08 Aerodromes & Runways

How are TORA, TODA, ASDA and LDA related?

TORA = runway available for take-off ground run; TODA = TORA + clearway; ASDA = TORA + stopway; LDA = runway available for landing ground run.

What is the practical difference between a clearway and a stopway?

A clearway provides obstacle-free space for the airborne part of take-off and need not support the aircraft; a stopway is prepared to support an aircraft during a rejected take-off.

How does a displaced threshold affect declared distances?

It reduces LDA for approaches to that threshold; pavement before it may still be available for take-off and other operations as declared.

Why must an intersection departure be explicitly accounted for in performance?

Available TORA/TODA/ASDA are reduced from the selected intersection.

What is the purpose of a RESA?

To reduce the consequences of runway overruns and undershoots.

What are the key aerodrome light colours worth knowing?

Runway edge: white, becoming yellow near the far end; threshold: green; runway end: red; runway centreline: white → alternating red/white → red; taxiway centreline: green; taxiway edge: blue; stop bar: red; runway guard lights: yellow.

How do runway centreline lights change near the runway end?

White until 900 m remaining, alternating red/white from 900 to 300 m, then red for the final 300 m.

What does yellow runway edge lighting indicate?

The final 600 m or final one-third of the runway, whichever is less, viewed in the take-off direction.

How do you interpret a standard four-unit PAPI?

2 white/2 red = on slope; more white = high; more red = low.

Does following PAPI from any lateral position guarantee obstacle clearance?

No. Its obstacle protection is based on the designed approach geometry.

What is the key colour logic for aerodrome markings and signs?

Runway markings are white; taxiway markings are yellow; mandatory instruction signs use white text on red; location signs use yellow text on black; direction/destination signs use black text on yellow.

What does a standard runway-holding marking indicate?

The aircraft must remain on the holding side of the marking until cleared to proceed.

What does an illuminated stop bar mean?

STOP — do not cross.

Does an ATC clearance by itself authorise crossing an illuminated stop bar?

No. Under normal procedures, the stop bar must also be extinguished.

What is the purpose of runway guard lights?

To make a runway-holding position conspicuous and reduce runway-incursion risk.

What is a runway incursion versus a runway excursion?

Incursion = incorrect presence on the protected runway area; excursion = aircraft leaves the runway surface by veering off or overrunning.

What cockpit actions are particularly effective against runway incursions?

Taxi briefing, chart monitoring, explicit runway-crossing awareness, stop-bar discipline and independent verification of runway identity before take-off.

What should the crew do if position on the manoeuvring area becomes uncertain?

Stop and clarify the aircraft position before continuing.

What are useful ways to verify the correct runway before take-off?

Cross-check signs and markings, runway designation, aircraft heading/navigation display and airport chart.

Why are ILS critical/sensitive areas protected during low-visibility operations?

Aircraft or vehicles can disturb the transmitted guidance signal.

What is the practical difference between RVR and meteorological visibility?

RVR is runway-specific visibility of runway markings/lights from the centreline; meteorological visibility is a general atmospheric visibility measurement.

What is the purpose of the Global Reporting Format (GRF)?

To provide a standardised assessment of runway surface condition and its expected effect on aircraft performance.

How is runway condition expressed using RWYCC?

Three codes from 0 to 6, one for each runway third.

What do RWYCC values 6 to 0 broadly represent?

6 dry; 5 good; 4 good-to-medium; 3 medium; 2 medium-to-poor; 1 poor; 0 less-than-poor.

What is RCAM?

The Runway Condition Assessment Matrix linking surface contaminant type/depth and observations to an RWYCC and expected braking performance.

What is the important 25% coverage rule in GRF?

A runway is considered contaminated when more than 25% of at least one runway third is covered by relevant contamination.

What RWYCC is normally assigned when 25% or less of a runway third is wet or contaminated?

RWYCC 6, although the contaminant may still be reported as applicable.

What is the key 3 mm distinction for water and slush?

Up to 3 mm is treated in the wet/slush ≤3 mm category; more than 3 mm standing water or slush normally results in RWYCC 2.

What RWYCC is normally associated with a wet runway?

RWYCC 5.

What RWYCC is normally associated with slippery-wet conditions?

RWYCC 3.

What RWYCC is normally associated with untreated ice?

RWYCC 1.

What does RWYCC 0 mean operationally?

Less-than-poor braking; operations under such braking conditions are prohibited.

Can a pilot braking-action report affect the aerodrome-assigned RWYCC?

Yes. It may require downgrading; upgrading is permitted only under specific GRF conditions.

Can contaminant-based RWYCC 5, 4, 3 or 2 normally be upgraded?

No. RWYCC 1 or 0 may, under defined procedures, be upgraded to a maximum of 3.

Why must each runway third be considered separately?

Contamination and braking performance may vary significantly along the runway.

Why is touchdown position especially important on a wet or contaminated runway?

A long touchdown consumes stopping distance when braking capability may already be reduced.

Why is excess landing speed particularly costly on a contaminated runway?

Kinetic energy rises with speed squared while available tyre/runway friction may be reduced.

Why is standing water a take-off hazard in addition to reduced braking?

It adds displacement/impingement drag, increases hydroplaning risk and can produce spray-related effects.

Why should pilot braking reports from another aircraft be interpreted cautiously?

Braking performance depends on aircraft type, mass, tyres, speed, braking system and technique.