4. Air Control ("Muscat Tower")
4.1 General provisions
Tower control (TWR/AIR) is responsible for all aerodrome movements on runways and their associated taxiways. TWR shall also ensure separation in the control zone between IFR and IFR traffic as well as IFR and VFR traffic is maintained. Traffic information shall also be provided so pilots of VFR traffic can maintain visual separation between themselves.
4.2 Preferential runways
The preferred calm wind configuration is departing and arriving runway 26R, which shall be used up to a 5-knot tailwind. Otherwise, runway 08L will be used. Tower shall pick the configuration that is used in real life (by checking flight radar) whenever possible.
Warning
At the time of writing, the southern runway (08R/26L) is currently closed, as per updated NOTAMs. This is due to the restructing of Muscat aerodrome. This runway shall not be used, except for crossing taxiing aircraft between taxiways E1 and D1.
4.3 Departure procedures
Runway 08L/26R features three departure points per configuration. The standard departure points are full length on each runway. There should not be a performance difference between Y1 and Y2, and Y7 and Y8 respectively so they can be assigned to optimize the departure rate. Y3 and Y6 are intersection departure points that shall only be assigned after confirmation by the pilot that aircraft performance is sufficient.
4.3.2 Line up clearances
Conditional line up instructions shall include the traffic that the aircraft is to follow, as well as the word “behind” at the beginning and end of the transmission. It is recommended to only have a maximum of two conditional line up clearances active at once.
Example
Controller: "SWR243, behind the departing Oman Air A330, runway 26R line upand wait behind."
If aircraft have not yet reached the holding point where they are expected to line up at, ATC shall reiterate the cleared holding point.
Example
Controller: "OMA298 via Y7, line up and wait runway 26R"
4.3.3 Take-off clearances
Aircraft shall be cleared for take-off once adequate separation exists, as provided in 4.3.4.
Example
Controller: "OMA8KC, wind 280 degrees 4 knots, runway 26R cleared for take-off."
4.3.4 Separation requirements
4.3.4.1 General
Aircraft shall be separated on departure in compliance with standard IFR departure separation minima.
Succeeding aircraft with the same Muscat FIR exit point shall be separated by a minimum of two minutes, except as provided in 4.3.4.2.
A VFR aircraft following a VFR departure may be instructed to maintain visual separation with preceding aircraft and given take-off clearance if no wake turbulence separation minima exists.
4.3.4.2 Muscat FIR flow control procedure
Two Muscat departures with the same Muscat FIR/Mumbai FIR boundary exit point and the same cruising level must adhere to a minimum departure interval of three minutes. During events, the appointed flow manager may adjust these as necessary.
4.3.4.3 Low visibility and IMC
During low visibility operations and during IMC in general, departing aircraft shall not be cleared for take-off when there is an arriving aircraft within 4 nm of the landing runway threshold.
4.3.5 IFR handoff procedure
Departing IFR aircraft shall be handed off to the Muscat TMA controller or –if not online- Muscat Control. Aircraft shall be handed off when passing 800ft to ensure adequate time for a frequency change and avoid a level off on departure.
4.3.6 Stopping a departure
Aircraft that have commenced their take-off roll may be instructed to stop immediately to avert a collision due to a runway incursion or any other dangerous situation.
It must be noted though, that the instruction to stop must be given early enough such that the aircraft does not reach its decision speed. The stopping distance of an aircraft is also significant. Therefore, aerodrome controllers must be vigilant and remain aware of the location of traffic at all times as well as runway incursion hotspots.
Example
Controller: "FDB687, Stop immediately, I say again stop immediately, runway incursion."
For aircraft that have been given a take-off clearance, but have not yet started the roll, they shall be instructed to hold position and the take-off clearance must be cancelled along with the reason.
Example
Controller: "FDB687, hold position, cancel takeoff clearance, I say again cancel takeoff clearance, aircraft entering the runway."
4.4 Arrival Procedures
4.4.1 Preferred exit points
During periods of increased arrival or departure activity, aircraft shall be instructed to vacate at the rapid exit taxiway for the runway in use. These are Y4 and Y5 respectively.
4.4.2 Separation requirements
4.4.2.1 General
While the radar controllers are responsible for separating and sequencing arriving aircraft, the TWR controller shall still ensure that minimum separation (>3nm) is maintained until the preceding aircraft crosses the runway threshold.
4.4.2.2 Speed control
If it is apparent that minimum separation may not exist, TWR may use a tactical reduction in aircraft speed.
