INVESTIGATION ON THE EFFECTS OF AIRPORT ATFM RESTRICTIONS

1. INVESTIGATION ON THE EFFECTS OF AIRPORT ATFM RESTRICTIONS Thomas Günther Prof. Dr.-Ing. Hartmut Fricke ICRAT 2004 Zilina, 23.11.04

2. Content • Background & motivation • Computer-aided model • Investigation & results • Conclusions • Institute of Aviation, Dresden

3. Investigation background • ATFM (Air Traffic Flow Management) objectives: • improve safety by avoiding overloads of sectors and controllers • enable an optimum traffic flow within the airspace • in Europe provided by the CFMU (Central Flow Management Unit) • comparison of the demand forecast with capacities of each ATC sector and airport ATFM restrictions if demand exceeds capacity • all flights concerned with this restriction will be delayed at their departure airport (slot allocation)

4. Motivation • most penalizing airport: Frankfurt Main (more than 1 million minutes of ATFM delay in 2003, much more than any other European airport) • 2nd: Roma Fiumicino: 610 000 minutes ATFM delay in 2003 • 3rd: London Heathrow: 590 000 minutes ATFM delay in 2003 • En-route ATFM delays decreased since 1999 by about 75%  Airport ATFM delays are becoming more important nowadays

5. Computer-aided model Requested inputs: Scheduled Times of Arrival, … ETA generation (propability distribution) Modeling of the slot allocation process Discrepancies between regulated and actual demand Modeling of the arrival sequencing process Actual Times of Arrival, arrival demand & flow, ...

6. Investigation • Investigation on ATFM restrictions at Frankfurt Main Airport: • declared capacity of 43 (45) arrivals/h in 2003 • in case of poor weather conditions explicit lower capacity (CAT II/III conditions: about 35 arrivals per hour) • investigation on the effects with and without ATFM restrictions

7. Results:Effects on actual demand Simulation of a regulated demand of 35 arrivals/h between 7:00 and 8:00: actual demand decreases within the period of ATFM restriction after cancellation of the restriction the demand increases (late arrivals) a too early applied restriction may lead to negative effects (flights are pushed into the critical period) ATFM restriction

8. Results:Effects on airborne delay Simulation of a maximum arrival rate of 35 per h between 7:00 and 8:00: airborne delay can be reduced by implementing ATFM restrictions communication and surveillance workload for the controllers can be reduced safety is improved by avoiding overload of airspace and controllers

9. Results:Effects on punctuality Simulation of a maximum arrival rate of 35 per h between 7:00 and 8:00: punctuality is decreased by the application of Airport ATFM restrictions reduction of airborne delay is always less than subsequent increase of ATFM delay reason: better runway throughput without ATFM restrictions

10. Conclusions • Airport ATFM restrictions need to be applied to ensure safety if a capacity reduction or excessive demand may lead to significant airspace congestion. • To maintain a tolerable punctuality a good balance between ATFM restrictions and the use of available holding stacks has to be achieved. • Objective of Airport ATFM restrictions: • NOT to avoid holding! • Maintain safety requirements while keeping airborne holding at a manageable and efficient level Ground Holding Safe and efficient balance Airborne Holding

11. Institute of Aviation, Dresden • Director of the institute: Professor Hartmut Fricke • young team (9 assistants) of aviation experts and engineers • key aspects of research: • Air Transport Infrastructure Planning • Air Transport System Technologies • Optimizing Ground Handling and Passenger Flow Processes • Capacity Analysis: Correlating Capacity and Safety

12. Thank you for your attention!