Aerodromes: Lighting and Services

An approach lighting system extends the runway centre-line picture into the approach. Greater operating precision needs a longer, denser and more redundant pattern.

Simple approach lighting

A simple system has a row of lights on the extended centre line, extending whenever practicable for at least 420 m from the threshold, with a crossbar at 300 m. The crossbar is centred on and at right angles to the centre line. Its lights are spaced to create a linear effect. The system supports non-instrument and non-precision operations where the runway needs positive approach guidance.

Precision category I

A precision category I system extends 900 m from the threshold. In the Calvert pattern, five crossbars are spaced 150 m apart. The inner section reaches 300 m, the middle section 600 m and the outer section 900 m. An ICAO barrette pattern may use centre-line barrettes with a crossbar at 300 m. Sequenced flashing lights may supplement the steady lights and run toward the threshold.

Precision category II and III

The centre-line system also extends 900 m. The inner 300 m is strengthened by white centre-line barrettes and red side-row barrettes. Beyond 300 m, the pattern continues as the category I arrangement. The denser inner pattern provides roll and height cues when the runway environment becomes visible very late.

PAPI converts the aircraft's vertical angle into an immediate red-and-white display. It guides the approach path but does not replace obstacle clearance, altimetry or a published instrument procedure.

Four light units

A PAPI has four wing-bar units, normally on the left of the runway. Each unit appears white above its transition angle and red below it. The units have slightly different transition angles, so the combined pattern shows the aircraft's position relative to the nominal glide path. The nominal on-slope path is usually about 3 degrees.

APAPI and eye-height protection

An abbreviated PAPI has two units. Two white means above, one white and one red means on slope, and two red means below. The siting angle must provide adequate wheel clearance over the threshold. The minimum eye height over threshold, called MEHT, is published so the operator can check compatibility with the aircraft's eye-to-wheel geometry.

Runway lights identify the usable landing rectangle, its beginning and end, its centre line, and the distance remaining in the final part of a low-visibility landing roll.

Displaced threshold lighting

Where a threshold is displaced, runway-edge lights before the threshold show red in the approach direction. Threshold lights and wing bars are placed at the displaced threshold and show green toward the approach. The pavement before the threshold may still be available for take-off or for landing rollout from the opposite direction, but it is not the beginning of LDA in the displaced direction.

Taxiway lights guide movement without being mistaken for runway lights. Red systems protect a runway entry, while yellow systems draw attention to a holding point or guard a runway.

Stop bars in low visibility

Bali requires a stop bar at every runway-holding position serving a runway intended for use when RVR is below 350 m, except where other appropriate aids or procedures provide equivalent protection. A clearance does not cancel a lit red stop bar. The stop bar must first be extinguished under the operating procedure.

Runway turn pads and lead-on lights

Runway turn-pad lights are fixed unidirectional green and guide an aircraft through a turn of 180 degrees before aligning with the runway centre line. Where the taxiway centre line leads onto a runway, the lighting provides continuous guidance but must preserve the runway's distinct visual identity.

Obstacle limitation surfaces protect volumes of airspace around the runway. They control the height and location of objects so take-off, approach and circuit operations retain predictable margins.

Obstacle identification surface

Bali describes an obstacle identification surface extending to 15 km. It begins at the cleared strip, rises through an inner transition to 45 m, and then through an outer transition to 150 m. Obstacles that penetrate the applicable surface are surveyed, assessed and published. Marking or lighting makes an obstacle conspicuous but does not remove any operating limitation that the obstacle creates.

An obstacle should be conspicuous by day and identifiable at night. The system chosen depends on its size, mobility, background and height.

Day marking

Fixed objects are coloured where practicable. A chequered pattern uses orange and white or red and white where an object has substantial surfaces. Bands are used for long, narrow or skeletal objects. Flags or markers may be used where painting is impracticable. Overhead wires and cables are marked by conspicuous spheres. Mobile objects normally use one conspicuous colour, preferably red or yellowish green for emergency vehicles and yellow for service vehicles.

Closed and unserviceable areas

A closed runway carries white X markings at each end and at intervals not exceeding 300 m. A closed taxiway carries yellow X markings at least at each end. Normal lighting is not operated on a closed portion except for maintenance. Where paved pre-threshold pavement exceeds 60 m and is unsuitable for normal aircraft use, yellow chevrons point toward the runway. Unserviceable portions are marked by boards, cones, flags or lights, with fixed red unserviceability lights used at night.

