Critical issues:

• Already operating at near capacity and with the building of another runway years away, the only option at Frankfurt Main Airport for increasing capacity was to improve the utilisation of existing runways
• It was critical that the safety implications of any changes were assessed fully so that risk could be effectively managed
• DFS also needed regulatory approval for any deviations from International Civil Aviation Organisation (ICAO) accepted practices and standards

Solutions:

• We assessed the safety of the proposed system in two phases:
• • Safety assessment of the concept – was it safe with respect to wake vortex and collision risks?
  • Assessment of detailed operational hazards
• Specially designed models were used to make quantitative estimates of wake vortex risk, in which the measured distributions of aircraft were key inputs
• A relative risk assessment was conducted and showed that the risks of the Reduced Diagonal Separation Minima (RDSM) concept were no higher than equivalent ICAO in-trail scenarios
• The analysis of detailed operational hazards involved brainstorming with pilots, controllers, system designers and safety experts

Value delivered:

• DFS and its partners were able to safely introduce capacity enhancement measures at Frankfurt Main Airport
• The safety assessment helped DFS identify measures for ensuring that risk had been reduced as far as reasonably practicable
• Improved stakeholder awareness of safety issues and ultimately acceptance of the proposed change