Section 2, Chapter 1 - Aerodrome Control

Question 1

What services are provided by an Aerodrome Control unit and to whom are these services principally provided?

Answer 1

An Aerodrome Control unit provides:

• Aerodrome Control Service
• Basic Service
• Alerting Service

These services are principally provided to aircraft flying with visual reference to the surface in and around the Aerodrome Traffic Zone (ATZ) and operating on the manoeuvring area.
The unit is typically separate but may be combined with an Approach Control unit either temporarily or permanently.

Question 2

What are the primary responsibilities of Aerodrome Control?

Answer 2

Aerodrome Control issues information and instructions to achieve a safe, orderly, and expeditious flow of air traffic with the objectives of:

Preventing collisions between:

• Aircraft flying in, and in the vicinity of, the ATZ.
• Aircraft taking off and landing.
• Aircraft and vehicles, obstructions, and other aircraft on the manoeuvring area.
  Note: Aerodrome Control shares responsibility for collision prevention with pilots and vehicle drivers as per RoA Regulations.
• Assisting in preventing collisions between aircraft on the apron.

Question 3

What authority and observation responsibilities do aerodrome controllers have?

Answer 3

Aerodrome controllers have authority over aircraft, vehicles, and personnel on the manoeuvring area and aircraft moving on the apron. They must maintain a continuous watch on all flight operations in and around the aerodrome, as well as vehicles and personnel on the manoeuvring area. This can be done through direct out-of-the-window observation or indirect observation using a CAA-approved visual surveillance system.

Question 4

How can Aerodrome Control be divided, and what are the responsibilities of each division?

Answer 4

Aerodrome Control can be divided into:

Air Control:

• Provides services for preventing collisions between aircraft flying in, and in the vicinity of, the ATZ and aircraft taking off and landing.
• Has absolute authority over all movements on active runways and their access points.

Ground Movement Control:

• Provides services for preventing collisions between aircraft and vehicles, obstructions, and other aircraft on the manoeuvring area, and assisting in preventing collisions between aircraft on the apron, except on active runways and their access points.

Clearance Delivery Officer (CDO):

• Positions may be established at aerodromes to relay ATC departure clearances with approved procedures detailed in MATS Part 2.

Question 5

What are the specific additional responsibilities of Aerodrome Control?

Answer 5

Aerodrome Control has the following specific responsibilities:

• Notifying emergency services as per local instructions.
• Informing aircraft under its control of any depletion of the aerodrome emergency services.
• Providing an Approach Control Service when delegated by Approach Control.
• Supplying pertinent data on IFR, Special VFR, and VFR traffic, including departures, missed approaches, and overdue aircraft, as well as essential aerodrome information to Approach Control and Approach Radar Control according to unit instructions.
• Informing the Aerodrome Operator of any deterioration in the state of the aerodrome or associated facilities.
• Initiating overdue action at aerodromes where no Approach Control unit is established.

Question 6

What restriction is placed on Aerodrome Control when Approach Control instructs IFR flights to contact them?

Answer 6

Approach Control may instruct approaching IFR flights to contact Aerodrome Control before transfer of control is effective. Aerodrome Control shall not issue any instructions or advice that would reduce the separation established by Approach Control until the aircraft are flying with visual reference to the surface.

Question 7

What are the co-ordination responsibilities between Aerodrome Control and Approach Control?

Answer 7

Aerodrome Control shall co-ordinate with Approach Control for:

• Departing IFR flights.
• Arriving aircraft that make their first call on the tower frequency (unless transferred to Approach Control).

Approach Control will co-ordinate with Aerodrome Control for:

• Aircraft approaching to land, requesting landing clearance if necessary.
• Arriving aircraft cleared to visual holding points.
• Aircraft routing through the traffic circuit.

Additional Co-ordination Responsibilities:

• Approach Control may delegate co-ordination responsibility to Approach Radar Control.
• Aerodrome Control shall co-ordinate with adjacent aerodromes to ensure traffic circuits do not conflict.

Question 8

When should the responsibility for control of a departing aircraft be transferred from Aerodrome Control to Approach Control?

Answer 8

The responsibility for control of a departing aircraft should be transferred from Aerodrome Control to Approach Control as follows:

• In VMC: Prior to the aircraft leaving the vicinity of the aerodrome or entering IMC.
• In IMC: Immediately after the aircraft is airborne.

Question 9

What additional responsibilities do controllers have regarding airspace classification?

Answer 9

Controllers must provide minimum services according to the classification of the airspace where the aerodrome and associated Aerodrome Traffic Zone (ATZ) are located, in addition to their other responsibilities.

Question 10

What procedure should be followed when reported visibility consists of two values?

Answer 10

When reported visibility consists of two values, the lower value should be used to determine whether to implement specific operational procedures.

