Anticipated Separation: Departure / Departure

Takeoff clearance needs not be withheld until prescribed separation exists if there is a reasonable assurance it will exist when the aircraft starts takeoff roll.

The first aircraft must be airborne before the second aircraft commences the take-off roll (in addition, aircraft type should be taken into account).

For example, if aircraft A (B737) is above 100knts GS and aircraft B (A320) is holding short, simply clear aircraft B for takeoff. No need for a line up and wait instruction.

Runway Touchdown Zone Marking

The touchdown zone markings identify the touchdown zone for landing operations and are coded to provide distance information in 500 feet (150m) increments. These markings consist of groups of one, two, and three rectangular bars symmetrically arranged in pairs about the runway centerline. For runways having touchdown zone markings on both ends, those pairs of markings which extend to within 900 feet (270m) of the midpoint between the thresholds are eliminated.

Source: FAA

Runway Threshold Markings

Runway threshold markings come in two configurations. They either consist of eight longitudinal stripes of uniform dimensions disposed symmetrically about the runway centerline, or the number of stripes is related to the runway width as indicated. A threshold marking helps identify the beginning of the runway that is available for landing. In some instances the landing threshold may be relocated or displaced.

Source: FAA

Visual Runway Markings

Visual runways are used at small airstrips and are usually just a strip of grass, gravel, ice, asphalt, or concrete. Although there are usually no markings on a visual runway, they may have threshold markings, designators, and centerlines. Additionally, in the real world, they do not provide an instrument-based landing procedure; pilots must be able to see the runway to use it.

Picture Source: FAA

Runway Markings

There are runway markings and signs on most large runways. Larger runways have a distance remaining sign (black box with white numbers). This sign uses a single number to indicate the remaining distance of the runway in thousands of feet. For example, a 7 will indicate 7,000 ft (2,134 m) remaining. The runway threshold is marked by a line of green lights.