Section 2 Aerodrome Services

Question 1

An Aerodrome Control unit shall provide:

Answer 1

a) Aerodrome Control Service.
b) Basic Service.
c) Alerting Service.

Question 2

Aerodrome Control Responsibilities

Answer 2

Aerodrome Control is responsible for issuing information and instructions to aircraft
under its control to achieve a safe, orderly and expeditious flow of air traffic and to
assist pilots in preventing collisions between:
a) aircraft flying in, and in the vicinity of, the ATZ;
b) aircraft taking-off and landing;
c) aircraft moving on the apron;
d) aircraft and vehicles, obstructions and other aircraft on the manoeuvring area.
2.2 In order to execute his duties, an aerodrome controller has authority over aircraft,
vehicles and personnel on the manoeuvring area and aircraft moving on the apron.

Question 3

Specific Responsibilities

2.5.1 In addition, Aerodrome Control has the following specific responsibilities:

Answer 3

a) Alerting the safety services;
b) Informing aircraft under its control of any depletion of the aerodrome emergency
services;
c) Providing an Approach Control Service when carrying out functions delegated by
Approach Control;
d) Supplying the following information to Approach Control and, according to unit
instructions, Approach Radar Control:
i) Pertinent data on IFR, Special VFR and VFR traffic including departures, missed
approaches and overdue aircraft;
ii) Appropriate items of essential aerodrome information.
e) Informing the Aerodrome Operator when it becomes apparent that there is a
deterioration in the state of the aerodrome or associated facilities for which the
Aerodrome Operator is responsible;
f) Initiating overdue action at aerodromes where no Approach Control unit is
established.

Question 4

Co-ordination

2.6.1 Aerodrome Control shall co-ordinate with Approach Control:

Answer 4

a) departing IFR flights;
b) arriving aircraft which make their first call on the tower frequency (unless they are
transferred to Approach Control).

2.6.4 Aerodrome Control shall co-ordinate with adjacent aerodromes to ensure that the
traffic circuits do not conflict.

Question 5

Unless specified otherwise in the MATS Part 2, the responsibility for control of a
departing aircraft shall be transferred from Aerodrome Control to Approach Control:

Answer 5

a) in VMC: prior to the aircraft leaving the vicinity of the aerodrome, or prior to the
aircraft entering IMC;
b) in IMC: immediately after the aircraft is airborne.

Question 6

Effect of Weather on Operations Class D
4.3.1 When the reported meteorological conditions at aerodromes in Class D airspace
reduce below the following minima, ATC shall advise pilots of aircraft intending to
operate under VFR to or from such aerodromes, and request the pilot to specify the
type of clearance required:
By day:

Answer 6

• Aircraft other than helicopters: visibility 5 km and/or cloud ceiling 1500 feet.
• Helicopters: visibility 1500 m and/or cloud ceiling 1500 feet.

Question 7

Effect of Weather on Operations Class D
4.3.1 When the reported meteorological conditions at aerodromes in Class D airspace
reduce below the following minima, ATC shall advise pilots of aircraft intending to
operate under VFR to or from such aerodromes, and request the pilot to specify the
type of clearance required:
By night:

Answer 7

By night:

• Aircraft including helicopters: visibility 5 km and/or cloud ceiling 1500 feet.

Question 8

ATC shall not issue any further VFR clearances to aircraft wishing to operate under
VFR to or from an aerodrome in Class D airspace when the reported visibility at the
aerodrome is below:

Answer 8

By day:
• Aircraft other than helicopters: visibility 5 km
• Helicopters: visibility 1500 m
By night:
• Aircraft including helicopters: visibility 5 km

Question 9

Aircraft under the jurisdiction of Aerodrome Control and in receipt of information
critical to the continuing safe operation of the aircraft must be kept informed of any
subsequent changes. For example:

Answer 9

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

Question 10

Define Essential Aerodrome Information

Answer 10

Essential aerodrome information is that concerning the state of the manoeuvring area
and its associated facilities that may constitute a hazard to a particular aircraft. It shall
be issued to pilots in sufficient time to ensure the safe operation of aircraft. This may
include the provision of urgent information to pilots during aircraft take-off and landing
runs.