Question 11

What must ATC do when meteorological conditions at aerodromes in Class D airspace reduce below specific visibility and cloud ceiling thresholds?

Answer 11

When meteorological conditions at aerodromes in Class D airspace reduce below a ground visibility of 5 km and/or a cloud ceiling of 1500 ft, ATC must advise pilots of aircraft intending to operate under VFR and request the pilot to specify the type of clearance required.

Question 12

What are the exceptions and procedures for issuing VFR clearances in Class D airspace when visibility and cloud ceiling are below specific thresholds?

Answer 12

In Class D airspace, ATC should not issue VFR clearances when ground visibility is less than 5 km and/or cloud ceiling is less than 1500 ft, except for:
* Helicopters with specific callsigns (Police, Helimed, Rescue, etc.), SAR training flights as per MATS Part 2, or rail track inspection flights.

Exceptions are provided by:
* UK General Permission ORS4 No. 1477 for VFR flight at night.
* UK General Exemption ORS4 No. 1576 for Police, HEMS, SAR flights, including SAR training flights.
* UK General Exemption ORS4 No. 1577 for powerline, pipeline, and rail track inspection flights.

Competent observers for meteorological conditions assessment include:
* Holders of valid EASA Flight Crew Licences, National Flight Crew Licences, and related Certificates.
* Student pilots-in-command (SPIC) who have passed the theoretical knowledge examination in meteorology within the last two years.

Additional Notes:
When reported ground visibility consists of two values, the lower value is used for determining procedures.
Procedures for operations into subsidiary aerodromes are detailed in MATS Part 2.

Question 13

What are the requirements and procedures for Low Visibility Procedures (LVP) at aerodromes?

Answer 13

Aerodromes wishing to operate in poor visibility or available for instrument approaches in low cloud conditions must develop and maintain Low Visibility Procedures (LVP) as detailed in CAP 168. Controllers must advise pilots of the implementation and subsequent cancellation of LVP at an aerodrome.

Question 14

What traffic information and instructions must Aerodrome Control provide to aircraft?

Answer 14

Aerodrome Control must provide traffic information and instructions whenever necessary for safety or upon pilot request. Specifically, they must provide:

• Generic traffic information to help VFR pilots safely integrate with other aircraft.
• Specific traffic information appropriate to the stage of flight and risk of collision.
• Timely instructions to prevent collisions and enable safe, orderly, and expeditious flight within and in the vicinity of the ATZ.

Local procedures for aircraft integration in the vicinity of the aerodrome are detailed in MATS Part 2.

Question 15

What subsequent changes must Aerodrome Control inform aircraft about to ensure safe operation?

Answer 15

Aerodrome Control must inform aircraft under its jurisdiction of any subsequent changes critical to safe operation, including:

• Significant changes in meteorological and runway conditions.
• Changes in essential aerodrome information.
• Changes in the notified operational status of approach and landing aids.

Question 16

What constitutes essential aerodrome information, and when should it be provided to aircraft?

Answer 16

Essential aerodrome information includes details about the state of the manoeuvring area and associated facilities that may pose a hazard to an aircraft. It should be provided to every aircraft unless it is known that the aircraft has already received the information from other sources, such as NOTAM, ATIS broadcasts, or suitable signals.
This information must be given in sufficient time for the aircraft to use it properly, and hazards should be identified as distinctly as possible, including during take-off and landing runs.

Question 17

What information is considered essential for aerodrome operations as per CAP 493?

Answer 17

Essential aerodrome information includes:

• Construction work or maintenance on the manoeuvring area.
• Rough or broken portions of the manoeuvring area and their marking status.
• Failure or irregular functioning of the aerodrome lighting system, as reported to the controller.
• Failure or irregular functioning of approach aids.
• Aircraft parked close to the runways or taxiways and aircraft engaged in ground running of engines.
• Water, snow, slush, ice, or frost on a runway, taxiway, or apron.
• In snow and ice conditions: details about anti-icing or de-icing chemicals, contaminants, sweeping, and/or sanding.
• Bird formations or large individual birds on or above the manoeuvring area or near the aerodrome, and any bird dispersal actions.
• Information on the location and operational status of any arrester gear installation.

Question 18

What are the responsibilities and procedures for controlling surface traffic at aerodromes according to CAP 493?

Answer 18

Permissions Required: Movements of aircraft, persons, or vehicles on the manoeuvring area and the movement of aircraft on the apron require permission from Aerodrome Control at all times.
Apron Control: Aerodrome Control provides advice and instructions to prevent collisions between moving aircraft on the apron, especially when parts of the apron are out of sight from the control room. Procedures include:
* Clearing one aircraft to taxi and giving a second aircraft instructions to follow or give way.
* Refusing further movement requests until the first aircraft is visible to the controller.
* Clearing one aircraft to taxi and asking for reports when clear of the apron or past a reference point before clearing another movement.

