I recently bought a simulator for tower controllers (Tower! 2011) and have some questions about the responsibilities of the tower controller:

  1. When an aircraft wants to land at 'my' airport I get contacted once they are established on the approach path and already have a runway assigned ("Tower, N1234 with you runway 26L").
    Unfortunately sometimes it happens that aircrafts are assigned a runway that is actually to short form them to land - which I found out the hard way by getting punished because the plane was not able to stop on the runway.
    Who is responsible to assign the correct runway in real-life, the tower controller or the approach controller? If if were up to the approach controller that would basically be a bug in the simulator.
  2. Who decides which runway exit an aircraft will use after landing?
    Again in the simulator I can advise the aircraft to taxi to the terminal via a certain route ("N1234 taxi to terminal via L4 M4 N4") with L4 being the exit from the runway I want this aircraft to take. Unfortunately the aircrafts - in the simulator - decide which exit they are going to use on their own. So it might happen that the aircraft I assigned the route to exits the runway at exit L5 and therefore cannot comply with my assignment.
    How is that handled in real-life? Does the pilot land the plane and then report back where he is (if I queried the airplane for a position I get a "N1234 is on the ground") or does the tower controller assign an exit that the pilot needs to take - and therefore the simulator would have a bug?
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    $\begingroup$ The pilot can refuse a runway if he doesn't think he can land on it. If he does decide to land while he knows it is too short he is at fault. $\endgroup$ May 6, 2014 at 8:24

3 Answers 3

  1. The tower gives the ultimate clearance to land, though the approach controller (if one is available) assigns a specific approach to a runway in the approach clearance. I'm not sure about the game, however in real life if the runway was too short to land on, the pilot would report being "unable" to use that runway and would be assigned another runway instead. It is not the responsibility of ATC to ensure that the runway is long enough to land on.

  2. Unless there is a NOTAM otherwise noting that a particular exit is unavailable for use, the pilot can slow down at whatever rate to vacate at any particular exit. However, once they've slowed down to taxi speed they should vacate as soon as practicable. The tower controller may request that a pilot vacates at a specific exit, but if they are unable to they will go for another exit.

    After vacating the runway, the pilot notifies the tower that they are clear of the runway at a particular taxiway, and then will be (depending on the airport) be asked to switch to ground or be given taxi instructions.

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    $\begingroup$ notice that #2 is a direct result of Tenerife, where PanAm was assigned an exit and failed to use it, leaving the tower controlers and the KLM crew both in the fog and darkness to make the incorrect assumption that the runway was clear. Just one of the many communications failures that contributed to that accident. $\endgroup$
    – jwenting
    May 6, 2014 at 14:51
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    $\begingroup$ I disagree with point #2. AIM 4-3-20 says to exit at the first available taxiway or as instructed by ATC. To me, that indicates that you are not to continue on the runway to C if you can safely turn at A, even if C would ultimately be more convenient. $\endgroup$
    – Steve V.
    May 6, 2014 at 19:05
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    $\begingroup$ @jwenting Where did you get that from? I can't find any evidence supporting that. It would be strange since the situation was that Pan Am was instructed to use the active runway as a taxiway. I such case (which is clearly different from a landing aircraft as described in the question) the controller could and still can instruct a specific exit which has to be used. Pan Am missed the exit but that was not really relevant to the communication breakdown. They never reported clear of the runway, instead they reported that they were still on the active runway (twice). $\endgroup$
    – DeltaLima
    May 6, 2014 at 19:27
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    $\begingroup$ @SteveV. First available is a bit ambiguous as it depends on how much braking is used. On one hand pilots are not expected to use first achievable (and heat their brakes to the maximum), on the other hand they cannot taxi past a couple of exits at 15 knots. By using tactical breaking crew have some wiggle room on their first available exit. $\endgroup$
    – DeltaLima
    May 6, 2014 at 20:00
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    $\begingroup$ @jwenting Pan Am never reported reaching their exit. (See full transcript). Also the controllers were not operating at night, it was 17:02, sunset was 19:21. What changed as a direct result of the accident was the use of the word take-off which is now used exclusively in the take-off clearance. (KLM took off without take-off clearance). $\endgroup$
    – DeltaLima
    May 6, 2014 at 20:55

The approach controller is responsible for assigning the runway to the aircraft, but the pilot of the aircraft is responsible for verifying the runway is long enough for his aircraft and rejecting the approach clearance if he feels it is unsafe. The tower will ultimately give the landing clearance as they have the detailed picture of what is going on at the runway. Note that it is a landing clearance, not an instruction.

The tower controller can request a runway exit to be used for landing aircraft, however ultimately the pilot is free to choose. If he cannot make an exit or it would require excessive braking a pilot will elect to take a later exit. In general pilots will vacate as soon as practicable not to cause interference with other traffic.

Once the aircraft has vacated the runway, the pilot will be given taxi clearances either from the tower controller or from a ground controller on a separate frequency.


The Tower controls the runways and therefore designates active runways for arriving and departing traffic. Typically this is done based on current surface winds and aircraft type.


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