Question 11

Essential aerodrome information shall include:

Answer 11

a) construction work or maintenance on the manoeuvring area;
b) rough portions of the manoeuvring area and whether marked or not;
c) failure or irregular functioning of the aerodrome lighting system. Defects must be
passed to pilots in the form that they have been reported to the controller.
Controllers should not make assumptions that a particular defect renders an
associated aid unserviceable or not available. The pilot is responsible for deciding
his course of action;
d) failure or irregular functioning of approach aids;
e) aircraft parked close to the runways or taxiways and aircraft engaged in ground
running of engines;
f) depth of snow layers on runways and taxiways, snow piled or drifted on the
manoeuvring area, melting snow and slush, rutted ice and snow;
g) in snow and ice conditions: information concerning sweeping and/or sanding of
runways and taxiways;
h) reports on the estimated braking action determined either by the equipment
described in Chapter 8 or by reports from pilots of aircraft, which have already
landed, including: a description of the prevailing conditions, e.g. standing water,
snow settling; the time of measurement; the type of aircraft if an aircraft report.
When the braking action has been reported as less than good and more than thirty
minutes has elapsed since the previous aircraft report or measurement, the
braking action should be checked before passing details to an aircraft.
The assessment of braking action by use of a brake testing decelerometer (e.g. the
Tapley Meter) is to be carried out solely in conditions of dry snow and ice, gritted
or ungritted;
i) bird formations or individual large birds reported or observed on or above the
manoeuvring area or in the immediate vicinity of the aerodrome and the extent of
any bird dispersal action being carried out. When flocks of birds or single large ones
are seen, the Aerodrome Operator or Bird Control Unit must be informed;
j) warnings of the presence of water on runways (as described in Chapter 7);
k) information on the location and operational status of any arrester gear installation.

Question 12

ADI Responsibility on the apron

Answer 12

Aerodrome Control responsibility on the apron is limited to providing advice and
instructions to assist the prevention of collisions between moving aircraft.

Question 13

ADI Responsibility on the manouvering area

Answer 13

The movements of aircraft, persons or vehicles on the manoeuvring area and the
movement of aircraft on the apron are at all times subject to permission from
Aerodrome Control.

Question 14

The phrase “give way” must not be used to

Answer 14

The phrase “give way” must not be
used in RTF phraseology to vehicles to resolve conflictions between vehicles and
aircraft on the manoeuvring area.

Question 15

When is the RWY considered to be occupied

Answer 15

When aircraft, persons or vehicles have been given permission to cross or occupy a
runway in use, the controller shall, as a positive reminder that the runway is blocked,
display a strip(s) or marker(s) on the part of the flight progress board that is used to
represent the runway.

Question 16

How may SMR be used

Answer 16

Surface movement radar may be used when traffic on the aerodrome cannot be
adequately seen from the control tower during the periods of low visibility or during
the hours of darkness as follows:
a) To monitor the movements of aircraft and vehicles on the manoeuvring area;
b) To provide advice and assistance for the safe and efficient movement of aircraft
and vehicles on the manoeuvring area. This should include the following:
• To ensure that departing aircraft are lined up on the correct runway;
• Determining that a runway is clear of aircraft and vehicles;
• To ascertain that aircraft have commenced take-off run;
• To monitor the positions of traffic in order to facilitate switching of taxiway
lighting;
• To monitor and assist emergency service vehicles when required.

Question 17

Methods of SMR Ident

Answer 17

Before providing guidance to an aircraft/vehicle based on SMR-derived information,
identification shall be established by the use of one of the methods specified below:
a) By correlating the position of a visually observed aircraft/vehicle to that displayed
on the SMR; or
b) By correlating an identified SMR position from another ATS surveillance system
source; or
c) By correlating an SMR position complying with an ATC instruction for a specified
manoeuvre; or
d) By correlating a displayed SMR position to an aircraft/vehicle as reported by radio;
or
e) By correlating a displayed SMR position to an aircraft/vehicle position, e.g. entering
a runway or taxiway, holding position or any position marked on the situation
display.

