Annex 14 and the aerodrome picture
Annex 14 standardises aerodrome physical characteristics and visual aids so a pilot can interpret an unfamiliar runway, taxiway or apron without inventing local meanings.
Operational areas
| Term | Meaning |
|---|---|
| Movement area | The manoeuvring area plus aprons and aircraft-maintenance movement areas. |
| Manoeuvring area | Runways and taxiways used for take-off, landing and surface movement, excluding aprons and maintenance areas. |
| Apron | The area for loading, unloading, fuelling, parking and servicing aircraft. |
| Runway | A defined rectangular area prepared for landing and take-off along its length. |
| Taxiway | A defined path linking one part of a land aerodrome with another. |
Wind and landing-direction indication
An aerodrome has at least one wind direction indicator visible from the air and movement area, positioned clear of misleading turbulence. At least one should be illuminated for night use. A landing direction indicator, where provided, is a conspicuous T. It shows the direction to be used for landing and take-off.
Signal lamp and signal area
A controlled aerodrome tower has a signalling lamp capable of red, green and white signals. The signal area, where provided, is an even horizontal surface at least 9 m square with a contrasting colour and a white border at least 0.3 m wide. It is placed so it can be seen from all azimuths above 10 degrees over the horizontal when viewed from 300 m.
The aerodrome reference code
The reference code links the critical aeroplane to aerodrome dimensions. It is a planning tool, not a method for calculating runway length or pavement strength.
Element 1, the code number
| Code number | Aeroplane reference field length |
|---|---|
| 1 | Less than 800 m. |
| 2 | 800 m or more but less than 1,200 m. |
| 3 | 1,200 m or more but less than 1,800 m. |
| 4 | 1,800 m or more. |
Reference field length is the minimum take-off field length required at maximum certificated take-off mass, sea level, standard atmosphere, still air and zero runway slope, using the approved flight manual or equivalent manufacturer data.
Element 2, the code letter
| Letter | Wingspan | Outer main gear wheel span |
|---|---|---|
| A | Less than 15 m | Less than 4.5 m. |
| B | 15 m to less than 24 m | 4.5 m to less than 6 m. |
| C | 24 m to less than 36 m | 6 m to less than 9 m. |
| D | 36 m to less than 52 m | 9 m to less than 14 m. |
| E | 52 m to less than 65 m | 9 m to less than 14 m. |
| F | 65 m to less than 80 m | 14 m to less than 16 m. |
Runway, strip, RESA, clearway and stopway
The paved runway is only one rectangle in a larger protected system. Each surrounding area has a separate purpose and must not be counted as usable runway unless its definition allows it.
| Area | Purpose and principal dimensions |
|---|---|
| Runway strip | Includes the runway and stopway, reduces damage after a runway excursion and protects overflying aircraft. It extends at least 60 m beyond the threshold and runway or stopway end for codes 2, 3 and 4 and code 1 instrument runways; 30 m for code 1 non-instrument runways. |
| RESA | Beyond the strip end, reduces damage after undershoot or overrun. At least twice runway width and at least 90 m long. Recommended length is 240 m for codes 3 and 4, and 120 m for codes 1 and 2. |
| Clearway | A controlled rectangular area beyond TORA over which initial climb may occur. It begins at the TORA end, is no longer than half TORA and extends at least 75 m each side of the extended centre line. |
| Stopway | A prepared rectangular surface beyond TORA on which an aeroplane can stop after a rejected take-off. It has the same width as its runway. |
Runway and strip widths
Runway width depends on code number and letter. Typical large-aeroplane values include 45 m for code 4C, 4D and 4E, and 60 m for code 4F. Instrument runway strips extend laterally 75 m each side for code 1 or 2 and 150 m each side for code 3 or 4. Non-instrument strip values are 30, 40, 75 and 75 m each side for code numbers 1 through 4.
Taxiway geometry
Taxiways permit safe and expeditious movement, with strength suitable for the aeroplanes using them. Straight widths rise from 7.5 m for code A to 25 m for code F. A rapid-exit taxiway normally intersects at 25 to 45 degrees, preferably 30 degrees, and is designed for wet-condition turn-off speeds of 50 kt for code 3 or 4 and 35 kt for code 1 or 2.
