Analysis of RNAV arrival operations with descend via clearances at phoenix airport

On 10 October 2006, two new area navigation (RNAV) arrival procedures for Phoenix Sky Harbor International Airport (PHX) were published which provide vertical guidance in the terminal area. The procedures largely overlay corresponding conventional procedures and established navigation patterns used by air traffic control (ATC). However, the inclusion of vertical guidance and routine ATC issuance of descend via clearances to leverage this guidance was expected to result in more continuous aircraft arrival descents inside the terminal area. More continuous descents enable prolonged flight under reduced engine thrust and associated fuel burn and environmental benefits. The MITRE Corporation's Center for Advanced Aviation System Development (CAASD) was tasked by the Federal Aviation Administration (FAA) to assess operational changes associated with the implementation of the new RNAV arrival procedures at PHX and estimate the resulting user benefits. Based on analysis of radar data recorded during eleven days of pre-and post-implementation operations, significant improvements in descent continuities were observed for aircraft descending via the new procedures. The improvements resulted in a 38-percent reduction in the time aircraft remained in level flight at key step-down altitudes in terminal airspace. Fuel burn benefits to users were estimated at $0.5 million annually, and resulting reductions in CO2 emissions were estimated at approximately 2500 metric tons annually. In addition to these currently realized benefits, improved participation coupled with procedure optimization efforts promise increased future user benefits.