Land and hold short operations

"Lahso" redirects here. For a Thai footballer, see Adul Lahso.

Land and Hold Short Operations (LAHSO, pronounced "La-So") is an air traffic control procedure for aircraft landing and holding short of an intersecting runway or point on a runway, to balance airport capacity and system efficiency with safety.

Its use is voluntary: if a pilot denies LAHSO clearance the Air Traffic Controller must revector the aircraft to ensure adequate separation from other aircraft landing or departing an intersecting runway or crossing down field. A heightened level of situational awareness is necessary, and student pilots or pilots not familiar with LAHSO should not participate in the program.

Although used in the US, many countries do not permit LAHSO clearances, and some airlines' operating procedures do not allow their acceptance in countries that do permit them.

LAHSO was previously called SOIR (Simultaneous Operations on Intersecting Runways), and incorporates and expands all SOIR definitions.

Types

There are three main types, to land and hold on the runway:

• Intersecting Runway: before the intersection with another runway that will have another aircraft taking off or landing.
• Intersecting Taxiway: before the intersection with a taxiway that will have other aircraft taxiing for takeoff or parking.
• Point on Runway: before a designated point. This is the newest type, used when safety precautions are needed due to hazards concerning other runways or taxiways, or hazards for a landing plane on its runway (ice, for instance).

Requirements

Pilots should receive a LAHSO clearance only when there is a minimum ceiling of 1,000 feet and 3 statute miles visibility, to allow them to maintain visual contact with other aircraft and ground vehicle operations.

References

Other sources

• Aircraft Owners and Pilots Association
• Federal Aviation Administration
• Aeronautical Information Manual 4-3-11: Pilot Responsibilities When Conducting Land and Hold Short Operations (LAHSO)
• FAA LAHSO guide: https://www.faasafety.gov/files/gslac/courses/content/25/181/LAHSO.pdf