Aerodromes [Annex 14]

Aerodrome Physical Characteristics

An International Airport is one where procedures and facilities for immigration, health and customs are established and operated. They may also exercise controls on persons and cargo entering the state.

- Basic Layout

Movement Area = All the parts intended for the surface movement of aircraft. Includes the manoeuvre area, aprons and any part provided for maintenance.

Manoeuvre Area = That part provided for take off and landing of aircraft and for movement of aircraft on the surface, excluding the apron and maintenance parts.

Apron = Defined portion of an aerodrome where passengers, mail and cargo are loaded and unloaded. (In the US, this is often called the "ramp").

Aeronautical Part = Includes everything (also buildings/facilities) which is not accessible without security control. Often called the "air-side".

- Aerodrome Reference Code

These are used for aerodrome planning and construction purposes. Composed of 2 elements which are related to aeroplane performance and dimensions.


Aerodrome rescue and firefighting categories are based upon the length and width of the largest aircraft that will use that airport.

- Runway Braking Action

Good =  value of 0.4 and above

Med/Good =  value of 0.36 to 0.39

Med = value of 0.30 to 0.35

Med/Poor = value of 0.26 to 0.29

Poor = value of 0.25 and below

UNRELIABLE = reading unreliable

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Aerodrome data

Aerodrome Reference Point = The geographical location of the aerodrome and the centre of its traffic zone (if an ATZ is established)

PCN = Pavement Classification Number. Used to indicate the strength of a runway, taxiway or apron

ACN = Aircraft Classification Number. Expresses the relative effect of an aircraft on a paved area

TORA = The runway length declared available and suitable for the ground run of an airplane taking off

TODA = The length of the TORA plus the length of the clearway, if provided

ASDA = The TORA plus the length of the stopway, if provided, for the acceleration and deceleration of an airplane aborting a takeoff

LDA = The runway length declared available and suitable for landing an airplane

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Taxiways

Rapid Exit Taxiways can be provided where traffic density is high. They will have a maximum speed, determined by the operator (not over 50kts when wet)

Taxiway Curves (widened area) are provided in turns to keep the same clearance between outer wheel and the taxi edge

Holding Bays are provided on very busy airports for aircraft waiting their turn so that the taxiways can be kept clear.

Runway holding position must also be established if the aircraft can interfere with traffic or radio navigation aids (ILS).

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Visual Aids and Markings

An aerodrome shall be equipped with at least one wind direction indicator. A signalling lamp must also be provided at a controlled aerodrome for light signals to aircraft in the air and on the ground.

- Runway Markings (White , may be outlined in black)

Runway designation marking = Provided at the threshold of paved runways

Displaced threshold = (Arrows) Permanently displaced (or "6 months or more"), they can only be used for take off. (Crosses) Indicated unusable for aircraft movements. (Triangles) Indicates unusable for normal movement but can be used as a stopway.

Aiming Point Marker = Indicates the position of the origin of the visual glide slope (PAPI) and the ILS GlidePath transmitter.

Touchdown Zone Markings = Gives the pilot an indication of extent of the usable touchdown area and if it is distance coded, also the length of the touchdown zone remaining. 150m from runway threshold.


- Taxiway and Stand Markings (Yellow , may be outlined in black)

Apron Safety Lines = The ground equipment and vehicles parked behind these lines can be ignored by the pilot or marshaller when parking the aircraft.

Runway Holding Position = There can be more than one, the actual position is also indicated by a mandatory sign. There are 2 possible patterns;

Pattern A: For holding point closest to the runway (Visual take off , non-precision)
Pattern B: When more holdings are provided


- Signs

Signs are provided to give a mandatory instruction, information on a specific location or destination or to provide information as required. They may be illuminated when the RVR is less than 800m or at night.

Mandatory instruction signs = Identifies a location beyond which an aircraft taxiing or vehicle shall not pass unless authorised by the tower. Consists of white letters on a red background.


