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IFlyVeryLittle
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Cleared to land

Tue Jun 01, 2021 4:00 pm

Beyond the obvious, what exactly has to happen for a controller to deliver those words to an air-crew approaching an airport. What conditions have to exist in the immediate air vicinity and on the ground to cross that "cleared to land" threshold, and can that clearance be revoked should those conditions change? Thanks.
 
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BWIAirport
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Re: Cleared to land

Tue Jun 01, 2021 4:06 pm

This is more of a follow-up than it is an answer since I do not have expertise on the subject, but listening to LiveATC feeds I'll usually hear landing clearance granted right after arrival aircraft contact the tower on approach. "Baltimore Tower, Southwest 2529 10 mile final ILS runway 33L" "Southwest 2529, traffic will depart runway 28, winds 300 at 8, runway 33L cleared to land." So clearance is given even if there is an intersecting departure or if there's another arrival on short final.
Given that clearance is often given even if traffic is currently in the way, what circumstances would lead a controller to say "continue approach" rather than give landing clearance?
 
IAHFLYR
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Re: Cleared to land

Tue Jun 01, 2021 5:04 pm

You may find some of this helpful and other parts not so much, but this is what the rules are for controllers working local control.

https://www.faa.gov/air_traffic/publica ... on_10.html
 
VSMUT
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Re: Cleared to land

Tue Jun 01, 2021 5:19 pm

The runway has to be clear of aircraft and vehicles, and the aircraft must be first in line to land. On top of being a permission to land, it effectively tells the pilot that everything is clear.

Unless you are in the US, in which case several aircraft can be cleared to land at the same time.
 
chimborazo
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Re: Cleared to land

Tue Jun 01, 2021 7:55 pm

VSMUT wrote:
The runway has to be clear of aircraft and vehicles, and the aircraft must be first in line to land. On top of being a permission to land, it effectively tells the pilot that everything is clear.

Unless you are in the US, in which case several aircraft can be cleared to land at the same time.


Which I’ve always found a bit strange about the US system. Clearly it works with thousands of movements every day but I can’t see how it enhances safety to have a number of aircraft cleared to land in sequence. It just seems like an unnecessary hole in the Swiss cheese... it relies on the controller being able to contact the flight crew to tell them to go around if the situation becomes unsafe, perhaps with a problem with the aircraft in front. If they get blocked or somehow can’t then contact the aircraft to instruct a go around, it just seems less safe than a positive cleared to land without anyone in front being a factor (of course even in the last situation there could still be a runway incursion or similar).

Does anyone know a case of an aircraft being told to go around because of an incident with an aircraft ahead but then not responding? There’s the famous Air Canada incident at SFO... not sure if that caused a risk with another aircraft ahead though.

Of course, the pilots themselves can make a determination to go around if they see something amiss, but what if the controller knows something they don’t and isn’t able to contact them?

Finally, does it really help that much with sequencing to have multiple aircraft cleared to land? Flip side on that is I’ve seen a lot of on-board vids from Heathrow where an aircraft is getting very close to minimums before getting landing clearance.
 
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BWIAirport
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Re: Cleared to land

Tue Jun 01, 2021 8:38 pm

I think in the US it relieves the duty of the controller a little bit to just clear the arrival for landing right away. That way the controller doesn't have an additional phrase they need to say during busy times. Landing clearance is inevitable (like takeoff clearance) but also requires some forecasting (unlike takeoff clearance, which is immediate). So the idea is "yes, we don't see any circumstances that will preclude you from safely landing when you get to the runway in ten miles, so we'll clear you awhile."
They can always issue a go-around.
 
atcdan
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Re: Cleared to land

Wed Jun 02, 2021 12:54 am

To chime in, as a controller in the US it means there exists a reasonable assurance that the runway will be clear when your aircraft crosses the landing threshold.

The only times I would not issue a landing clearance is if I will be allowing a vehicle on the runway, have an aircraft taxiing on the runway, or I plan to change you to a different parallel runway. Also, if you’re overtaking traffic ahead and the spacing it tight I may withhold landing clearance until I am assured by the respective speeds that the runway will be clear.

In most countries, the use of “anticipated separation” is not allowed.
 
IAHFLYR
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Re: Cleared to land

Wed Jun 02, 2021 1:36 pm

atcdan wrote:
To chime in, as a controller in the US it means there exists a reasonable assurance that the runway will be clear when your aircraft crosses the landing threshold.

The only times I would not issue a landing clearance is if I will be allowing a vehicle on the runway, have an aircraft taxiing on the runway, or I plan to change you to a different parallel runway. Also, if you’re overtaking traffic ahead and the spacing it tight I may withhold landing clearance until I am assured by the respective speeds that the runway will be clear.

In most countries, the use of “anticipated separation” is not allowed.


To echo what atcdan wrote, anticipated separation in the U.S. certainly cuts down on radio transmissions particularly in a critical phase of flight when as a former tower controller I'd rather not be issuing a landing clearance as they approach the threshold. Just my opinion and it clearly works numerous time a day, not that withholding the landing clearance until the arrival is the next to land does not work as it is proven to work as well.
 
trent768
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Re: Cleared to land

Wed Jun 02, 2021 5:04 pm

On a related note, how low can an aircraft continue their approach until a landing clearance is given?