Example
Controller: "OMA1784, reduce to final approach speed."
4.4.2.3 Visual separation
Aircraft may be instructed to maintain own separation visually, if speed control alone will not resolve the conflict. This shall only be done in VMD and in agreement with the pilot. If no other solutions are practical, the succeeding aircraft shall be instructed to go around.
4.4.3 Go-around instruction
4.4.3.1 General go-around procedure
Should a runway at any time become unsuitable for an aircraft landing, or separation minima is not met, aircraft shall be instructed to go-around.
Example
Controller: "UAE797, go around, I say again, go around. Acknowledge."
At Muscat, instructions in case of a go-around are usually assigned by Muscat Approach. However, Muscat Tower may reiterate these if necessary and if these change, after coordination with Muscat Radar. Once aircraft have acknowledged the instruction and are observed to be safely climbing away, they shall be transferred to Muscat TMA.
Example
Controller: "UAE797, (fly runway heading, climb to altitude 3,000ft,) contact Muscat Radar 121.200."
4.4.4 Arrival taxi procedures
In accordance with taxi procedures laid down in 3.4, aircraft shall be provided an intial taxi clearance to ensure they are kept moving, such that the relevant rapid exit taxiway (RET) is kept clear for the next arrival.
The intiial taxi instruction shall include instructions to taxi "LEFT" or "RIGHT" onto the relevant taxiway, as appropriate, and a hold short instruction at a suitable intermediate holding point.
Example
Controller: "OMA8KC, taxi right on W, hold short of V"
Once aircraft have been observed to be taxiing and completely clear of the RET, transfer of control shall be initiated to GMC, provided there will be no conflicts with other traffic.
4.5 VFR procedures
The Muscat control zone is unique because it is class C and not class D like many other CTRs. This means that TWR is responsible for separating VFR and IFR traffic by at least 3nm or greater if wake turbulence separation is required. VFR traffic does not have to be separated from other VFR traffic but traffic information should be provided wherever possible.
4.5.1 VFR departures
Once VFR aircraft are ready for departure, they shall be cleared for take-off in sequence. As they begin their crosswind turn, they shall be instructed to report leaving the control zone or to report any other Visual Reporting Point on their route as deemed appropriate.
If aircraft are exiting into uncontrolled airspace, they shall be instructed to remain outside controlled airspace and monitor Unicom. If they are entering Muscat TMA airspace, they shall be handed off to the Muscat TMA controller approximately one minute before leaving the control zone.
4.5.2 VFR traffic remaining in the circuit
TWR control is responsible for managing circuit traffic. Circuits will always be conducted to the north of the airfield. Once aircraft are ready for departure they shall be cleared for take-off in sequence. As they begin their crosswind turn, they shall be instructed to report when they are on downwind with their intentions
Example
Controller: "A-TT, report downwind with intentions"
Aircraft may request a touch and go, a stop and go, a low approach or a full stop landing. Once TWR is aware of the aircraft’s request, they may be sequenced to the runway, with due consideration given to runway occupancy time.
Aircraft on downwind shall be passed the following information: • Sequence • Traffic information if applicable
Example
Controller: "A-TT, number 1, report final runway 26R."
Controller: "A-TT, runway 30R, cleared to land/touch and go/low approach."
4.5.3 VFR arrivals
Inbound VFR aircraft shall be instructed to contact TWR with enough time such that two-way radio communication has been established before aircraft enter the control zone. On first contact TWR will pass instructions on how to enter the CTR, the runway in use and the QNH.
Example
Controller: “A4O-TT, Muscat Tower, Enter control zone via Cement Plant East, Runway 26R, 2,000 feet VFR, QNH 1017”
Once the traffic is closer to the aerodrome, they shall be given circuit joining instructions. VFR arrivals from the south can either be given a direct base for the respective runway or if there is a delay expected they should make a midfield crossing to join the normal circuit in the north of the aerodrome.
Example
Controller: "A-TT, join base runway 26R" or
Controller: "A-TT, cross midfield, join right-hand downwind runway 26R"
VFR arrivals may be denied entry into the control zone during times of increased IFR arrival activity and instructed to hold outside controller airspace awaiting further instructions. VFR aircraft may also be told to orbit at any VRP inside the CTR.
4.6 Secondary Muscat Tower position
Muscat AIP has defined a secondary (south) tower position, for the southern runway (08R/26L). At this time, the runway remains closed as per updated NOTAMs. This section of the SOP will be updated when this changes.