AERODROME TRAINING COURSEModule 3 Aerodrome Physical Characteristics

LEARNING OUTCOME

Participants will gain an overview of the required physical characteristics for aerodromes including:

Application aerodrome reference code Runways Taxiways ApronsWith the access to reference documents they

will be able to determine the physical characteristics required for specific aircraft types.

AERODROME REFERENCE CODE

Provides a simple method for interrelating the numerous specifications concerning the characteristics of aerodromes to ensure they are suitable for aeroplanes that are intended to operate at the aerodrome.

Consists of 2 elements Code number element 1 corresponding to aeroplane

reference field length(Definition -Aeroplane reference field length. The minimum field length

required for take-off at maximum certificated take-off mass, sea level, standard atmospheric conditions, still air and zero runway slope, as shown in the appropriate aeroplane flight manual prescribed by the certificating authority or equivalent data from the aeroplane manufacturer. Field length means balanced field length for aeroplanes, if applicable, or take-off distance in other cases.)

Code Letter element 2 corresponds to the wing span or the outer main gear wheel span, whichever is more demanding

AERODROME REFERENCE CODE

RUNWAYS

Location and Orientation Type of intended operation (non-instrument or

instrument) Need to ensure that the required take-off and

approach obstacle limitation surfaces are not infringed

Environmental impact – minimize noise on residential areas

Prevailing winds – 20kts max x-wind component for runways 1500m and over

Usability factor of the aerodrome to be not less than 95% for aeroplanes that the aerodrome is intended to serve

RUNWAYS

Length - Adequate to meet operational requirements of the aeroplanes for which the runway is intended

Width -

RUNWAYS – PARALLEL OPERATIONS

Minimum Separation Distance Non-instrument – 210m Code 3 & 4, 150m Code 2,

120m code 1

Instrument – 1035m independent parallel approaches915m dependent parallel approaches760m independent parallel departures760m segregated parallel operations

PANS OPS and PANS ATM additional Requirements

1035m-1310m SSR 2.5sec update 0.06° accuracy1310m-1525m SSR 5sec update 0.3° accuracy1525m≤ radar (PRIM or SSR) 5 sec/3°

RUNWAY SLOPES - LONGITUDINAL The slope computed by dividing the difference between

the maximum and minimum elevation along the runway centre line by the runway length should not exceed:— 1 per cent where the code number is 3 or 4; and— 2 per cent where the code number is 1 or 2.

Along no portion of a runway should the longitudinal slope exceed:— 1.25 per cent where the code number is 4, except that for the first and last quarter of the length of the runway the longitudinal slope should not exceed 0.8 per cent;— 1.5 per cent where the code number is 3, except that for the first and last quarter of the length of a precision approach runway category II or III the longitudinal slope should not exceed 0.8 per cent; and— 2 per cent where the code number is 1 or 2.

RUNWAYS – SIGHT DISTANCES Where slope changes cannot be avoided, they should

be such that there will be an unobstructed line of sight from:— any point 3 m above a runway to all other points 3 m above the runway within a distance of at least half the length of the runway where the code letter is C, D, E or F;— any point 2 m above a runway to all other points 2 m above the runway within a distance of at least half the length of the runway where the code letter is B; and— any point 1.5 m above a runway to all other points 1.5 m above the runway within a distance of at least half the length of the runway where the code letter is A.

RUNWAYS SLOPES - TRANSVERSE

To promote the most rapid drainage of water, the runway surface should, if practicable, be cambered except where a single crossfall from high to low in the direction of the wind most frequently associated with rain would ensure rapid drainage. The transverse slope should ideally be:— 1.5 per cent where the code letter is C, D, E or F; and— 2 per cent where the code letter is A or B;

but in any event should not exceed 1.5 per cent or 2 per cent, as applicable, nor be less than 1 per cent except at runway or taxiway intersections where flatter slopes may be necessary.

For a cambered surface the transverse slope on each side of the centre line should be symmetrical

RUNWAYS - SURFACE

Design objectives Constructed without irregularities that would

adversely affect take-off or landings or loss of friction

Constructed to provide good friction characteristics when runway is wet

Surface texture depth should not be less than 1.0mm

Maintenance objectives Kept clear of loose objects (FOD) Prevent formation of harmful irregularities Friction testing and corrective action to remain

above minimum friction level

RUNWAY – PAVEMENT TYPES

Flexible

Rigid

RUNWAY/PAVEMENT STRENGTH ACN- Aircraft Classification Number (Number expressing

the relative effect of an aircraft on a pavement for a specified standard subgrade strength)

PCN – Pavement Classification Number (Number expressing the bearing strength of a pavement for unrestricted operations)

ACN/PCN meant as means for publishing pavement strength in AIP it is not a design or an evaluation tool

Requires reporting of• Pavement type R or F• Subgrade category• Maximum tyre pressure• Pavement evaluation method

ACN - PCN

RUNWAYS - SHOULDERS

Provided – when code is D or E and runway width less than 60m when code is F

Width – extend symmetrically each side so that overall width of runway and shoulders is – 60m Code D or E; 75m code F

Slope – flush with surface it abuts and not to exceed 2.5% transverse

Strength – capable of supporting aeroplane without inducing structural damage and supporting ground vehicles

RUNWAYS TURN PADS

Required for code D, E, F where end of runway not served by taxiway to facilitate 180° turns.

