A-CDM (Airport Collaborative Decision Making) — Airport Collaborative Decision Making

What A-CDM Is

Airport Collaborative Decision Making (A-CDM) is a concept developed by Eurocontrol to improve the efficiency and predictability of airport operations. Instead of each stakeholder tracking a flight's progress separately, A-CDM has them share a single, common set of real-time data about each aircraft's turnaround, so decisions are made jointly rather than in isolation.

The Partners

Core Concept Elements

A-CDM works by tracking a flight through a set of shared milestones during turnaround and pre-departure, replacing informal estimates with agreed, continuously updated times. Central to this is the Target Off-Block Time (TOBT) — the time the aircraft operator or ground handler expects the aircraft to be ready to leave the stand — which ATC uses to calculate a Target Start-up Approval Time (TSAT) for engine start and pushback. Variable taxi times, based on actual airport conditions rather than fixed averages, further refine the predicted runway sequence.

Why It Matters

Before A-CDM, each stakeholder often worked from its own estimate of when a flight would be ready, leading to mismatched expectations, unnecessary queuing at the runway, and wasted fuel and time. By giving everyone the same live picture of each aircraft's status, A-CDM allows:

Adoption

A-CDM has been implemented at a substantial number of major and regional airports across Europe, each following the common Eurocontrol specification while adapting procedures to local conditions, and similar collaborative-decision-making concepts have since been explored at airports outside Europe as well.