As the tower controller is responsible for separation of aircraft in the ATA Airport Traffic Area: Also refered to Class D airspace. Normally a 5 mile radius around the airport, from the surface to 2500' AGL. and the active runways, the controller will assign the landing runway to provide a safe and expeditious flow of traffic. At LAX normally the outer runways are used for arrivals, however the controller may assign any runway traffic permitting, if it offers the aircraft an operational advantage. Here are the things you must consider:
Does the aircraft have the winds, altimeter, ceiling and visibility?
Has a runway been assigned?
If the aircraft is VFR and just entering the ATA, does the aircraft have a Bravo clearance?
Are there preceding arrivals before the aircraft?
Will any departing traffic be a factor?
Do we need to apply wake turbulence separation?
Lets examine these in detail.
Does the aircraft have the winds, altimeter, ceiling and visibility? As required, by the 7110.65, the aircraft must be given this information prior to landing. When approach control is online this is normally given to the aircraft from approach. However when radar controllers are offline, you must give this information to the aircraft on initial contact. When the weather is above VFR minimums, you need to give the winds and altimeter, however when the weather is below VFR, the lowest ceiling and visibility must also be reported. As mentioned in “Special Operations due to Weather” when visibility drops below ½ mile or the aircraft is conducting a CATII or III approach, visibility is reported in RVR.
Has a runway been assigned? Again, when online the approach controller normally sequences the arrivals, and because of the distance between the normal landing runways, the approach controller can have aircraft on simultaneous approaches at any time. Unless there’s a separation problem with the arrivals, i.e. the preceding aircraft slowed down where a separation becomes and issue, or traffic permitting the aircraft asks for a different runway for an operational advantage, it’s recommended that you do not switch the landing runway. However the tower controller is responsible to assign the landing runway.
When there is no radar controller online, the tower controller should inform the aircraft on initial contact what runway to expect. This should be based on the current traffic, the aircrafts requested runway, and where the normally park.
Does an arriving VFR aircraft have a Bravo clearance? The tower controller must always be aware of inbound VFR aircraft, as many are flying outside the bravo airspace, and are not in contact with approach. When you have an inbound VFR aircraft contact you, determine their position, decide the best pattern entry, and make sure you give them a bravo clearance BEFORE entering the bravo.
Are there preceding arrivals before the aircraft? When an aircraft is in sequence to follow another, you should provide traffic advisories that informs the pilot where the traffic is located using relative positions of the traffic pattern components, distance, aircraft type, and optionally the livery (or airline). It’s also a good idea to have the pilot report the traffic in sight, although this doesn’t relieve you of the responsibility of separation, the pilots can help you out a lot in this area. Trick is to keep the pilots in the loop, so they know who’s following who, so separation issues are greatly reduced. For example:
“Traffic to follow, a Mooney on left downwind abeam the numbers”
“Traffic, a United 737 5 mile final 25L”
As LAX is a certified radar position, you can also choose to issue traffic advisories using standard radar phraseology, i.e. “traffic, a Cessna 11 o’clock, 5 miles”. Note: As LAX is the only radar certified tower, its recommended you use traffic pattern components and visual landmarks.
If the preceding arrival has been cleared for the option, make sure you consider that the aircraft can make a full stop, and sit on the runway before taking off again. Also you must consider this if your landing aircraft requests the option, and if you have aircraft behind him, you must anticipate the aircraft is going to stop on the runway, and extra spacing needs to be provided.
Will departing traffic be a factor? In addition to maintaining required separation, you must always consider that the landing aircraft could go around at any time (or fly the missed approach if flying the ILS). Always have a plan for such a contingency.
Do we need to apply wake turbulence separation? If the preceding aircraft is a heavy, remember you need to allow 2 minutes between touchdown, and 2 minutes from a departing heavy after the heavy begins his takeoff roll. You must also provide a wake turbulence advisory, for example,
“Caution wake turbulence departing 747 on the parallel”.
It's recommended that you look at the trailing aircraft's ground speed when issuing the landing clearance, as a lot of VATSIM pilots forget that theres a 250 knot speed restriction in the Bravo airspace, as an aircraft flying 300 knots on a five mile final would cross the threshold in one minute!
Now that you have mapped out a strategy, we need to issue the actual landing clearance instruction. If approach is online and hands them off, unless you need to have them land on a different runway, the winds and landing clearance are all that necessary.
“SWA421 winds 240 at 7, runway 24R cleared to land”
Also remember to give the aircraft traffic and wake turbulence advisories and if they are following another aircraft:
“SWA421, traffic a United 747 heavy, 1 mile final runway 24R, caution wake turbulence, winds 240 at 7, runway 24R cleared to land”
Besides the “cleared to land” instruction, as the tower controller, you also have the following options:
“Cleared for the option”: The pilot will request this normally for instructional purposes, which allows the pilot to make a low approach, touch-and-go, stop-an-go, or a full stop. The tower controller must decide if spacing is adequate for this request. Remember, the aircraft could just stop on the runway, and sit there before initiating the takeoff roll again, so if you have an arrival 5 miles behind him, advise the aircraft of the following traffic and if you anticipate inadequate spacing, DENY the option and clear them for a full stop, low approach or touch-and-go. Remember, the OPTION is at YOUR OPTION!
“Long landing approved”: As pilots are normally expected to land within the touchdown zone, this instruction can give the pilot and ATC an operational advantage with light or some large aircraft that will be parking at the other end of the runway. This instruction authorizes the pilot to land at any point on the runway, saving time both for the pilot and ATC eliminating the need for a long taxi to the parking area, relieving the controller the taxiway traffic. As it’s the pilot is responsibility for landing the aircraft safely, this clearance allows the pilot to land on the numbers all the way to the end of the runway.
Two things you must avoid are “cleared for the approach” and “sidestep runway XX” as these are approach control instructions.
As unanticipated events can happen, sometimes you will need the aircraft to land on a different runway than the one that they were initially cleared for. ONLY if the weather is VFR and the pilot reports the airport in sight, you can tell the aircraft to change to the different runway, and should be done as soon as possible, for example:
"AAL123, change runway 25R cleared to land"
If the aircraft is on an instrument approach and doesn't have the field in sight, and the runway is unsafe for landing, instruct the aircraft to fly the missed approach, and a reason why their flying a missed, and to contact the radar controller.