Information signs = When there is an operational need to identify a specific location or routing. Information signs consists of black lettres on a yellow background and location signs are yellow on a black background.


Fixed distance markers = Indicates the remaining length of the runway, they are white on a black background. Used on runways longer than 4000ft.

Unpaved runway edge markers = When the extent of an unpaved runway is not clearly visible. They can be incorporated in runway lights if they are provided, otherwise they are flat rectangular or conical shaped.

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Aerodrome Lighting

An aerodrome will have an alternate power supply to cope with power failures. Where no such back-up exists, emergency lights are to be available for at least the primary runway.

Aerodrome Beacon = Shows flashes of light (green for land and yellow for water airports). Is a means for pilots to identify an airport at night or low visibility.

- Approach Lighting System

Are patterns of fixed lights of variable intensity, showing white, designed to give the pilot guidance to the threshold of a runway in poor visibility or at night.

- Calvert System (Mostly UK) = 5 bars and a distance coded centreline


- Barrettes (ICAO) = Arrangement of 3 lights or more close together is called a "barrette". The picture below shows such a system with an added crossbar.


1. Simple approach lighting system (non-instrument / non-precision)

Consists of a row of lights on the extended centreline more than 420m from the threshold with a row of lights forming a crossbar at a distance of 300m from it.


2. Precision approach CAT I

Uses the 5 crossbar Calvert system. The row of lights on the extended centreline now extend to more than 900m from threshold. Can also use the ICAO system.


3. Precision CAT II / III

Spreads out over 900m from threshold. Can either us Calvert system for the first part and add Barrettes on the runway or use ICAO system and add a crossbar.


- Precision Approach Path Indicators (PAPI)

Additional to a precision approach, glide path guidance is provided during the visual phase (after Decision Height). Consists of 4 lights showing either red or white. When the runway is used for circling approaches, normally there would be one PAPI on each side.


- Runway Lights

Centreline = Are white lights. They show alternating red and white from 900-300m and they show all red for the last 300m.

Edge lights = Are white lights. A caution zone may be provided over the last 600m where the lights show yellow.

Threshold and wing bar = Unidirectional lights, showing green in the direction of approach.

End lights = Fixed, unidirectional lights showing red in direction of the runway.

Touchdown zone lights = Provided in the touchdown zone of CAT II/III precision approach runways from the threshold to a distance of 900m (if the runway is 1800m or more).

- Taxiway Lights

Centreline = Fixed, variable intensity showing green. Green and yellow are used for intermediate holding position lights (taxiway going over into a runway).

Edge lights = Fixed, variable intensity omni-directional blue coloured.

Stop bars = A row of red lights showing in the direction of taxiing aircraft. An aircraft can only proceed when turned off.

Runway guard lights = Warns pilots and vehicles that they are about to enter an active runway. Installed at the entrance of an active runway. They can either be a group of 2 flashing yellow lights on either side or a row of flashing yellow lights on the taxiway.

With a displaced threshold, the runway edge lights between beginning of runway and displaced threshold shall be red.


Obstacle Markings

- Obstacle Identification Surface (OIS)

A defined surface intended for the purpose of: Determining obstacles which are to be considered for the planning of a departure route and climb gradient or calculation of obstacle clearance altitude/height for an approach procedure.

- Vehicles and mobile objects

Red (or yellowish green) for emergency vehicles. These also require a blue flashing light for use whilst responding to an emergency.

Vehicle obstacle lights are low intensity flashing yellow. Objects with limited mobility (air bridges, etc) are lit with low intensity steady red.

- Fixed Objects

Shall be lit by low, medium or high intensity obstacle lights or a combination.

Low intensity lights = Fixed red (< 45m)

Medium intensity lights = Flashing red (>45m but <150m)

Medium intensity lights used together with high intensity lights = Flashing white

High intensity lights = Flashing White (>150m)

- Signal Area (for VFR traffic)