Question 18

When the pilot of an aircraft requests start-up or taxi clearance the following
information shall be given:

Answer 18

• Runway in use;
• Surface wind direction and speed, including significant variations;
• Aerodrome QNH;
• Outside air temperature (turbine-engine aircraft only);
• Significant meteorological conditions, e.g. RVR or marked temperature inversion.
9.2 Those items which are known to have been received by the pilot may be omitted.

Question 19

Rules for taxi instructions for heavy A/C

Answer 19

Heavy aircraft are not to be given clearance or instructions that would require the use
of more than normal power for taxiing or for entry on to the runway. Heavy aircraft,
when at the holding position, are not to be cleared for an immediate take-off.

Question 20

Can you taxi on the active RWY

Answer 20

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

Question 21

Can instuct an A/C to cross an illuminated stop bar

Answer 21

Controllers are not to instruct aircraft or vehicles to cross illuminated red stop-bars
used at runway and intermediate taxiway holding positions. The Aerodrome Operator
may decide, on the grounds of safety, that inoperable stop-bars and associated
taxiways be withdrawn from service and alternative routes used where practicable.

Question 22

When can you deselect a stop bar

Answer 22

Where illuminated red stop-bars are used at runway holding positions they are only to
be de-selected when clearance has been given for an aircraft or vehicle to enter the
runway. If a conditional clearance has been issued in respect of a landing aircraft the
stop-bar must not be deselected until the landing aircraft has passed the position at
which the vehicle or aircraft will enter the runway. This requirement may be satisfied
either visually by the controller or by the use of SMR/SMGCS as specified in MATS

Question 23

Can an Aircraft hold on the end of the runway if another aircraft has
been cleared to land.

Answer 23

Aircraft shall not be permitted to hold on the end of the runway if another aircraft has
been cleared to land. Aircraft will hold clear of the runway at the marked holding
position or, if one is not provided, not closer than those distances from the runway
centerline as described in CAP 168 Chapter 3.

Question 24

How do you guard against pilots misinterpreting a clearance message as permission to takeoff

Answer 24

To guard against pilots misinterpreting a clearance message as permission to takeoff,
after an aircraft has been instructed to hold at a runway holding position and a
clearance message is passed, the clearance message shall be prefixed with a
repetition of the appropriate holding instruction.

Question 25

When can you give multiple line up clearances

Answer 25

Line-up instructions may be issued to more than one aircraft at different points on the
same or crossing runways provided that:
a) it is during daylight hours;
b) all aircraft are continuously visible to the aerodrome controller;
c) all aircraft are on the same RTF frequency;
d) pilots are advised of the number of aircraft ahead in the departure sequence, and
the position/runway from which these aircraft will depart;
e) the physical characteristics of the runway do not render preceding aircraft in the
departure sequence invisible to succeeding aircraft on the same runway.

Question 26

When given the instruction “cleared for immediate take-off” it is expected that the
pilot will act as follows:

Answer 26

a) At the holding position, taxi immediately on to the runway and commence take-off
without stopping the aircraft. (Not to be given to Heavy aircraft);
b) If already lined up on the runway, take-off without delay.
c) If an immediate take-off is not possible, he will advise the controller.

Question 27

An aircraft on an IFR flight is not to be given take-off clearance until:

Answer 27

a) The ATC clearance from Area Control (if required) has been passed and
acknowledged; and
b) Approach Control have authorised its departure and any specific instructions have
been passed to the aircraft, e.g:
i) Turn after take-off;
ii) Track to make good before turning onto desired heading;
iii) Level(s) to maintain.

Question 28

Critical speed for A/C taking off

Answer 28

80kts, normally reached approx 300m into T/O roll

Question 29

Designated Positions in the Traffic Circuit

Answer 29

Position 1 Aircraft reports on ‘downwind’ leg when abeam upwind end of the
runway.
Position 2 Aircraft reports ‘late downwind’ if it is on the downwind leg, has been
unable to report ‘Downwind’ and has passed the downwind end of the
runway.
Position 3 Aircraft reports ‘base’ leg (if required).
Position 4 Aircraft reports ‘final’. Clearance to land issued here.
Position 5 Aircraft reports ‘long final’ (between 8 and 4 miles) when aircraft is on a
straight-in approach.