The rescue and fire fighting category is driven first by the longest aeroplane normally using the aerodrome, then checked against fuselage width. The objective is to save lives by reaching a survivable accident quickly and controlling the fire.

Selecting the category

1. Find the category for the aeroplane's overall length.
2. Compare its maximum fuselage width with that category's limit.
3. If the fuselage is wider, use the next higher category.

Where movements by aeroplanes in the highest category are fewer than 700 during the busiest consecutive three months, the protection may be one category lower. During a planned period of reduced activity, protection must still match the highest category of aeroplane planned to operate in that period.

Extinguishing agents

The principal agent is foam meeting the required performance level. A complementary agent, normally dry chemical powder suitable for hydrocarbon fires, provides rapid knockdown. The following commonly examined minimum quantities show water for foam of performance level B and complementary dry chemical powder.

Equipment quantity is only one part of protection. Trained crews, alerting, direct access, command arrangements and recovery planning determine whether resources reach the accident in time.

Response time and access

Bali states an operational objective not exceeding 3 minutes to any point of each operational runway in optimum visibility and surface conditions, with an objective of not more than 2 minutes. Response time runs from the initial call until the first vehicle is in position to apply foam at at least 50 per cent of the specified discharge rate. Emergency access roads should support this objective, particularly in approach areas up to 1,000 m from the threshold or at least to the aerodrome boundary.

Fire stations and communications

RFF vehicles are normally housed in a fire station. Satellite stations are provided when one location cannot meet the response objective. Access to the runway should be direct and clear with few turns. A discrete communication system links the fire station, control tower, vehicles and relevant emergency agencies, supported by an alerting system for RFF personnel.

Aerodrome emergency plan

The plan coordinates action for aircraft accidents, fires, sabotage, unlawful seizure, bomb threats, dangerous-goods events, public-health emergencies and natural disasters. It identifies command, an emergency operations centre, a mobile command post, agency responsibilities, communication methods, grid maps, rendezvous points, medical and transport resources, and arrangements beyond the aerodrome boundary. Exercises test whether the plan works. A full-scale exercise is held at intervals not exceeding two years with a partial exercise in the intervening year, or a modular series is completed within a cycle not exceeding three years. The plan is reviewed after exercises and real emergencies.

Disabled aircraft removal

An aerodrome has a plan for removing an aircraft disabled on or near the movement area. It identifies the coordinator, available lifting and towing equipment, routes, communications and access to aircraft-recovery data. The aircraft operator or owner retains responsibility for removal, while the aerodrome coordinates safety and restoration of operations. The plan must consider the largest type that the aerodrome regularly expects to handle.

The apron combines moving aircraft, vehicles, people, fuel and ground equipment. Safe operation depends on coordinated movement, clean surfaces, wildlife control and an immediate route to emergency help.

Apron management service

Where traffic volume and operating conditions warrant it, apron management may be provided by ATS, the aerodrome operator or a cooperative combination. It is not the same as aerodrome Ground Control. Procedures provide an orderly transfer between the apron unit and the control tower.

1. Regulate movement to prevent collision between aircraft and between aircraft and obstacles.
2. Coordinate entry to and exit from the apron with the control tower.
3. Ensure safe and expeditious vehicle movement and regulate other apron activities.

The service requires radiotelephony. During low-visibility procedures, people and vehicles on the apron are restricted to the essential minimum. Stands are monitored so recommended clearances are preserved. Emergency vehicles have priority. Other vehicles give way to an emergency vehicle and to an aircraft taxiing, about to taxi, being pushed or being towed.

Ground servicing and fuelling

Suitable fire-extinguishing equipment and trained personnel must be readily available during ground servicing, with a quick means of summoning RFF for a fire or major fuel spill. If passengers are embarking, on board or disembarking during refuelling, ground equipment must leave enough exits available and a ready escape route from every exit intended for emergency use.

Wildlife hazard management

The aerodrome records and reports wildlife strikes, assesses the hazard created by birds and other animals, and reduces it through habitat management, active dispersal and coordination over land use near the aerodrome. Food waste, standing water, vegetation and poorly managed disposal sites can attract wildlife. Control measures must be systematic and must not create a new aviation hazard.

Foreign-object debris

FOD includes loose stones, tools, metal, baggage parts and other material that can damage aircraft, engines or tyres. Scheduled inspections, prompt removal, secure equipment and reporting of debris are core movement-area duties. Construction and maintenance require heightened inspection and positive control of loose material.