Taxiway Markings
Since airports have runways and taxiways and both serve very different purposes, in order to clearly differentiate between the two, runways are named using numbers and marked in white whereas taxiways are named using letters and marked in yellow. Taxiways may have a surface-painted centreline that consists of a continuous stripe. Taxiway edge markings are used to delineate the edge of the taxiway and are sometimes complemented with shoulder markings that mark areas in which the pavement is not designed to support the weight of an aircraft.
Holding Position Markings
These markings indicate where aircraft must stop when approaching a runway. They consist of four yellow lines, two solid and two dashed, spaced six or twelve inches apart, and extending across the width of the taxiway or runway.
Supplemental Holding Position Markings
These markings consist of a ladder-type pattern and are strategically located further away from the runway threshold to minimize the risk of interference with the ILS, this protected area is known as the ILS critical area. Pilots do not have to hold short of this marking unless specifically instructed by ATC to do so.
Enhanced Centreline Markings
To coincide with runway-holding position markings, larger airports may additionally use an enhanced taxiway centerline which consists of parallel dashed lines painted on both sides of the centreline and extends up to 150 feet prior to a runway. This warns the pilot that they are approaching a runway holding position marking and may need to stop.
Closed Taxiway Markings
Closed taxiways are marked using a yellow ‘X’ which are placed at each end of the closed portion.
Summary
References
- TP 312 – Aerodromes Standards and Recommended Practices
- AIM AGA 5.0 Markers, Markings, Signs and Indicators