The capacity of Air Traffic Service (ATS) systems is shaped by route configuration, aircraft navigational accuracy, weather conditions, and controller workload. Ensuring safety, requires that the number of aircraft receiving Air Traffic Control (ATC) services does not exceed what can be safely managed under current operational conditions. ATS authorities are responsible for assessing and declaring ATC capacity for control areas, sectors, and aerodromes.
To strengthen States’ capabilities in airport and airspace capacity assessment—which is essential for effective Air Traffic Flow Management (ATFM) and Airport Collaborative Decision Making (A-CDM)—the ICAO APAC Airport and Airspace Capacity Assessment Workshop was held from 2 to 5 June 2025 in Yogyakarta, Indonesia. Hosted by AirNav Indonesia, the event welcomed 87 participants from 14 States/Administrations and four international organizations.
The Workshop featured collaboration with experts from FAA and EUROCONTROL, offering participants practical skills and global best practices. Various capacity assessment models were explored. Strategies to enhance capacity, such as reducing runway occupancy time and balancing arrival/departure flows, were discussed using real-world case studies.
Participants also gained insights into strategic and operational capacity assessments, integration of A-CDM into ATFM, and airspace optimization techniques like Flexible Use of Airspace (FUA), Free Route Airspace (FRA), Performance-Based Navigation (PBN), and sectorization. Human factors were emphasized, with a focus on starting with simple models and refining them with data.
As a key outcome, States/Administrations are now better equipped to assess and manage airspace capacity, supporting safer and more efficient traffic flow. ICAO’s Asia/Pacific Regional Office also initiated a draft regional guidance document to assist service providers in conducting capacity assessments, with endorsement expected at the APAC ATFM Steering Group Meeting in 2026.