Vehicle Priorities: Vehicles must give way to aircraft taking off, landing, taxiing, or being towed. Emergency vehicles responding to an aircraft in distress have priority over all other surface traffic, and other movements should be halted to avoid impeding them. The phrase “give way” should not be used in RTF phraseology for resolving conflicts between vehicles and aircraft on the manoeuvring area.

Question 19

What are the procedures for crossing runways as per CAP 493?

Answer 19

• Clearance to Cross: Normally withheld until no confliction exists. May be given subject to aircraft landing or taking off, with sufficient information for identification and related to one movement only.
• Frequency Use: Crossing instructions for a runway-in-use must be on the same frequency as take-off and landing clearances. Frequency change instructions are issued after the aircraft vacates the runway.
• Report Vacated Instruction: Included in the clearance to cross, unless Aerodrome Control has continuous sight of the aircraft or vehicle crossing.

Question 20

What are the procedures for managing runway occupancy according to CAP 493?

Answer 20

• Display Reminder: When aircraft, persons, or vehicles are permitted to cross or occupy a runway in use, controllers must display a strip or marker on the flight progress board to indicate the runway is blocked.
• Alternative Method: If flight progress boards are not used, an equivalent method should be implemented to effectively show runway occupancy.
• RTF Frequency for Vehicles: Vehicles operating on an active runway must be transferred to an RTF frequency that allows them to hear transmissions to and from aircraft using that runway.

Question 21

What are the key procedures for preventing runway incursions according to CAP 493?

Answer 21

• Definition: A runway incursion is any occurrence involving the incorrect presence of an aircraft, vehicle, or person on the protected area of a surface designated for aircraft take-off and landing.
• Factors Contributing to Incursions: One major factor is pilots and airside vehicle drivers being uncertain of their position on the manoeuvring area, especially near or on the runway.
• Actions When Uncertain:
  1. Pilots or vehicle drivers uncertain of their position should stop and notify the ATS unit, providing their last known position.
  2. If on a runway, they should vacate it via a nearby suitable taxiway if possible, then stop and await further instructions.
• Controller Responsibilities: Controllers must issue instructions to eliminate or mitigate potential hazards when an aircraft or vehicle is in the wrong position.
• Safety Measures: ANSPs may define in MATS Part 2 the conditions under which aircraft are considered to have vacated the runway for additional safety.

Question 22

What is the procedure for controlling non-radio equipped aircraft and vehicles in low visibility conditions according to CAP 493?

Answer 22

In low visibility conditions, where non-radio equipped aircraft and vehicles cannot be controlled by light signals, their movement on the manoeuvring area should normally be prohibited, except for emergency services vehicles.

Question 23

How should traffic lights installed for vehicle control on taxiways be operated according to CAP 493?

Answer 23

Traffic lights for controlling vehicles on taxiways should be operated by Aerodrome Control or the air controller. They must ensure that the red stop signal is displayed in adequate time for drivers to observe and obey the instructions.

Question 24

What considerations should controllers take into account regarding jet blast and propeller slipstream according to CAP 493?

Answer 24

Controllers must consider the hazards of jet blast and propeller slipstream when issuing instructions and clearances on the aerodrome. Even at ground idle, large aircraft can produce localized wind velocities strong enough to cause damage. Particular care is needed when issuing multiple line-up clearances on the same runway, ensuring that aircraft later in the departure sequence are not subjected to jet blast or propeller slipstream from preceding departures.
Research indicates the affected area behind a large aircraft with engines at ground idle can extend up to 600 meters.

Question 25

What information must be provided to a pilot when they request start-up or taxi clearance according to CAP 493?

Answer 25

When a pilot requests start-up or taxi clearance, the following information must be given:

• Runway in use.
• Surface wind direction and speed, including significant variations.
• Aerodrome QNH.
• Outside air temperature (for turbine-engine aircraft only).
• Significant meteorological conditions (e.g., RVR or marked temperature inversion).

Items known to have been received by the pilot may be omitted. Time checks, accurate to the nearest minute, should be provided upon request.

Question 26

Why is issuing clear and concise taxi instructions crucial according to CAP 493?

Answer 26

Issuing clear and concise taxi instructions is crucial because the visibility from an aircraft flight deck is limited. When taxiing, pilots rely heavily on Aerodrome Control to determine the correct taxi route.

Essential aerodrome information must be provided to help pilots prevent collisions with parked aircraft and obstructions on or near the manoeuvring area.

Question 27

What specific taxi clearance instructions should be given to heavy aircraft according to CAP 493?

Answer 27

Heavy aircraft should not be given clearance or instructions requiring the use of more than normal power for taxiing or runway entry.

Additionally, heavy aircraft at the holding position should not be cleared for an immediate take-off.

Question 28

What is the guideline for using the active runway for taxiing purposes according to CAP 493?

