Have you ever given any thought to the road line marking on runways? Most of us hop on and off planes every year, so you would think that we would know everything there is to know about airports, but runway markings?
When you are taxiing for take off or to the terminal, have you ever looked at the road line marking on the runways and wondered what they actually mean? Clearly they are meant to direct planes and should be universally interpreted by all airline pilots, regardless of nationality, but what do they actually mean to the pilots?
Well, let’s look at three different types of road line marking: pre-runway end markings, runway centreline markings, and runway designation markings.
What are pre-runway end markings?
Pre-runway end markings are yellow chevrons spaced 30 m apart and angled at 45 degrees to the runway centreline. They alert pilots to the existence of an area at the end of the runway that is not suitable for normal usage by aircrafts.
These yellow chevron road line markings are placed where a sealed, concrete or asphalt surface exists at the end of the runway, warning pilots when they are at least 60 m away from this safety hazard and ending when the hazard has been reached. This area must not be used by any aircraft, except when it has been designated as a stopway, when aircrafts that have abandoned their take-off in the other direction, may access it in an emergency.
What are runway centreline markings?
On all sealed, concrete or asphalt runways (except runways that are 18 m wide and have side strip markings) there are centreline markings that provide directional guidance to pilots during take-off and landing. The runway centreline must start 12 m from the runway designation marking and the width of these lines will differ depending on whether it is a non-instrument runway (width must be 0.3 m), an instrument non-precision runway (width must be 0.45 m) or a category II or III precision approach runway (width must be 0.9 m).
The centreline runway road line marking, which consists of the line itself and the uniform gap between the markings must be at least 50 m in length (line marking + gap), but not more than 75 m. The length of each centreline stripe must also be at least equal to the size of the uniform gap or be 30 m in length, whichever is greater.
What are runway designation markings?
You might have noticed the large two digit numbers at the end of runways? These are the runway designation markings and indicate the correct runway for pilots when they are coming in to land. The numbers are actually the magnetic compass bearings of the runway’s centreline that would be seen by pilots on their approach and rounded to the nearest 10 degrees; single bearings are preceded by a zero to make them into two digit numbers.
If two or more runways lie in parallel (so they would have the same designation markings) they are distinguished by having the letters R (right), L (left) or C (centre) at the end of the number and the length of these markings must be 9 m. If there is any confusion between these road line markings at the same airport or between different airports, then the Civil Aviation Safety Authority (CASA) will make the final decisions.