Abstract: The What-If System is meant to be a “sandbox” to be able to view the potential impact of system wide changes on the tower side and metering decisions on the ramp side without actually making changes to the system. The What-If System is a tool within which with STBO, RMTC and DASH may be used such that proposed changes and updates can be made to determine their impact in isolation. The What-If System is a prototype tool, we welcome suggestions for improving the What-If utility. Improvements wi…