Answer 28

In the interests of safety, the use of the active runway for taxiing purposes should be kept to a minimum.

Question 29

What are the procedures for managing illuminated red stop-bars according to CAP 493?

Answer 29

• Crossing Prohibition: Controllers must not instruct aircraft or vehicles to cross illuminated red stop-bars at runway and intermediate taxiway holding positions. Inoperable stop-bars and associated taxiways may be withdrawn from service by the Aerodrome Operator for safety reasons, with alternative routes used where practicable.
• De-selecting Stop-Bars: Illuminated red stop-bars at runway holding positions should only be de-selected when clearance has been given for an aircraft or vehicle to enter the runway. If a conditional clearance has been issued for a landing aircraft, the stop-bar must not be de-selected until the landing aircraft has passed the entry point for the vehicle or aircraft. This can be verified either visually by the controller or using SMR/SMGCS as specified in MATS Part 2.

Question 30

What is the procedure for managing illuminated red stop-bars when a conditional line-up clearance has been issued for succeeding departing aircraft from the same runway holding position according to CAP 493?

Answer 30

When a conditional line-up clearance has been issued to a succeeding departing aircraft from the same runway holding position, the illuminated red stop-bar may remain de-selected, provided that the aircraft will be the next movement on that runway. Meteorological restrictions applicable to this procedure are specified in MATS Part 2.

Question 31

Under what conditions can an aircraft be instructed to cross an illuminated stop-bar when it is inoperable according to CAP 493?

Answer 31

Under exceptional circumstances, an aircraft may be instructed to cross an illuminated inoperable stop-bar if the following conditions are met:

• The affected runway or intermediate holding position and the aircraft are visible to the controller. This can be verified using SMR/SMGCS as specified in MATS Part 2 or local alternate solutions based on risk assessment if the aerodrome is not SMR/SMGCS equipped.
• The phraseology used must ensure the pilot or driver understands the crossing instruction applies only to the specific inoperable stop-bar, and conditional clearances should not be used.
• Additional MATS Part 2 procedures may be required if local risk assessments indicate further mitigation measures are necessary.
• Extra care must be taken if this procedure is used during Low Visibility Operations or at night, as the green taxiway centerline lights linked to the stop-bar will not be available.

Question 32

What are the key procedures and considerations for taxi clearance limits according to CAP 493?

Answer 32

• Specific Clearance Limit: All taxi clearances must include a specific clearance limit, which should be a location on the manoeuvring area or apron.
• Crossing Runways: When clearing an aircraft to the holding point of the runway-in-use, the clearance should explicitly state whether the aircraft is permitted to cross intersecting runways. If a clearance to cross cannot be given, the clearance limit and route must exclude the runway and any routes beyond it. The phrase “hold short” may be used to emphasize that an aircraft is not authorized to cross an intermediate runway.
• VFR Departure Check: If an aircraft wishes to depart in airspace where VFR flight is permitted and flight details are unknown, the pilot should be asked, “Are you departing VFR?”
• “Follow the…” Phrase: While useful, this phrase could lead to an aircraft inadvertently crossing a holding position or entering an active runway. Controllers should use caution when issuing instructions containing “follow the…”, especially near active runways or holding positions.
• Visual Misidentification: Controllers must be alert to the potential for visual misidentification of aircraft, particularly when an aircraft’s livery does not match its callsign.

Question 33

What are the procedures for aircraft awaiting take-off according to CAP 493?

Answer 33

• Holding Position: Aircraft should not hold at the end of the runway if another aircraft has been cleared to land. They must hold clear of the runway at the marked holding position or, if none exists, at the distances described in CAP 168 Chapter 3.
• Clearance Message: To prevent misinterpretation of a clearance message as permission to take off, the clearance message must be prefixed with a repetition of the appropriate holding instruction after an aircraft has been instructed to hold at a runway holding position.
• Conditional Clearances: Conditional clearances should not be used for movements affecting the active runway unless the aircraft or vehicles involved can be seen by both the controller and the pilot or driver. Conditional clearances must relate to one movement only and, in the case of landing traffic, to the first aircraft on approach. When multiple aircraft are at a holding position adjacent to a runway, a conditional clearance may be given to an aircraft regarding another ahead in the departure sequence, ensuring no ambiguity about the aircraft’s identity.

Question 34

Under what conditions can line-up instructions be issued to more than one aircraft at different points on the same or crossing runways according to CAP 493?

Answer 34

Line-up instructions may be issued to more than one aircraft at different points on the same or crossing runways provided that:

• It is during daylight hours.
• All aircraft are continuously visible to the aerodrome controller.
• All aircraft are on the same RTF frequency.
• Pilots are advised of the number of aircraft ahead in the departure sequence and the position/runway from which these aircraft will depart.
• The physical characteristics of the runway do not render preceding aircraft in the departure sequence invisible to succeeding aircraft on the same runway.

