The Effects of Conditional Clearances on Altitude Deviations

2019Final reportPDFTech ReportDOT-VNTSC-FAA-19-0451FB70Messages (Communications)Air pilotsAir traffic controllersFlight crewsVoice communicationHuman factorsInformation processingAltitudeController Pilot Data Link CommunicationCPDLCData CommDatalinkConditional clearancesLarge Height DeviationsATC clearanceNextGenComplex clearancesUnited StatesJohn A. Volpe National Transportation Systems Center (U.S.)Lennertz, TracyCardosi, KimYost, AlanJohn A. Volpe National Transportation Systems Center (U.S.)United States. Federal Aviation AdministrationVolpe National Transportation Systems Center, Technical Reference CenterThe complexity of communication between pilots and air traffic controllers will increase with the implementation of new traffic management capabilities that depend on Controller Pilot Data Link Communication (CPDLC). Here, we examine the relationship between conditional clearances (defined as messages that include a condition on when an action is to be started or completed) and altitude deviations. The purpose of this analysis is to identify causal and contributing factors to the pilot errors observed and recommend error mitigation strategies. To understand the relationship between conditional clearances and altitude deviations, we analyzed 1) reports submitted to the AviationSafety Reporting System (ASRS), 2) CPDLC communications in United States (US) oceanic airspace from 2014-2017, and 3) recent Large Height Deviations in North Atlantic airspace and altitude deviations reported in the New York Oceanic Control Area. The results further our understanding of human factors issues that contribute to pilot error with complex clearances, and can be used to facilitate the development ofprocedures and training to ensure effective and efficient human system integration in NextGen capabilities.79