May be located on either side but left preferable

Intersection angle with runway should not exceed 30°

RUNWAY STRIPS A defined area including the runway and stopway, if provided,

intended:

a) To reduce the risk of damage to aircraft running off the runway

b) To protect aircraft flying over it during take-off or landing operations

Graded portion in event of an aeroplane running off the runway

Width graded portion – extend 75m either side centreline Code 3, 4

- extend 40m either side centreline Code 1, 2

Surface graded portion - flush with runway or shoulder

- longitudinal slope 1.5% code 4, 1.75% code 3

- transverse slope 2.5% code 3,4 (5% 1st 3m drainage)

- strength to minimize hazards in event aircraft running off runway

Objects – shall satisfy the relevant frangibility requirement in chapter 5 Annex 14 volume 1.

RUNWAY STRIPS Length - Strip shall extend before the threshold and

beyond the end of the runway or stopway for a distance 60m code 2,3,4,

Width –

-Instrument Code 3 & 4 = 150m (either side centreline)

- Instrument Code 1, 2 = 75m

- Non-instrument Code 3 & 4 =75m

- Non-instrument code 2 = 40m

- Non-instrument code 1 = 30m

RUNWAY END SAFETY AREAS Length – Shall extend 90m from end of runway strip

- Should extend as far as practicable and at least 240m

Width – At least twice that of the runway - Should wherever practicable be equal to graded

portion

Slopes – Longitudinal below OLS & max 5% downward - Transverse 5%

Surface – clear graded,

Strength – reduce the risk of damage to aircraft and facilitate movement RFFS vehicles

CLEARWAYS

Only need to be provided where operating advantage is required by aircraft using unbalanced performance –TODA greater than TORA

Length – Should not exceed half the length of TORA

Width – 75m either side of centreline

Slope – not to exceed 1.25% upwards

STOPWAYS

Only need to be provided where operating advantage is required by aircraft using unbalanced performance –ASDA greater than TORA

Width – Same width as runway

Slopes – Same as for runway

Strength – supporting aircraft without inducing structural damage to the aircraft

Surface – Coefficient of friction to be compatible with runway

TAXIWAYS

Design to ensure critical aeroplane when remaining over centrelinemarkings that the following outer main wheel clearances achieved

Code A B C D E F

Clearance 1.5m 2.25m 3m* 4.5m 4.5m 4.5m

TAXIWAYS - FILLETS

TAXIWAYS - WIDTH

Code A B C D E F

Width 7.5m 10.5m 15m* 18m** 23m 25m

*18m if wheel base greater than 18m**23 if outer main gear wheel span greater than 9m

Curves/IntersectionsNeed to implement fillets based on critical aircraft

TAXIWAYS – SEPARATION DISTANCES

TAXIWAYS – RAPID EXIT Turn-off curve radius – Code 3 & 4 550m (exit speed

93kph/50kts) Code 1 & 2 275m (exit speed 65kph/35kts)

Intersection angle – optimum 30°, max 45°, min 25° Straight distance – sufficient for aircraft to come to full

stop clear intersecting taxiway

TAXIWAYS

SLOPESLongitudinal – 1.5% code C, D, E, F; 3% code A, B.Sight Distance – code C, D, E, F 3m above taxiway see whole

surface for distance of at least 300mTransverse – 1.5% code C, D, E, F; 2% code A, B

ShouldersShould be provided each side for code C to F so overall width taxiway and shoulders

Code C D E F

Width 25m 38m 44m 60m

TAXIWAYS - STRIPS

Width – Extend symmetrically each side to achieve minimum distance from centreline as per table 3-1 column 11

Code A B C D E F

Semi-width 16.5m 21.5m 26m 40.5m 47.5m 57.5m

Graded Portion – Extend symmetrically each as below

Code A B C D E F

Semi-width 11m 12.5m 12.5m 19m 22m 30m

RUNWAY HOLDING POSITIONS

APRONS

Slopes – maximum 1% on aircraft stands

Clearances – between aircraft using stand and other aircraft building object or other aircraft

Code A B C D E F

Clearance 3m 3m 4.5m 7.5m* 7.5m* 7.5m*

*May be reduced in special circumstances between terminal and nose of aircraft and over any portion of stand provided with visual dockingguidance system

ISOLATED PARKING POSITION

An isolated aircraft parking position shall be designated or the aerodrome control tower shall be advised of an area or areas suitable for the parking of an aircraft which is known or believed to be the subject of unlawful interference, or which for other reasons needs isolation from normal aerodrome activities.

The isolated aircraft parking position should be located at the maximum distance practicable and in any case never less than 100 m from other parking positions, buildings or public areas, etc. Care should be taken to ensure that the position is not located over underground utilities such as gas and aviation fuel and, to the extent feasible, electrical or communication cables.

PRACTICAL EXERCISE

1. The minimum runway width for a Code 4C runway is?

2. The distance that a runway strip should extend beyond the end of a Code 2 runway is

3. A minimum length RESA for a Code 4 runway strip shall extend to at least (a) 90m, (b) 150m (c) 240m past the end of the runway?

4. Calculate the minimum distances between taxiway centrelines for a Taxiway handling Code D aircraft an a taxiway handling only Code A and B aircraft.