Question 35

What should be included in the line-up instruction when an aircraft will line up at a position other than for a full-length runway departure according to CAP 493?

Answer 35

When line-up will take place at a position other than for a full-length runway departure, the intermediate holding position designator shall be included in the line-up instruction. Controllers may also include holding position designators in any clearance to line-up as considered appropriate.

Question 36

What are the key responsibilities and procedures for issuing take-off clearance according to CAP 493?

Answer 36

• Controller Responsibilities: The aerodrome controller must issue take-off clearance and advise pilots of any variations in surface wind or other significant meteorological changes. When a pilot requests the instantaneous surface wind, the term “instant” is used to indicate that the reported wind is not the two-minute average.
• Runway Designator: Take-off clearance must include the departure runway designator unless specified otherwise in MATS Part 2.
• Issuing Clearance: Take-off clearance can be issued when the aircraft is at or approaching the holding position for the runway in use or when it is lined up on or entering the runway in use. Controllers may include holding position designators as appropriate.
• Separate Clearance: Take-off clearance should be issued separately from any other clearance message. If a revised clearance or post-departure instructions need to be passed to an aircraft lined up on the runway, they should be prefixed with an instruction to hold position.
• Take-off Timing: An aircraft must not begin take-off until the preceding departing aircraft is seen to be airborne or has reported ‘airborne’ by RTF, and all preceding landing aircraft have vacated the runway in use.
• Turn Instructions: A departing aircraft should not be given instructions to make a turn before reaching a height of 500 ft, except for light aircraft.

Question 37

What procedures should be followed for issuing departure clearances according to CAP 493?

Answer 37

Clarity in Clearance: To avoid confusion with ground movement instructions, ATC clearance should start with “after departure” if there is potential for initial confusion (e.g., with a turn) to prevent pilots from taking off without a take-off clearance.
IFR Flight Clearance: For aircraft on an IFR flight, take-off clearance must not be given until:
* The ATC clearance from Area Control (if required) has been passed and acknowledged.
* Approach Control has authorized the departure and any specific instructions have been passed to the aircraft, such as:
1. Turn after take-off.
2. Track to make good before turning onto the desired heading.
3. Levels to maintain.

Question 38

What actions are expected from a pilot when given the instruction “cleared for immediate take-off” according to CAP 493?

Answer 38

When given the instruction “cleared for immediate take-off,” the pilot is expected to:

• At the Holding Position: Taxi immediately onto the runway and commence take-off without stopping the aircraft. (This instruction should not be given to HEAVY or SUPER aircraft.)
• Already Lined Up: Commence take-off without delay.
• If Immediate Take-off is Not Possible: Advise the controller immediately.

Question 39

What measures can an aerodrome controller take to expedite departing aircraft according to CAP 493?

Answer 39

An aerodrome controller, after coordination with Approach Control, may:
* Take-off Direction: Suggest a take-off direction that is not into the wind to expedite departure. The pilot has the right to reject this suggestion.
* Order of Take-off: Alter the order in which aircraft are cleared for take-off to reduce overall delay.
* VMC Climb for IFR Flights: When ATS surveillance systems are not available, clear departing IFR flights to climb VMC and maintain their own separation until a specified time, location, or level, if reports indicate that this is possible.

Question 40

What should a pilot of a departing aircraft consider regarding wake turbulence according to CAP 493?

Answer 40

The pilot of a departing aircraft may request a delay in take-off due to the danger of wake turbulence from the preceding aircraft. This danger is particularly significant for aircraft commencing the take-off run part of the way along the runway.

Question 41

What are the procedures and considerations for cancelling a take-off clearance according to CAP 493?

Answer 41

• Before Take-off Run: If the take-off clearance must be cancelled before the take-off run has commenced, the pilot should be instructed to hold position and acknowledge the instruction.
• During Take-off Run: If cancellation is necessary after the take-off run has commenced, the pilot should be instructed to stop immediately and acknowledge the instruction. This should only occur if continuing the take-off poses serious and imminent danger.
• Risk Awareness: Controllers should be aware of the risk of aircraft overrunning the runway if the take-off is abandoned late. This is a particular concern for large aircraft or those operating near performance limits.
• Speed Considerations: As aircraft speed increases, the risks of abandoning take-off increase. For modern jet aircraft, take-off clearance should generally only be cancelled at speeds above 80kt if there is a serious collision risk or substantial debris on the runway. The typical distance for reaching 80kt is around 300m from the start of the take-off roll.
• Emergency Preparedness: Controllers should be ready to declare an emergency or provide assistance if an aircraft abandons its take-off and experiences issues like overheated brakes.

Question 42

What are the procedures for aircraft joining a traffic circuit according to CAP 493?

