What is Runway Displaced Threshold
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 behind a displaced threshold may be used for takeoff in either direction and landings from the opposite direction.
Displaced thresholds are used for a variety of reasons, including:
- To shorten the runway available for landings in order to protect an object or area off the end of the runway, such as a taxiway, a runway safety area, or a populated area.
- To protect the runway surface from excessive wear and tear, such as from the repeated impact of landing aircraft.
- To mitigate noise pollution from aircraft landings.
Displaced thresholds are marked with a white line across the runway, with white arrows leading up to it. Pilots must be aware of the location of displaced thresholds and must not land before the displaced threshold.
![runway marks - What is Runway Displaced Threshold](https://www.aviationfile.com/wp-content/uploads/2021/04/runway-marks.jpg)
Here are some of the important things to know about displaced thresholds:
- The portion of the runway behind the displaced threshold is not available for landings in the direction of the displaced threshold.
- The displaced threshold is not a physical barrier, so aircraft can still cross it. However, pilots should avoid crossing the displaced threshold unless it is necessary to do so.
- Pilots must be aware of the displaced threshold when planning their approach. They should not land before the displaced threshold, even if they have enough runway remaining to do so.
- Displaced thresholds are marked on approach charts and in airport charts. Pilots should familiarize themselves with the location of displaced thresholds before flying into an airport.
![Airport Layout](https://www.aviationfile.com/wp-content/uploads/2020/08/Aerodrome-Layoout-1024x506.jpg)
References and Further Reading
- Federal Aviation Administration (FAA):
- Aeronautical Information Manual (AIM) PCG D-3: https://www.faa.gov/air_traffic/flight_info/aeronav/digital_products/dtpp/search/
- 5640.5A – Airport Marking and Lighting: https://www.faa.gov/airports/resources/advisory_circulars/index.cfm/go/document.current/documentnumber/150_5340-1
- International Civil Aviation Organization (ICAO):
- Annex 14 – Aerodromes: https://www.icao.int/APAC/Meetings/2015%20WAWG1/an14_1ed_1951.pdf
- Doc 9157 – Aerodrome Design Manual: https://store.icao.int/en/aerodrome-design-manual-runways-doc-9157-part-1
Further reading: https://www.aviationfile.com/what-is-turn-pad-on-runways/