A displaced threshold or DTHR is a runway threshold located at a point other than the physical beginning or end of the

runway In aviation, a runway is an elongated, rectangular surface designed for the landing and takeoff of an aircraft. Runways may be a human-made surface (often asphalt concrete, asphalt, concrete, or a mixture of both) or a natural surface (sod, ...

. The portion of the runway behind a displaced threshold may be used for

takeoff Takeoff is the phase of flight in which an aerospace vehicle leaves the ground and becomes airborne. For aircraft traveling vertically, this is known as liftoff. For aircraft that take off horizontally, this usually involves starting with a tr ...

in either direction and

landing Landing is the last part of a flight, where a flying animal, aircraft, or spacecraft returns to the ground. When the flying object returns to water, the process is called alighting, although it is commonly called "landing", "touchdown" or " spl ...

s from the opposite direction. After landing at the other end, the landing

aircraft An aircraft ( aircraft) is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or the Lift (force), dynamic lift of an airfoil, or, i ...

may use the area behind the displaced threshold for roll out.Aircraft Information Manual 2013, Chapter 2-3-3 h (2) Section 3. Airport Marking Aids and Signs

/ref> 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 as a noise mitigation measure for the communities overflown on approach, or if a beginning section of the runway is no longer able to sustain the continuous impact from landing aircraft. Aircraft are expected to land beyond the displaced threshold. Departing aircraft are permitted to use the section of the runway behind a displaced threshold for takeoffs or landing rollouts from the opposite direction even if the reason for the displacement is lowered pavement resistance, because those aircraft are not impacting the runway with the force of a landing aircraft. A portion of the runway behind a displaced threshold has three markings: * White arrows along the center line of the runway * White arrow heads across the width of the runway just prior to the displaced threshold bar * A wide white threshold bar across the width of the runway at the displaced threshold Runway 29L at Indira Gandhi International Airport, in

Delhi Delhi, officially the National Capital Territory (NCT) of Delhi, is a city and a union territory of India containing New Delhi, the capital of India. Straddling the Yamuna river, but spread chiefly to the west, or beyond its Bank (geography ...

, India, has a displaced threshold of from the physical beginning of the pavement. This produces a portion of runway that cannot be used for landing in this direction. This, in turn decreases the available landing length on runway 29L to . This is because aircraft coming in to land need to avoid the

Shiva Shiva (; , ), also known as Mahadeva (; , , Help:IPA/Sanskrit, ɐɦaːd̪eːʋɐh and Hara, is one of the Hindu deities, principal deities of Hinduism. He is the God in Hinduism, Supreme Being in Shaivism, one of the major traditions w ...

statue, which is located near runway 29L. Runway 22R at

John F. Kennedy International Airport John F. Kennedy International Airport is a major international airport serving New York City and its metropolitan area. JFK Airport is located on the southwestern shore of Long Island, in Queens, New York City, bordering Jamaica Bay. It is ...

has a displaced threshold due to noise abatement. This shortens the landing distance available to just for the runway.

References

Airport infrastructure {{aviation-stub