Answer 42

• Clearance to Enter Circuit: Issued when the aircraft is still some distance from the aerodrome to allow the pilot to conform with the traffic circuit. Information about landing direction or runway in use and any other necessary instructions is provided.
• Standard Overhead Join: Aircraft may be cleared to position overhead the aerodrome at 2,000 ft above aerodrome elevation. When cleared to descend, the aircraft routes to the dead side of the circuit, descends to circuit height, crosses the upwind end of the runway in use at circuit height, and then positions into the existing traffic pattern to report downwind. Any variance from this procedure must be specified in MATS Part 2, and the phraseology “standard overhead join” must not be used in such circumstances.
• Unauthorised Entry: If an aircraft enters the traffic circuit without proper authorization, the possibility of an emergency must be considered. The aircraft should be permitted to land if its actions indicate that intention, and other aircraft should be instructed to give way if necessary.

Question 43

What are the key procedures for issuing landing clearances according to CAP 493?

Answer 43

• Runway Designator: Landing, low approach, and touch-and-go clearances must include the designator of the landing runway unless specified otherwise in MATS Part 2.
• Separation from Departing Aircraft: A landing aircraft should not be permitted to cross the beginning of the runway on its final approach until a preceding aircraft departing from the same runway is airborne, unless specific procedures approved by the CAA are in place.
• Instantaneous Surface Wind: When a pilot requests the instantaneous surface wind, the term “instant” should be used to indicate that the reported wind is not the two-minute average.

Question 44

Under what conditions can a landing aircraft be permitted to touch down before a preceding landing aircraft has vacated the runway according to CAP 493?

Answer 44

A landing aircraft may be permitted to touch down before a preceding landing aircraft has vacated the runway if the following conditions are met:

• The runway is long enough to allow safe separation between the two aircraft, with no evidence indicating that braking may be adversely affected.
• It is during daylight hours.
• The preceding landing aircraft does not need to backtrack to vacate the runway.
• The controller is satisfied that the landing aircraft can clearly and continuously see the preceding aircraft until it has vacated the runway.
• The pilot of the following aircraft is warned, and responsibility for ensuring adequate separation rests with the pilot of the following aircraft.

Question 45

Under what conditions should a controller instruct a landing aircraft to carry out a missed approach according to CAP 493?

Answer 45

A controller should instruct a landing aircraft to carry out a missed approach if the aircraft is considered to be dangerously positioned on final approach. This can occur when the aircraft is poorly placed either laterally or vertically for the landing runway.

Question 46

What are the guidelines for issuing instructions to aircraft in the final stages of approaching to land according to CAP 493?

Answer 46

With the exception of instructions to go-around, controllers should not issue instructions to aircraft in the final stages of approaching to land that would require deviation from the expected flight path unless exceptional and overriding safety considerations apply. The final approach represents a high workload period for pilots, and unusual situations or emergencies can be particularly demanding during this time.

Question 47

What exemptions from separation minima are allowed for aircraft in the traffic circuit according to CAP 493?

Answer 47

Controllers are not required to apply the separation minima to:

• Aircraft in formation with respect to other aircraft in the same formation.
• Aircraft operating in different areas or lanes on aerodromes equipped with runways suitable for simultaneous landings or take-offs.
• Aircraft operating under military necessity as determined by the appropriate authority.

Question 48

What are the uses of an Aerodrome Traffic Monitor (ATM) according to CAP 493?

Answer 48

An Aerodrome Traffic Monitor (ATM) may be used to:

• Determine the landing order, spacing, and distance from touchdown of arriving aircraft.
• Assist in applying longitudinal separation for departing aircraft.
• Enable the controller to confirm that the initial track of a departing aircraft conforms with the clearance issued.
• Provide information to aircraft on the position of other aircraft in the circuit or carrying out an instrument approach.

Operation of an ATM is not associated with a particular rating and must not be used as an ATS surveillance system to provide Approach Radar Services unless authorized by the CAA.

Question 49

What additional functions can an Aerodrome Traffic Monitor (ATM) perform when approved by the CAA, and under what conditions according to CAP 493?

Answer 49

When approved by the CAA, an ATM may also be used to:

• Validate SSR codes of departing aircraft and verify associated Mode C read-outs following identification.
• Monitor overflying aircraft identified by Approach Radar Control to ensure they do not conflict with the tracks of arriving or departing aircraft.
• Establish separation between departing aircraft.
• Pass traffic information.
• Establish separation in the event of a missed approach.
• Assist in taking initial corrective action when separation between arriving aircraft becomes less than the prescribed minima.

Conditions:

• The controller must have undertaken specified training.
• The controller must be providing only an Air Control Service, with a separate Ground Control Service provided by another controller on a separate frequency.
• Procedures must be detailed in MATS Part 2.

Exemption:
Units where Air Control and GMC are combined may apply to the CAA to be exempt from the requirement for separate controllers and frequencies.