The four declared distances
Declared distances state exactly how much surface or obstacle-clear climb path is available for each performance calculation.
| Distance | Definition in operational terms | Usual relationship |
|---|---|---|
| TORA | Length available and suitable for the ground run of an aeroplane taking off. | The basic take-off-run length. |
| TODA | Length of TORA plus any clearway available for the initial climb. | TORA plus clearway, subject to the published value. |
| ASDA | Length of TORA plus any stopway available for stopping after a rejected take-off. | TORA plus stopway. |
| LDA | Length declared available and suitable for the ground run of an aeroplane landing. | Starts at the landing threshold, so a displaced threshold reduces LDA in that direction. |
Work the geometry
For a 2,400 m runway with a 300 m clearway and 200 m stopway beyond the take-off end, TORA is 2,400 m, TODA is 2,700 m and ASDA is 2,600 m. If the landing threshold is displaced 250 m from the start, LDA in that direction is 2,150 m. Always use the declared values in aeronautical information because intersections, displaced thresholds and local limitations can change the simple geometry.
Marking colours, intersections and runway identity
Runway markings are white. Taxiway, runway turn-pad and aircraft-stand markings are yellow. Bali states that apron safety lines are red in India.
Which marking continues
At a runway crossing, markings of the more important runway continue except its side stripe, while the other runway's markings are interrupted. Priority is precision approach runway, then non-precision runway, then non-instrument runway. At a runway and taxiway intersection, runway markings continue and taxiway markings are interrupted.
Runway designation
The two-digit designation is the whole number nearest one tenth of magnetic north when viewed on approach. A single digit receives a leading zero. Parallel runways add letters in left-to-right order as viewed on approach. Two use L and R; three use L, C and R. Four or more divide into adjacent sets using the nearest and next-nearest runway numbers.
Centre line
A paved runway has a white centre line between the designation markings. A stripe plus its gap is 50 m to 75 m. Each stripe is at least as long as the gap or 30 m, whichever is greater. Minimum stripe width is 0.90 m for precision category II and III, 0.45 m for non-precision code 3 or 4 and precision category I, and 0.30 m for other non-precision and non-instrument cases.
| Magnetic approach track | Designation | Reason |
|---|---|---|
| 004 degrees | 36 | Runway numbers use magnetic direction divided by ten; zero becomes 36. |
| 046 degrees | 05 | 4.6 rounds to 5, written with two digits. |
| 094 degrees | 09 | 9.4 rounds to 9. |
| 275 degrees | 28 | 27.5 rounds to 28. |
Thresholds and displaced thresholds
The threshold is the beginning of runway available for landing. Its marking identifies that landing limit, while arrows explain usable pavement before a displaced threshold.
Threshold piano keys
Threshold stripes begin 6 m from the threshold and are arranged symmetrically about the runway centre line. A paved instrument runway carries them. They also apply to paved non-instrument code 3 or 4 runways intended for international commercial air transport.
| Runway width | Number of threshold stripes |
|---|---|
| 18 m | 4. |
| 23 m | 6. |
| 30 m | 8. |
| 45 m | 12. |
| 60 m | 16. |
Displaced threshold
A threshold displaced from the runway extremity is marked by a transverse white stripe at least 1.80 m wide. White arrows on the runway point toward it. With a temporary displacement, earlier markings are obscured and the centre-line markings before the temporary threshold are converted to arrows. Pavement before a permanently displaced threshold may remain usable for taxi and take-off in the applicable direction, but not for touchdown from that approach.
Side stripes
Runway side stripes define the edges where runway and shoulder or surrounding terrain lack contrast. A precision approach runway should have them regardless of contrast. Each stripe lies along the runway edge, or 30 m from the centre line if runway width exceeds 60 m. Recommended overall width is at least 0.90 m for a runway 30 m or more wide and at least 0.45 m on a narrower runway.
Aiming point and touchdown-zone markings
Aiming-point blocks give a conspicuous visual target. Touchdown-zone pairs add distance and alignment cues on precision runways.
Aiming point
Two conspicuous white rectangles are provided at each approach end of a paved instrument runway with code number 2, 3 or 4. They are also recommended where extra conspicuity is desirable on specified runways. If a visual approach slope indicator is installed, the start of the aiming-point marking coincides with its visual approach-slope origin.
| Landing distance available | Start from threshold | Typical block length |
|---|---|---|
| Less than 800 m | 150 m | 30 m to 45 m. |
| 800 m to less than 1,200 m | 250 m | 30 m to 45 m. |
| 1,200 m to less than 2,400 m | 300 m | 45 m to 60 m. |
| 2,400 m or more | 400 m | 45 m to 60 m. |
Touchdown zone
Touchdown-zone markings are pairs of white rectangular bars placed symmetrically about the centre line at 150 m intervals. They are required on paved precision approach runways with code number 2, 3 or 4. The number of pairs depends on LDA or, when both ends are marked, the distance between thresholds.
| LDA or distance between thresholds | Pairs |
|---|---|
| Less than 900 m | 1. |
| 900 m to less than 1,200 m | 2. |
| 1,200 m to less than 1,500 m | 3. |
| 1,500 m to less than 2,400 m | 4. |
| 2,400 m or more | 6. |
Taxiway centre lines and holding positions
Taxiway markings guide the nose wheel, then change form where an aircraft must stop to protect a runway, approach path or navigation-aid critical area.