Question 30

When aircraft are using the same runway, a landing aircraft may be permitted to touch
down before a preceding landing aircraft which has landed is clear of the runway
provided that:

Answer 30

a) the runway is long enough to allow safe separation between the two aircraft and
there is no evidence to indicate that braking may be adversely affected;
b) it is during daylight hours;
c) the preceding landing aircraft is not required to backtrack in order to vacate the
runway;
d) the controller is satisfied that the landing aircraft will be able to see the preceding
aircraft which has landed, clearly and continuously, until it has vacated the runway;
and
e) the pilot of the following aircraft is warned. Responsibility for ensuring adequate
separation rests with the pilot of the following aircraft.

Question 31

When can a controller send an a/c around

Answer 31

A landing aircraft, which is considered by a controller to be dangerously positioned on
final approach, shall be instructed to carry out a missed approach. An aircraft can be
considered as dangerously positioned when it is poorly placed either laterally or
vertically for the landing runway.

Question 32

Aircraft in the traffic circuit shall be controlled in accordance with the procedures
above except that controllers are not required to apply the separation minima
described in those paragraphs to:

Answer 32

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

Question 33

The information derived from the ATM may be used to:

Answer 33

a) determine the landing order, spacing and distance from touchdown of arriving
aircraft;
b) assist in applying longitudinal separation for departing aircraft;
c) enable the controller to confirm that the initial track of a departing aircraft conforms
with the clearance issued;
d) provide information to aircraft on the position of other aircraft in the circuit or
carrying out an instrument approach.

Question 34

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

Answer 34

a) following identification, validate SSR codes of departing aircraft and verify
associated Mode C read-outs;
b) monitor the progress of overflying aircraft identified by Approach Radar Control to
ensure that they do not conflict with the tracks of arriving or departing aircraft;
c) establish separation between departing aircraft;
d) pass traffic information;
e) establish separation in the event of a missed approach;
f) assist in taking initial corrective action when the separation between arriving
aircraft becomes less than the prescribed minima.
Provided that:
i) the controller has undertaken specified training;
ii) the controller is only providing an Air Control Service and a separate Ground
Control Service is being provided by another controller on a separate frequency;
and
iii) the procedures are detailed in MATS Part 2.
Units where Air Control and GMC are combined may apply to the CAA to be exempt
from ii).

Question 35

Low Approach Restrictions

If the runway in use is occupied by aircraft or vehicles, an approaching aircraft that has
requested a low approach or a touch and go, may be cleared to carry out a low
approach restricted to a height….

Answer 35

not below 400 feet above the threshold elevation. In
such circumstances, the pilot is to be informed of the aircraft or vehicles on the
runway.

Additionally, the aircraft or vehicle on the runway is to be informed of the
aircraft carrying out the low approach.

For aircraft operating on the aerodrome QNH, the low approach altitude restriction is
to be based on 400ft plus threshold elevation, rounded up to the nearest 50ft.

The runway in use shall be kept clear of aircraft and vehicles if an approaching aircraft
is likely to descend below 400 feet above the threshold elevation.

Question 36

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

Answer 36

a) routine operational limitations, e.g. runway maintenance;
b) unforeseen hazards to aircraft operations, e.g. deteriorating surface conditions,
obstructions etc. Specifically, the Aerodrome Operator will make decisions
regarding:
i) the closure or re-opening of the aerodrome;
ii) the withdrawal or return to use of runways, taxiways and associated lighting
aids;
iii) the revision of declared distances;
iv) any marking required in connection with the above;
v) initiating NOTAM action to promulgate changes in serviceability.

Question 37

Rules on release of racing pigeons

Answer 37

In agreement with the Royal Racing Pigeon Association, it has been agreed that a
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 date of release. In addition, the ATC unit should be notified by telephone
at least 30 minutes before release time, in order to confirm, where practicable, the
number of birds due to be liberated and the intended destination and direction of
flight. If necessary, 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.

