Airport Coordination Limited (ACL) is responsible for slot allocation, schedules facilitation and schedule data collection at a large number of varied airports and, in addition, provides a wide range of services to the aviation industry.
Slot allocation is a widely-recognised technique designed to balance the supply and demand for scarce airport capacity, in order to avoid unnecessary congestion and delays, through the issue of permissions for aircraft to land and take off at particular times.
Today ACL provides coordination services at all of the major airports in the UK and Ireland including Heathrow, Gatwick, Manchester, Stansted, Birmingham, Glasgow, Edinburgh, Aberdeen, London Luton, London City, Liverpool, Leeds Bradford, East Midlands, Doncaster Sheffield, Durham Tees Valley, Newcastle, Bristol, Cardiff, Southampton, Jersey, Bournemouth, Dublin, Shannon, Cork, Belfast International and Belfast City.
ACL also provides coordination services at Dubai International Airport, as well as Lagos and Abuja airports in Nigeria.
ACL has developed and implemented an internet-based self-service schedule coordination system for its airline and General/Business aviation customers called the Online Coordination System (OCS). 