Centre line and enhanced centre line
A taxiway centre line is a continuous yellow line at least 15 cm wide. It continues from runway centre line to the stand guidance system, curves smoothly through turns and is interrupted by runway-holding or intermediate-holding markings. Near a runway-holding position, an enhanced centre line adds dashed yellow lines on both sides of the normal centre line. It extends from Pattern A for up to 47 m in the direction away from the runway.
Pattern A
Pattern A has two solid and two broken yellow lines across the taxiway. Approaching the runway, the aircraft meets the solid lines and must not cross without the applicable clearance. It is used at a runway intersection for a non-instrument, non-precision or take-off runway and at a single holding position for a precision runway. When several positions exist, the closest to the runway is Pattern A.
Pattern B and intermediate holding
Pattern B is the ladder-style marking used for additional holding positions farther from a precision runway, including protection of category I, II or III critical and sensitive areas. An intermediate holding position at a taxiway intersection is a single broken yellow line, normally coincident with any stop bar or clearance bar.
| Marking | Where it is used | Pilot meaning |
|---|---|---|
| Pattern A | Visual runway-holding limit closest to runway. | Hold before the solid lines unless cleared to proceed. |
| Pattern B | Additional precision-runway or ILS-sensitive-area limit. | Hold when instructed or when its associated mandatory sign applies. |
| Intermediate | Taxiway intersection or specified intermediate point. | Hold at the single broken line when required. |
VOR checkpoint, stands, apron and roads
Special markings organise navigation checks, parking and the safe separation of aircraft from vehicles and equipment.
VOR aerodrome checkpoint
The checkpoint marking is a circle 6 m in diameter with a 15 cm line. If the aircraft must align on a specified azimuth, a 15 cm line passes through the circle and extends 6 m beyond it in the required heading, ending in an arrow. It is preferably white and must differ from taxiway-marking colour.
Aircraft stand markings
A stand system may include stand identification, lead-in line, turn bar, turning line, alignment bar, stop line and lead-out line. The identification is positioned soon after the start of the lead-in. Lead-in, turning and lead-out lines are continuous and at least 15 cm wide. Where several aircraft layouts overlap, the most demanding type normally receives continuous lines while other layouts use broken lines.
Apron safety lines
Wingtip-clearance and service-road boundary lines define areas for ground vehicles and equipment and keep them separated from aircraft. They are continuous and at least 10 cm wide. Bali states that apron safety lines are red in India.
Isolated aircraft and road holding
An isolated parking position should be as far as practicable from other stands, buildings and public areas and never less than 100 m. A road-holding marking is placed across every road entrance to a runway and follows local road-traffic regulation. Where a mandatory sign cannot practicably be installed, a surface mandatory-instruction marking is used.
Mandatory and information signs
A sign's colour tells the pilot whether it is an instruction, a location statement or routing information before the inscription is read.
| Sign or marking | Colour rule | Meaning |
|---|---|---|
| Mandatory instruction sign | White inscription on red | A limit beyond which an aircraft or vehicle must not proceed without authority. Includes runway designations, category holding positions and NO ENTRY. |
| Location sign | Yellow inscription on black, with yellow border when alone | Identifies the taxiway, runway or pavement presently occupied. |
| Direction, destination or runway-exit sign | Black inscription and arrow on yellow | Shows routing or the direction to a named destination or exit. |
| Runway-vacated sign | Pattern A symbol on yellow | Shows the point beyond which the aircraft is clear of the runway and associated critical area. |
| Mandatory surface marking | White inscription on red | Replaces a mandatory sign when sign installation is impracticable. |
| Information surface marking | Yellow for location; black for direction or destination, with contrasting background where needed | Replaces or supplements an information sign. |
Placement and combination
A mandatory runway-designation sign is at least on the left of the taxiway facing the approach to the runway, and preferably on both sides. Category holding signs are on both sides facing the approach to the critical area. A NO ENTRY sign is at the start of the prohibited area. At a combination sign, left-turn directions sit left of the black location panel and right-turn directions sit to its right.
Construction and night use
Signs are frangible, rectangular with the long side horizontal, and low enough to preserve propeller and engine clearance. Red is reserved for mandatory instruction signs. Signs are reflective or illuminated for night use and illuminated in RVR below 800 m, at night with instrument runways, and at night with code 3 or 4 non-instrument runways.
Runway-incursion reading habit
- Identify the current taxiway from the black location sign.
- Read yellow direction panels outward from that location panel.
- Treat every red panel as a limit requiring authority.
- Match the sign with its pavement marking before crossing.