Question 38

Rules on light displays

Answer 38

Specific guidelines apply to light displays using lasers and searchlights within 500
metres either side of extended runway centrelines within ten miles of an aerodrome.
Within three miles of an aerodrome but not on the extended centreline, the same
guidelines apply but with the addition that any light should not stray towards the
aerodrome or the extended centreline. In both cases, information should be passed
to any affected aircraft. If a pilot requests that the lights are extinguished or if ATC
consider this necessary, then action should be taken without delay.

Question 39

Rules on Fireworks

Answer 39

Guidelines have also been laid down for fireworks displays which should be limited to
a height of 1500 ft above ground level and should not take place within 500 metres
either side of the extended runway centreline within five miles of an aerodrome, or
within two miles radius of an aerodrome. However, published guidelines apply if a
fireworks display is to take place within these parameters.

Question 40

Define Windshear

Answer 40

Windshear is a sustained change in the wind velocity along the aircraft flight path,
which occurs significantly faster than the aircraft can accelerate or decelerate.
1.2 Windshear can occur at any level, but it is low-level windshear, occurring from the
surface to a height of approximately 1500 feet which can cause problems of sufficient
magnitude to affect the control of aircraft in departure or final approach phases of
flight.

Question 41

Conditions conducive to windshear

Answer 41

Controllers should be alert to the possibility of the existence of windshear in the
following circumstances:
a) The presence of frontal/squall/thunderstorm activity in the vicinity of the
aerodrome.
b) The presence of low level inversions where the surface wind will be significantly
different from that at only a few hundred feet above the ground.
c) Local terrain or buildings considered in relation to wind speed and direction; such
large obstructions can cause windshear as well as the more usual turbulence and
gusts.

Question 42

Whenever a pilot reports windshear conditions to ATC…..

Answer 42

….the information shall be
relayed to subsequent inbound and outbound aircraft until confirmation is received
that the condition no longer exists.

Question 43

Reports from pilots on windshear should contain the following information:

Answer 43

a) A warning of the presence of windshear;
b) The height or height band where the shear was encountered;
c) The time at which it was encountered;
d) Details of the effect of the windshear on the aircraft, e.g. speed gain or loss,
vertical speed tendency, change in drift.

Question 44

Define Prevailing visibility

Answer 44

Prevailing visibility is defined as the visibility value that is reached or exceeded within
at least half the horizon circle or within at least half of the surface of the aerodrome.
These areas could comprise contiguous or non-contiguous sectors.

Question 45

Reporting of Prevailing Visibility

Answer 45

The prevailing visibility at an observing station will always be reported. Where the
visibility in any direction is less than the prevailing visibility and less than 1500 metres
or less than 50% of the prevailing visibility, the lowest visibility observed will also be
reported. The general direction of the area of lower visibility will be indicated by
reference to one of the eight points of the compass. If the lowest visibility is observed
in more than one direction, then the most operationally significant direction will be
reported.
2.2 When the visibility is fluctuating rapidly and the prevailing visibility cannot be
determined, only the lowest visibility will be reported, with no indication of direction.

Question 46

Routine Aerodrome Surface Inspections

Answer 46

At least one regular inspection should be made daily. At aerodromes which are open
24 hours this should be as soon as practicable after first light. At non-24 hour stations
the inspection should take place before flying commences. A further inspection
should take place before night flying.

Question 47

Additional surface inspections should be made:

Answer 47

a) at cessation of work on the manoeuvring area;
b) when a runway not previously inspected is brought into use;
c) following an aircraft accident;
d) following an abandoned take-off by a turbine engined aircraft due to engine
malfunction, or by any aircraft due to burst tyres;
e) during snow and ice conditions as frequently as weather conditions warrant;
f) when considered necessary by ATC, the Aerodrome Operator or as detailed in
local instructions.

Question 48

RWY inspection Normal Conditions
Normal Conditions
2.7.1 A check should be made to ascertain whether or not:

Answer 48

a) the runways, stopways, clearways, taxiways and holding areas are free from
obstructions, collections of loose stones, etc;
b) temporary obstructions that exist on, or adjacent to, the runways or taxiways are
properly marked or lighted;
c) bad ground (particularly on non-runway aerodromes) is adequately marked;
d) runway indicator boards, traffic signs, boundary markers, etc., are serviceable and
in position.
2.7.2 A note should be taken of the exact position of any obstruction or unserviceability
observed. Any of the above conditions that are encountered should be reported to the
section whose responsibility it is to deal with them.

