this is one of the most commonly flouted rules) whereas, in the US, a clearance to land could have been issued some miles earlier. There are strengths and weaknesses in both systems.
Certainly from my experience, when things were going to be 'tight', as the controller I made sure that everyone involved knew what was happening and knew what to do if the plan didn't work - as waxo says, everyone must be on the same page.
To answer the original question, there is no absolute minimum distance by which a landing clearance must be issued although individual aircraft operators' SOPs or ATC unit procedures may specify something. For example, during LVOs there is almost always a minimum distance by which the clearance is issued because the need to protect the ILS signal by a specific range means that the runway will then be available.
There are many, many variables that affect when a clearance can be issued and to try to write procedures to cover every situation is probably not going to work and would undoubtedly result in less flexibility, and more go-arounds or lower capacity. What might be better in my view would be to ensure that the controllers know their jobs and are able to apply professional judgement to any situation.....but I am now getting very old and I recognise such ideas do not fit with modern ATC.
Overall, although there are many discussions on the topic, often starting when someone is exposed to a different way of operating to that with which they are used, it's something that appears to be quite quickly understood and, ultimately, which works in most situations regardless of the rules being applied.
Finally, I would advise caution about making assumptions about why the rules are written as they are - the 2 mile range mentioned for radar approaches was, I think, put there for other reasons than you surmise.
Personally, I prefer the UK way but that may well be because that was what I was brought up with. But it does mean that landing clearance sometimes isn't issued until the wheels of the lander are floating over the runway (although the UK book does say that the aircraft should not be allowed to cross the beginning of the runway until the clearance can be issued - I think this is one of the most commonly flouted rules) whereas, in the US, a clearance to land could have been issued some miles earlier. There are strengths and weaknesses in both systems.
Certainly from my experience, when things were going to be 'tight', as the controller I made sure that everyone involved knew what was happening and knew what to do if the plan didn't work - as waxo says, everyone must be on the same page.
To answer the original question, there is no absolute minimum distance by which a landing clearance must be issued although individual aircraft operators' SOPs or ATC unit procedures may specify something. For example, during LVOs there is almost always a minimum distance by which the clearance is issued because the need to protect the ILS signal by a specific range means that the runway will then be available.
There are many, many variables that affect when a clearance can be issued and to try to write procedures to cover every situation is probably not going to work and would undoubtedly result in less flexibility, and more go-arounds or lower capacity. What might be better in my view would be to ensure that the controllers know their jobs and are able to apply professional judgement to any situation.....but I am now getting very old and I recognise such ideas do not fit with modern ATC.
Overall, although there are many discussions on the topic, often starting when someone is exposed to a different way of operating to that with which they are used, it's something that appears to be quite quickly understood and, ultimately, which works in most situations regardless of the rules being applied.
Finally, I would advise caution about making assumptions about why the rules are written as they are - the 2 mile range mentioned for radar approaches was, I think, put there for other reasons than you surmise.
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Australia's Manual of Air Traffic Services states that a landing clearance must be issued before the aircraft reaches 200ft AGL. Many jet RPT aircraft would have gone around by then and many single or twin GA aircraft will land even if they don't get a clearance. 
Heard on the radio yesterday at a busy airport with a mix of GA and airline traffic
Twr: ABC cleared to land runway XX
ABC: (said in a diffident and uncertain low voice) Ummmm could I take off first, ABC ?
Twr: ABC cleared to land runway XX
ABC: (said in a diffident and uncertain low voice) Ummmm could I take off first, ABC ?
All boils down to the fact if you ask (say) 10 controllers a question, you'll get 20 different answers.
Landing at Heathrow in a Brymon Herald (yes it was many years ago) we could hear a Trident catching us up. He reported OM well before we touched down and we had delayed landing clearance due to the 'Link' helicopter crossing ahead. The controller (possibly talkdownman?) kept telling the Trident 'continue' and just as we started to exit the runway the Trident said 'I'm on the deck' to which the controller replied 'cleared to land'!!
Landing at Heathrow in a Brymon Herald (yes it was many years ago) we could hear a Trident catching us up. He reported OM well before we touched down and we had delayed landing clearance due to the 'Link' helicopter crossing ahead. The controller (possibly talkdownman?) kept telling the Trident 'continue' and just as we started to exit the runway the Trident said 'I'm on the deck' to which the controller replied 'cleared to land'!!
The breakdown of separation occurs when the aircraft crosses the threshold to land. I would go around just prior to crossing the threshold if I hadn't received a clearance.
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At my TWR, in the small local airport, I often give landing clearance when pilots report "inbound on final"(about 12 DME), the rest of working from then belongs to him, my working just observe RWY and preparing for "go around" clearance in any abnormal situation; why we have to wait until he is too near the RWY? Infact pilots always request landing clearance on short final if I have not given him yet on long final. My work is non radar app, using VOR/DME.