Initial safety evaluation of the Unified Departure Operation Spacing (UDOS) standard concept

■ UDOS Application - Enables reduced in-trail spacing ▪ Initial spacing effectively reduced from typically 3.0 NM to 2.2 NM ■ Spacing Decompression - Within 10 NM: ▪ Over 95 percent of departure spacing decompresses to currently required minimum separation or more ▪ Increased need for ATC mitigation limited to less than 5 percent of departure operations ■ Need for ATC Mitigation - More frequent need typically limited to a few percent of departure operations - Limited impact on controller workload in case of conventional mitigation strategies - Impact further reduced with application of PBN departure procedures ▪ Defined divergence waypoint and sequencing of departing aircraft for alternating use ■ Applicability - Identified 21 airports in the NAS for potentially beneficial UDOS spacing applications ▪ The airports are currently constrained by operational, procedural, environmental, regulatory, and/or other constraints that preclude conducting diverging departure operations