Glossary & Definitions

Capacity – Airside – Runway

Airside Capacity

  • Amount of air traffic which an airport’s airside system comprising runways, taxiways and aircraft stands can accommodate per unit of time
  • Airside capacity is defined by the maximum capacity of the weakest element of the airside
  • CAST Aircraft simulation is widely used for the assessment of airside capacity

Airport Capacity

  • Amount of air traffic, passengers and vehicles which an airport system comprising airside, terminal and landside access can accommodate per unit of time
  • Airport capacity is defined by the maximum capacity of the weakest element of the airport
  • CAST Simulation suite with its Aircraft, Terminal and Vehicle modules can be deployed to determine the system capacity of the limiting element

With this glossary we would like to give short, basic explanations and definitions for important and frequently used terms in the fields of Analysis, Runway and Terminal Capacity Assessment and Airport Simulation/Allocation. These are based on our experience of practical application in the industry. We would be happy to provide you with more detailed definitions and further explanations. Please feel free to contact us.

Runway Capacity

  • Number of aircraft movements, which can be handled by a runway, final approach and SID system of an airport under defined conditions as structure of the traffic demand, operational concept, weather conditions and ATC rules
  • Can be determined as sustained/declared capacity or as maximum capacity

Airport Capacity Planning and Assessment

  • Comprises activities related to the capability of an airport system or it’s components to handle a certain demand in flight and passengers
  • Overall objective is the demand-oriented, balanced and sustainable use and development of infrastructure and operational procedures, taking into account economic, environmental and qualitative corporate objectives
  • Comprises the long term strategic planning and development of the infrastructure, the medium term and tactical adaptation and the short term optimisation of the airport system also considering operational concepts, procedures and supporting tools

CAST tools for capacity assessment and enhancement:
SOLUTIONS powered by CAST for (pre-)operational capacity planning and demand and capacity balancing

Airspace Capacity

  • Amount of air traffic movements which can be handled by a structure of STAR, approach and SID airspace routes under conditions such as ATC concepts and flight rules (VFR vs IFR)
  • Airspace capacity is defined by the maximum capacity of the weakest element of the airspace and runway
  • CAST Aircraft simulation allows for the assessment of airspace route and sector throughput under dynamic circumstances

ATC Capacity

  • Capability of Air Traffic Control (ATC) to handle air traffic movements (ATM) in the airspace sectors (sector load), taking into account factors such as controller workload and equipment

Maximum Capacity

  • Also referred to as ultimate capacity, saturation capacity or technical capacity
  • Maximum number of throughput through a system under defined conditions
  • Assumes continuous demand, which in reality can only be reached by accepting high delays

Aircraft Stand Capacity

  • Amount of turnarounds which the airside aircraft parking positions can accommodate at any given moment and per unit of time, depending on parameters such as turnaround times
  • Expressed per ICAO code letters (A-F) or as equivalents in case of MARS stands (counted as 2C or 1 E)
  • CAST Stand Allocation can be applied for clarification of stand capacity in case of stand dependencies and test allocation scenarios

Gate Capacity

  • Amount of flights which the terminal infrastructure can handle based on gate availability
  • Distinction is made between arrival and departure gate capacity, as well as the gate status in terms of border control and aviation security
  • Gate capacity/utilisation can be increased by application of swing gates
  • CAST Stand Allocation can be applied to allocate comprehensive flight schedules and ascertain the operational availability of gates. Parameters taken into consideration concern stand geometries/limitations, complex gate/stand dependencies and the gate statuses in terms of border control or aviation security.

Practical Capacity

  • A more generic term to indicate the throughput which can be accommodated for a sustained period of time by the airport infrastructure
  • For the airside of an airport, this concerns the ‘declared capacity’ for runway slot coordination purposes

Declared Capacity

  • At Level 3 slot coordinated airports, demand is considerably close to capacity (in peak periods of the day). In order to guarantee an acceptable level of service in terms of delay, the traffic should not exceed the capacity. Hence a ‘declared capacity’ is defined to ensure the runway is not subject to excessive demand.
  • CAST Aircraft simulation is widely deployed to ascertain declared capacity and the pertaining operational performance in terms of airside delay.

Airport Coordination

  • In those cases when the air traffic demand exceeds the available airport capacity, an airport has to be(come) slot coordinated. In this way, the operational performance and congestion of the airport remains within acceptable levels. This is achieved through a system with ‘slots’, which ensure the demand can be controlled.
  • CAST Aircraft simulation is widely deployed to ascertain declared slot coordination capacity and the pertaining operational performance in terms of airside delay


Selected Customers & Project Airports

Hamad International Airport
Airside Capacity Assessment
A detailed airside capacity study is key for capacity declaration purposes and following slot allocation. This project was carried out in cooperation with IATA. [...]
Bogota El Dorado International Airport
Runway Capacity Analysis and Enhancement
By using a ‘virtual airport’ with CAST Aircraft as testbed for what-if scenarios, operational strategies could be optimized without disturbing the actual traffic flow. [...]
Airport Operations Gaming Platform
This project was carried out as part of the SESAR (Single European Sky ATM Research) initiative, as part of the focus area “Airport Operations Management”. It focused on the development [...]
Moscow-Domodedovo Airport
Runway and Airside Capacity Analysis
Can the planned airside infrastructure cope with the forecasted traffic? Identification of possible bottlenecks by simulation with CAST Aircraft. [...]
DHL Hub Leipzig/Halle Airport
Night Fright Hub Cargo Operations
In an CAST simulation study of aircraft and ground handling processes, measures to meet the high requirements for punctuality and reliability were evaluated. [...]