I have noticed on several occasions that a US tower would issue landing clearances to an aircraft although the aircraft ahead is still touching down or has not yet vacated the runway.
I have not experienced that outside of the US and was just reminded of that again in Salzburg when an A320 behind me was told “expect possible late landing clearance”. The landing clearance was issued only after I was safely turned on to the taxiway although had not crossed the double lines.
What is the reason for the difference, in particular what is the use of the US-style landing clearance if it can be withdrawn at any time (i.e. instruction to go around) although that can of course happen at any controlled airport at any time?
I don’t know. But as far as I know, a landing clearance is just like any other clearances. When an aircraft lands, it is prob 99.99 it will vacate at the first taxiway. This takes X seconds from touch down, so it is a straightforward assumption/calculation that the next plane will not collide with the first. It’s also implicit that you cannot land if the runway is occupied in any circumstance, so the end result will always be the same. It’s much better to receive a clearance earlier with a possible late change, than to not receive a clearance until seconds before landing IMO.
It’s also implicit that you cannot land if the runway is occupied in any circumstance
Not in this part of the UK. “Land after” clearances are quite common at our local airport. But sometimes we get “continue approach”, so it’s obviously at the controller’s discretion.
I’d be interested to know from a controller what governs that decision.
LeSving wrote:
It’s also implicit that you cannot land if the runway is occupied in any circumstance
Well, yes you can… ATC can apply reduced separation criteria where an aircraft may land even if the previous landing aircraft is still on the runway or a previous departing aircraft is still on/over the runway provided it is sufficiently far away. There are several conditions involved.
Jacko wrote:
Not in this part of the UK. “Land after” clearances are quite common at our local airport.
Do you mean you can get this while the preceding aircraft is still airborne?
wbardorf wrote:
What is the reason for the difference, in particular what is the use of the US-style landing clearance if it can be withdrawn at any time (i.e. instruction to go around) although that can of course happen at any controlled airport at any time
I’m not sure about European protocol, maybe that is the significant difference (?) but in the US case when the tower says either ‘cleared to land number three’ (etc) or ‘cleared to land’ or nothing at all it has no immediate effect on my operation. At that point I am typically on downwind or base leg and I just keep flying towards a landing with or without a landing clearance. Nothing would change without any landing either clearance until short final. If the initial clearance noted that there are other aircraft landing ahead of me, the impact is that I look for them ahead and avoid flying a short approach.
Where I fly (US), it’s perfectly normal to be get a clearance hat goes for example ‘XYZ cleared to land runway XX, number three behind a Cessna and a Light Sport’, report the Light Sport in sight’. You also get cleared to land when the preceding traffic is still holding short or just taxiing into position. In this case the clearance mostly includes something along the lines of ‘traffic is a XYZ, will depart before you’ or ‘departing traffic is entering runway’. If YOU are the departing traffic, then the call will be ‘XYZ cleared for takeoff runway XX, traffic is a citation on a three mile final’. Which is another way of saying, ‘get outta here PDQ’…..
European clearances seem to take the last com scenario much more seriously at the expense of less efficient runway use. Also everything is designed from an Airbus IFR perspective. It does not seem to matter if a clearance is issued in CAVOK conditions to a SEP which can react if the guy ahead blocks the runway or in CATI to a heavy type which might have much more difficulties.
Once in the US on an ILS in full IMC at Bangor we got an approach clearance. Then we did catch up on the airplene ahead. It was a Falcon and I still don’t know how that thing went probably below 100kt. Then the controller made us fly a 360 halfway down the ILS. What if we had lost communication? We would a run into the guy ahead on a fully valid approach clearance.
On the other hand the European way gets a certain amount of traffic into Friedrichshafen and the US approach gets a whole lot more into Oshkosh…
I always used to think the US usage was odd. But if you compare it with other clearances, ATC is only promising that your trajectory will be clear when you reach the relevant part of it, not that it is fully clear right now.
So why not clear someone to land in the expectation that the runway will be clear when they need it?
Airborne_Again wrote:
Well, yes you can… ATC can apply reduced separation criteria where an aircraft may land even if the previous landing aircraft is still on the runway or a previous departing aircraft is still on/over the runway provided it is sufficiently far away.
Maybe, I don’t know, but that wasn’t what I meant. What I meant was that if you cannot land because the runway is occupied (actually and real), then it doesn’t matter if you have received a clearance or not, the result is the same. You have to do a go around to ovoid a collision.