Question 50

What factors determine the selection of the runway-in-use according to CAP 493?

Answer 50

• Runway-in-use Definition: Indicates the runway or landing direction selected by Aerodrome Control as most suitable at any particular time, usually aligned with the surface wind direction.
• Wind Considerations: Normally, the runway-in-use should be aligned with the surface wind direction. For light and variable surface wind conditions, the 2,000 ft wind should also be considered.
• Additional Factors: Aerodrome Control should consider traffic patterns, runway lengths, available approach aids, and significant meteorological conditions when selecting the runway-in-use. Multiple runways may be in use simultaneously at certain aerodromes.
• Out of Wind Runway Use: May be selected for reasons such as operational efficiency, noise abatement, and other specific operational requirements.

Question 51

What are the considerations for selecting a runway for noise abatement purposes according to CAP 493?

Answer 51

• Noise Abatement Objective: Runways may be nominated to avoid noise-sensitive areas during initial departure and final approach phases of flight.
• Landing Guidance: A runway should not be selected for noise abatement purposes for landing unless visual or instrument glide path guidance is available.
• Wind Limits: Noise abatement should not determine runway selection if the crosswind component (including gusts) exceeds 15 kt or the tailwind component (including gusts) exceeds 5 kt.
• Additional Parameters: Additional parameters for when noise abatement should not be a determining factor must be agreed with the aerodrome licensee and included in MATS Part 2, considering:
  1. Degree and type of runway surface contamination.
  2. Minimum visibility and cloud ceiling.
  3. Other weather conditions, such as wind shear or thunderstorms.
• Pilot Discretion: If a pilot, for safety reasons, considers a noise abatement runway unsuitable, they may refuse it and request another runway. Controllers must inform pilots of the expected delay for a runway change.

Question 52

What procedures should be followed when changing runways according to CAP 493?

Answer 52

• Avoiding Changes: As far as practicable, avoid changing the assigned runway for aircraft on approach or taxiing for departure to minimize additional cockpit workload.
• Informing of Tailwind: When departing or approaching with a tailwind, inform the aircraft of the tailwind component if available or provide a caution and ask for their intentions using the phraseology:
  1. “(Callsign) tailwind (XX) knots, report your intentions?”
  2. “(Callsign) caution tailwind, report your intentions?”
• Early Notification: Notify anticipated runway changes as early as practicable, including the expected time of the change. Add relevant information on ATIS if available.
• Informing Relevant Parties: If a runway change is necessary, Aerodrome Control, after consultation with Approach Control, shall inform:
  1. Aircraft under their control.
  2. Aerodrome Fire Service.
  3. Contractors working on the aerodrome who will be affected.
  4. Other agencies according to local instructions.

Question 53

What are the responsibilities of the Aerodrome Operator regarding the operational status of the aerodrome according to CAP 493?

Answer 53

The Aerodrome Operator is responsible for decisions regarding the operational status of the aerodrome, including the apron and manoeuvring area, in respect of:

• Routine operational limitations, such as runway maintenance.
• Unforeseen hazards to aircraft operations, like deteriorating surface conditions and obstructions.

Specifically, the Aerodrome Operator will make decisions regarding:

• The closure or re-opening of the aerodrome.
• The withdrawal or return to use of runways, taxiways, and associated lighting aids.
• The revision of declared distances.
• Any marking required in connection with the above.
• Initiating NOTAM action to promulgate changes in serviceability.

Question 54

What actions should the ATC Unit take regarding the operational status of the aerodrome according to CAP 493?

Answer 54

• Immediate Reporting: Inform the Aerodrome Operator immediately if reports or observations indicate a hazard to aircraft movement on the apron or manoeuvring area.
• Interim Decisions: During the Aerodrome Operator’s assessment, the controller should decide the appropriate action based on the circumstances:
  1. Runway Vicinity Obstruction:
  a. Withhold take-off and landing clearances if the obstruction is within the cleared and graded area of the runway.
  b. Withhold clearances if there is any doubt about the obstruction’s position, advising pilots of the reason and the obstruction’s position and nature.
  2. Obstruction Outside Cleared Area: If the obstruction is outside the cleared and graded area but near the apron or manoeuvring area, inform the pilot of the obstruction’s position and nature. The pilot decides whether to continue operations.
• Operational Status Communication: Once the Aerodrome Operator decides the operational status of the apron or manoeuvring area, they will inform ATC. Inform the parent ACC of any situations that may restrict aerodrome operations.

Question 55

What are the procedures for conducting repair or installation work on the manoeuvring area according to CAP 493?

Answer 55

Briefing by ATC or Aerodrome Operations:

• Methods of access to the working area.
• The area in which vehicles may operate.
• The runway-in-use and the effects of any changes.
• Methods of obtaining permission to cross the runway in use.
• Signals or methods indicating that vehicles and personnel must leave the manoeuvring area.

