Displaced threshold
Encyclopedia
A displaced threshold is a runway
threshold located at a point other than the physical beginning or end of the runway. The portion of the runway so displaced may be used for takeoff
but not for landing
. Landing aircraft
may use the displaced area on the opposite end for roll out.
Most often the offset threshold is in place to give arriving aircraft clearance over an obstruction while still allowing departing aircraft the maximum amount of runway available. A displaced threshold may also be introduced if a beginning section of the runway is no longer able to sustain the continuous impact from landing aircraft. In such a case, aircraft are expected to land beyond the displaced threshold. Departing aircraft are permitted to use the displaced section of the runway for takeoffs or landing rollouts because those aircraft are not impacting the runway with the force of a landing aircraft.
Displaced thresholds have arrows as the center line of the runway. A thick white line with usually four arrows pointing in the direction of the runway denotes the end of the threshold and the beginning of the runway.
Thresholds are counted as part of the runway, and are included in the runway size. When viewing a runway's size with displaced thresholds, one must find out how long the displaced thresholds are in order to calculate the available landing distance.
Runway
According to ICAO a runway is a "defined rectangular area on a land aerodrome prepared for the landing and take-off of aircraft." Runways may be a man-made surface or a natural surface .- Orientation and dimensions :Runways are named by a number between 01 and 36, which is generally one tenth...
threshold located at a point other than the physical beginning or end of the runway. The portion of the runway so displaced may be used for takeoff
Takeoff
Takeoff is the phase of flight in which an aerospace vehicle goes from the ground to flying in the air.For horizontal takeoff aircraft this usually involves starting with a transition from moving along the ground on a runway. For balloons, helicopters and some specialized fixed-wing aircraft , no...
but not for landing
Landing
thumb|A [[Mute Swan]] alighting. Note the ruffled feathers on top of the wings indicate that the swan is flying at the [[Stall |stall]]ing speed...
. Landing aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...
may use the displaced area on the opposite end for roll out.
Most often the offset threshold is in place to give arriving aircraft clearance over an obstruction while still allowing departing aircraft the maximum amount of runway available. A displaced threshold may also be introduced if a beginning section of the runway is no longer able to sustain the continuous impact from landing aircraft. In such a case, aircraft are expected to land beyond the displaced threshold. Departing aircraft are permitted to use the displaced section of the runway for takeoffs or landing rollouts because those aircraft are not impacting the runway with the force of a landing aircraft.
Displaced thresholds have arrows as the center line of the runway. A thick white line with usually four arrows pointing in the direction of the runway denotes the end of the threshold and the beginning of the runway.
Thresholds are counted as part of the runway, and are included in the runway size. When viewing a runway's size with displaced thresholds, one must find out how long the displaced thresholds are in order to calculate the available landing distance.