Question 49

DRY

Answer 49

The surface is not affected by water, slush, snow, or ice.
NOTE: Reports that the runway is dry are not normally to be
passed to pilots. If no runway surface report is passed, pilots will
assume the surface to be dry.

Question 50

DAMP

Answer 50

The surface shows a change of colour due to moisture.
NOTE: If there is sufficient moisture to produce a surface film or
the surface appears reflective, the runway will be reported as WET.

Question 51

WET

Answer 51

The surface is soaked but no significant patches of standing water
are visible.
NOTE: Standing water is considered to exist when water on the
runway surface is deeper than 3mm. Patches of standing water
covering more than 25% of the assessed area will be reported as
WATER PATCHES.

Question 52

WATER PATCHES

Answer 52

Significant patches of standing water are visible.
NOTE: Water patches will be reported when more than 25% of the
assessed area is covered by water more than 3mm deep

Question 53

FLOODED

Answer 53

Extensive patches of standing water are visible.
NOTE: Flooded will be reported when more than 50% of the
assessed area is covered by water more than 3mm deep.

Question 54

Reported runway area

Answer 54

This area may differ slightly from one
runway to another but will approximate to the central two-thirds of the width of the
runway extending longitudinally from a point 100 m before the aiming point to 100 m
beyond the aiming point for the reciprocal runway.

Question 55

The following terms are to be used to describe deposits on the surface of an
aerodrome:

Answer 55

a) Ice – water in its solid state, it takes many forms including sheet ice, hoar frost and
rime;
b) Dry snow – a condition where snow can be blown if loose or, if compacted by
hand, will fall apart again upon release;
c) Compacted snow – snow which has been compressed into a solid mass, that
resists further compression and will hold together or break-up into chunks if picked
up;
d) Wet snow – a composition which, if compacted by hand, will stick together and
tend to, or does, form a snowball;
e) Slush – a water saturated snow which, with a heel and toe slap down action with
the foot against the ground, will be displaced with a splatter;
f) Associated standing water – standing water produced as a result of melting
contaminant in which there are no visible traces of slush or ice crystals.

Question 56

The following changes, relating only to runway conditions, are classed as significant

Answer 56

a) Any change in surface deposit, i.e. snow turned to slush, water to ice, etc., and the
effect on braking action where appropriate;
b) Changes in depth greater than the following: 20 mm for dry snow, 10 mm for wet
snow, 3 mm for slush;
c) Any change in the available length or width of runway(s) of 10 per cent or more;
d) Any change in the type of deposit or extent of coverage which requires
reclassification in item F of the SNOWTAM;
e) Any change in the distance apart of snowbanks from the criteria declared to be the
value from which reporting begins;
f) Any change in the serviceability of runway lighting caused by obscuring of the
lights, with particular reference to the threshold;
g) Any other conditions known to be significant according to local circumstances.

Question 57

1.2 An Aerodrome Control unit provides services principally to aircraft….

Answer 57

flying with visual
reference to the surface in, and in the vicinity of, the ATZ and operating on the
manoeuvring area. It is normally a separate unit but may be combined, either
temporarily or permanently, with an Approach Control unit.

Question 58

12. 8.2 An aerodrome controller may, after co-ordination with Approach Control:
    a) expedite departing aircraft by….

Answer 58

suggesting a take-off direction which is not into
wind. The pilot has the right to reject the suggestion;

b) reduce the overall delay to traffic by altering the order in which he clears aircraft to
take-off;

c) 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 59

2.6.2 Approach Control will co-ordinate with Aerodrome Control:

Answer 59

a) aircraft approaching to land; if necessary requesting landing clearance;
b) arriving aircraft which are to be cleared to visual holding points;
c) aircraft routeing through the traffic circuit.
2.6.3 Approach Control may delegate the responsibility for co-ordination to Approach Radar
Control.