HERMES: HEuristic Runway Movement Event Simulation
(02/96 EMF)
1. Model Category
HERMES is a parallel runway capacity evaluation tool. It may potentially be used as a tower controller workload evaluation tool.
2. Summary
HERMES is a fast-time simulation developed by the British Civil Aviation Authority/ National Air Traffic Services (CAA/NATS) to evaluate runway capacity and operations timing under current and future demand and technological improvements. It can also be used to evaluate changes in infrastructure such as runway length modifications. While full airport operations including taxiing are simulated, HERMES puts greatest emphasis on runway operations. HERMES takes experimental recording of aircraft flight paths as input and the principal output is averaged delays. HERMES is effective in providing aggregate results and has been designed to account for the specific rules used at Heathrow for computing very accurate capacity estimates. HERMES is reportedly able to achieve an accuracy of 3/4 movements/24hr, as compared to 12-24 movements/24hr for SIMMOD or TAAM. HERMES also provides detailed simulation of most events occurring during take-off and landing phases.Competing models include TAAM, SIMMOD, and The Airport Machine.
3. Input requirements
The main required input is traffic recordings. HERMES runs on 4-D traffic information obtained from experimental observations. Other inputs include aircraft mix, exit points for each aircraft, times to cross runways and resulting cross-effects on runway capacity. Aircraft are classified by speed and vortex separation categories. Traffic generation may be based on published time tables or from input parameters defining required demand profiles. Additional inputs include simulation parameters such as number of simulation runs. Currently HERMES inputs are mostly based on Heathrow/Gatwick data.
4. Outputs
The main output of HERMES is a file containing average delays to all flights simulated. There is a post processor, written in C, and Excel Macros which consolidate the output files and produce delay statistics graphs. Other outputs include a log file which contains details of all actions performed by every aircraft in a given iteration. These CSV (comma separated variable) files are used for ad hoc analyses of the results. A simple text based graphics output is also available and is a useful debugging tool.
5. Major assumptions
HERMES has been custom designed for Heathrow and Gatwick and the applicability of the software to other airports is undetermined. HERMES supports airports with parallel runways only. The model uses experimental trajectories and does not require transcription of experimental data into a specific formats such as the link-node structure of SIMMOD. Delays are simply propagated across flight trajectories depending on occurring events. Most flight parameters can be randomized.
6. Computational characteristics
Existing code has been written in C. It is a standard PC application. No specific graphics are necessary. Eight MB of RAM are necessary.A typical run takes about 10 minutes to complete. A typical simulation experiment will take approximately 1 to 4 weeks of staff time, depending upon how much analysis of the results is required. These timescales exclude the period required for direct observations of airfield operations, the data validation, and its entry into the simulation.
General and technical information on HERMES can be obtained by contacting David Haydon (011-44-171-832-5601).
The documentation includes file descriptions and a user manual.
7. Learning effort
Unknown.
8. Modularity and Flexibility
Unknown.
9. Status
HERMES is used on a regular basis for evaluation of airport improvements. It is often upgraded. The current version is HERMES II. HERMES III was scheduled to replace HERMES II in March 1996.
10. Extent of model verification
HERMES is used on a regular basis and its output has been compared extensively with real data. The accuracy of HERMES is considered superior to SIMMOD.
11. Principal application
Capacity estimates of infrastructure modifications at Gatwick and Heathrow.
12. Availability
HERMES is proprietary software of CAA/NATS. However, CAA/NATS has a cooperative agreement with the FAA. Any contract awarded by the FAA can access HERMES.
13. Information for model evaluation and contact points
Interview with David Haydon and functional description document for HERMES II.
David Haydon
Directorate of Operational Research and Analysis
National Air TRAFFIC Services
CAA House
45-59 Kingsway
London WC2B 6TE
Tel: 011 44 171 832 5601
Fax: 011 44 171 832 6225
14. Summary evaluation
HERMES is an operational tool used to evaluate airport delays for new configurations. While the model is currently intended for Heathrow and Gatwick operations, it could be applied to other airports as well. The main input for the model is real flight data, which increases complexity, but yields very accurate aggregate results. The need for aggregate results obtained from Monte-Carlo simulations implies quite long simulation times, but achieve very accurate results. HERMES is an appropriate tool to study cases where delays are extremely sensitive to demand variations.
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