I don't remember the title, but I saw a youtube video where an aircraft on final was given the expect late landing clearance notice at LHR. It was last second indeed, since the GPWS yelled "minimum!" literally after the pilot finished the "cleared to land" read back.
 
IAHFLYR
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Re: Cleared to land

Wed Jun 02, 2021 5:15 pm

trent768 wrote:
On a related note, how low can an aircraft continue their approach until a landing clearance is given?

I don't remember the title, but I saw a youtube video where an aircraft on final was given the expect late landing clearance notice at LHR. It was last second indeed, since the GPWS yelled "minimum!" literally after the pilot finished the "cleared to land" read back.


In the U.S. they technically they have to be issued the landing clearance before crossing the threshold, though at that time the readback if you got one from the crew would have them very very close to touching down.
 
GalaxyFlyer
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Re: Cleared to land

Wed Jun 02, 2021 8:24 pm

I waiting for departure at KJFK one busy afternoon. L1011 with the old “continue” instruction, as spacing was close and it was Kennedy. Traffic ahead missed the exit, 1011 was given the “go around” after the threshold, probably at 50’ or 60’, just made with touching down. The captain complained, of course, he was complicit.
 
VSMUT
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Re: Cleared to land

Wed Jun 02, 2021 8:58 pm

trent768 wrote:
On a related note, how low can an aircraft continue their approach until a landing clearance is given?


I've received it in an extended flare at less than 10 ft.
 
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Starlionblue
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Re: Cleared to land

Wed Jun 02, 2021 11:19 pm

trent768 wrote:
On a related note, how low can an aircraft continue their approach until a landing clearance is given?

I don't remember the title, but I saw a youtube video where an aircraft on final was given the expect late landing clearance notice at LHR. It was last second indeed, since the GPWS yelled "minimum!" literally after the pilot finished the "cleared to land" read back.


On a typical ILS approach, minimum is 200 feet AAL. That's still about 15 seconds from touchdown.

If the visibility was good and you could thus see the runway is clear, there's no problem continuing for a few more seconds as clearance should be forthcoming soon.

If you don't get a clearance, at some point you have to go around of course. Sometime before 50 feet AAL can be a good rule of thumb, as that is the nominal threshold height.
 
FlyHossD
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Re: Cleared to land

Thu Jun 03, 2021 11:49 pm

chimborazo wrote:
Does anyone know a case of an aircraft being told to go around because of an incident with an aircraft ahead but then not responding? There’s the famous Air Canada incident at SFO... not sure if that caused a risk with another aircraft ahead though.


Once had to go-around because of the aircraft behind us!

On final to STL and cleared to land by STL Tower on 30R, we were then directed to go-around as a WN flight was rapidly overtaking us from behind and was not answering STL Tower. Apparently, they were not on the Tower frequency.

So, go-around we did and got a quick return and landed 30R after all. When we asked for the WN flight number, we were told, "Don't worry, we'll take care of it." But we pressed for the answer so we could include it in our report to the company.
 
chimborazo
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Re: Cleared to land

Fri Jun 04, 2021 10:04 am

FlyHossD wrote:
chimborazo wrote:
Does anyone know a case of an aircraft being told to go around because of an incident with an aircraft ahead but then not responding? There’s the famous Air Canada incident at SFO... not sure if that caused a risk with another aircraft ahead though.


Once had to go-around because of the aircraft behind us!

On final to STL and cleared to land by STL Tower on 30R, we were then directed to go-around as a WN flight was rapidly overtaking us from behind and was not answering STL Tower. Apparently, they were not on the Tower frequency.

So, go-around we did and got a quick return and landed 30R after all. When we asked for the WN flight number, we were told, "Don't worry, we'll take care of it." But we pressed for the answer so we could include it in our report to the company.


Ha! And I thought WN were only fast on the taxi ways :-)

BA 747 angry pilot after the controller instructed them to go around because they were too slow for traffic behind them... that had a big conversation about it. Love listening to a well-spoken angry Brit trying to keep a lid on it!
 
gloom
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Re: Cleared to land

Fri Jun 04, 2021 10:34 am

IAHFLYR wrote:
To echo what atcdan wrote, anticipated separation in the U.S. certainly cuts down on radio transmissions particularly in a critical phase of flight when as a former tower controller I'd rather not be issuing a landing clearance as they approach the threshold. Just my opinion and it clearly works numerous time a day, not that withholding the landing clearance until the arrival is the next to land does not work as it is proven to work as well.


It's not like it's a problem in my part of the world, anyways (EU).

Arriving traffic is maxed at 4-5 planes per runway. You need to be stabilized (usually on loc, local procedures depending) to be transferred to TWR freq. So, assuming 2 parallel rwys, and departures (who join only when ready for dep, and act on freq as no1), it's not that much traffic anyways. A few planes, and a few transmissions. Both GND and APP, they're much more busy freqs, but TWR? Rarely, maybe with some more VFR traffic, but in large airports it's quite rare sight to see.

Cheers, Adam
 
IAHFLYR
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Re: Cleared to land

Fri Jun 04, 2021 2:03 pm

gloom wrote:
It's not like it's a problem in my part of the world, anyways (EU).


Exactly, thus the last few words of my post. Simply different type of operation and they both work.

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