A fast-time study on increasing the capacity of continuous descent approaches through airborne precision spacing

摘要

Due to projectedincrea ses in air traffic, there are several research efforts underwayto evaluate ways to safely increase the capacity of the National Airspace System(NAS), improve operational efficiency, andre duce aircraft noise. At NASA LangleyResearch Center (LaRC) in Hampton, Virginia, two parallel research efforts have focusedonterminal area research: one is Airborne Precision Spacing (APS), and theother is the Quiet Aircraft Technologies (QAT) project. The APS objective is toincrease terminal-area capacity without adversely affecting safety, whereas the QATproject objective is to develop noise- and fuel-efficient approach trajectories.The APS project developed a cockpit tool, called Airborne Merging and Spacingfor Terminal Arrivals (AMSTAR), that issues speedco mmands to aircraft to maintaindesired spacing between aircraft pairs. The APS studies showed an ability toincrease runway capacity; however, capacity increases may negatively impact noiseandemissio n levels in airport areas. The QAT project created efficient ContinuousDescent Approaches (CDAs), which showedred uctions in aircraft ground noise andfuel consumption. Previous research has shown that CDA trajectories have adverseeffects on runway capacity because aircraft must be spacedf urther apart at long distancesfrom the runway to prevent separation losses at the runway threshold. Todate, the APS and CDA concepts have been evaluated independently at LaRC.In this study, three different approaches to combining APS and CDA operationswere evaluatedto determine the feasibility and benefits of combining these concepts.These methods combined AMSTAR with 3◦-flight-path-angle-CDA approach routes,3◦-CDA routes with spoilers, and2 ◦-CDA routes without spoilers. Adding the useof spoilers allowedf aster responses to large speedr eductions issued by AMSTAR.This improvement was contrastedwith the effects of a shallower flight-path angle forgreater deceleration capabilities.This research indicated that AMSTAR improved the performance of CDA operations,although full capacity improvements were not achieved. Whereas the 2◦-CDAroutes were expectedto show the best results, the 3◦-CDA case with spoilers showedthe least variability in thresholdspacing errors. All of the CDA routes were morenoise, fuel, and time efficient than traditional step-descent routes that are commonlyusedto day.