Authorization and Record Keeping:

• The representative of the working party must possess an authorization to work on the aerodrome issued by the Aerodrome Operator.
• This authorization must be counter-signed by the senior controller after the briefing.
• A copy of the authorization should be retained, or a record of the briefing entered in the ATC Watch Log.

Question 56

What are the procedures for runway inspections according to CAP 493?

Answer 56

• Responsibility: MATS Part 2 will specify whether the Aerodrome Operator or another delegated agency is responsible for runway inspections.
• Post-Incident Inspections: After any incident or suspected incident on a runway involving tyre failure, aircraft structural failure, or turbine engine malfunction, the runway must be inspected before any other aircraft can use it.
• Arranging Inspections: At aerodromes where the ATC unit is not responsible for surface inspections, runway inspections must be arranged through the Aerodrome Operator. If special arrangements exist for the ATC unit to conduct inspections, they should follow the instructions in Chapter 6.

Question 57

How should ATC co-operate with the Aerodrome Fire Service and Aerodrome Operator regarding routes through the manoeuvring area according to CAP 493?

Answer 57

ATC should co-operate with the Aerodrome Fire Service and Aerodrome Operator in pre-planning preferential routes through the manoeuvring area. Controllers must ensure they are familiar with these routes.

Question 58

How is the fire service category of an aerodrome determined according to CAP 493?

Answer 58

The fire service category of an aerodrome is assessed based on the length of the longest aircraft expected to use it. The specific categories are detailed in Section 5 of the manual.

Question 59

What are the procedures for handling changes in the level of Rescue and Fire Fighting Services (RFFS) protection at aerodromes according to CAP 493?

Answer 59

• Notification of Changes: The Aerodrome Operator will notify the appropriate ATC unit of any changes in the RFFS protection level, allowing ATC to inform arriving and departing aircraft. ATC responsibilities are limited to disseminating this information to flight crew.
• Unplanned Reductions: ATC units must ensure that unplanned reductions in RFFS category are notified to flight crew via ATIS or directly by RT. Upon receiving such information, flight crew will decide whether to continue their flight or divert based on their Company Standard Operating Procedures. Aircraft are normally expected to divert if the available RFFS category does not meet the required level for their aircraft type, as described in CAP 168.
• Exceptions: Exceptions to the expected diversion include emergency landings and situations where, in the pilot’s opinion, diverting or holding may introduce a more significant hazard. Controllers should continue to provide normal ATS and clearances in response to flight crew intentions.

Question 60

What are the requirements for practice exercises and drills involving ATC and the Aerodrome Fire Service according to CAP 493?

Answer 60

• Coordination and Cooperation: Rapid and coordinated action in the event of a crash requires close cooperation between ATC and the Aerodrome Fire Service, with frequent rehearsal of procedures detailed in Aerodrome Emergency Orders.
• Realistic Drills: ATC, in consultation with the Aerodrome Fire Service, must assist in providing frequent practice emergencies, ensuring they are as realistic as possible.

Question 61

What procedures must the Aerodrome Fire Service follow for testing vehicles or carrying out exercises on the manoeuvring area according to CAP 493?

Answer 61

• Clearance and Instructions: The Aerodrome Fire Service must obtain clearance and any special instructions from Aerodrome Control before testing vehicles or conducting exercises on the manoeuvring area.
• Cooperation and Instruction: Arrangements must be made in cooperation with the Aerodrome Fire Officer for ATC to provide instruction to Aerodrome Fire Service personnel regarding the light and visual signals used on an aerodrome.

Question 62

What are the additional duties of the Aerodrome Fire Service and how should emergencies be handled according to CAP 493?

Answer 62

• Extraneous Duties: At certain aerodromes, the Aerodrome Fire Service may undertake additional duties, provided these do not interfere with their primary function.
• Special Services: The Aerodrome Fire Service may be called for special services such as attending accidents, pumping out flooded premises, or clearing fuel spillages. If considered an emergency and within the radius of action, attendance should be immediate.
• ATC Notification: ATC must be informed of any emergency and advised of any depletion of emergency services. If services are depleted, the Watch Supervisor at the parent ACC must be informed.

Question 63

What are the procedures for notifying and coordinating the release of racing pigeons near a licensed aerodrome according to CAP 493?

Answer 63

• Advance Notification: Proposed liberation of racing pigeons within 13 km of a licensed aerodrome should be notified to the Aerodrome Operator or air traffic control provider at least fourteen days prior to the release date.
• Confirmation Call: The ATC unit should be notified by telephone at least 30 minutes before the release time to confirm the number of birds, the intended destination, and the direction of flight.
• Delay Request: The ATC manager or senior controller may request a delay in the liberation by up to 30 minutes, or longer in exceptional circumstances, for traffic purposes.