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Nextgen Flight Deck Surface Trajectory-based Operations (stbo): Speed-based Taxi Clearances
| Content Provider | Semantic Scholar |
|---|---|
| Author | Bakowski, Deborah L. Foyle, David C. Kunkle, Christina L. Hooey, Becky L. Jordan, Kevin E. |
| Copyright Year | 2011 |
| Abstract | A pilot-in-the-loop simulation was conducted that required pilots to taxi following acceleration and speed profiles under two Speed-conformance conditions (Defined and Undefined). Pilots were given a commanded speed in both conditions, however, in the Defined Speed-conformance condition, air traffic control (ATC) issued alerts when the aircraft speed exceeded a +/- 1.5 kt speed range. A current-day, baseline trial with no required speed profile was also included. While pilots achieved required time of arrival (RTA) errors of less than 10 sec in each condition, both Speed-conformance conditions produced more visual fixation time on the speed tape, located head-down on the primary flight display (PFD), compared to the baseline condition. Fourteen out of eighteen pilots reported that the demand of maintaining the required speed conformance range in actual operations would compromise safety. These results indicate the need for advanced flight deck displays to enable pilots to safely comply with runway RTAs during taxi. The present study investigated the taxi-out departure environment (from the ramp area to the runway) of the next generation (NextGen; JPDO, 2009) of the National Airspace System. Current research efforts are aimed toward the development of surface traffic management (STM) systems for air traffic control (ATC) to provide optimized taxi clearances that eliminate active runway crossing delays and enable more efficient use of runways. These taxi clearances would have a speed- or time-based component with which the pilot must comply. These NextGen taxi operations have been referred to as “4-D taxi” (with the fourth dimension referring to the time component), or surface trajectory-based operations (STBO). STM systems are envisioned to use dynamic algorithms to generate speed- or time-based taxi clearances for aircraft to calculate the most efficient movement of all surface traffic and enable precise surface coordination (Cheng, Yeh, Diaz, & Foyle, 2004; Rathinam, Montoya, & Jung, 2008). To accomplish the required precision, the STM system provides speed/time commands to pilots throughout the taxi route, such that they arrive at certain airport “traffic flow points” (e.g., traffic merge points, active runway crossings, etc.) at specific times. The aircraft’s speed may need to be adjusted if the pilot is unable to conform to the STBO command, or if traffic is unable to comply creating a reduction in separation, or to meet the needs of the dynamic airport surface. Previous Research Foyle, Hooey, Kunkle, Schwirzke, and Bakowski (2009) investigated the impact of speed commands on pilots’ ability to meet a required time of arrival (RTA) at traffic flow points between a ramp departure spot and the runway. The goal of the study was to drive aircraft to a specified location (runway end or traffic flow point) at a specific time by having ATC provide the pilot a taxi clearance with a commanded speed to be followed. (Note that speed is the parameter that pilots actually control via throttle inputs ‐ arrival time derives from that speed control. If ATC provided clearances with a time requirement, pilots would have to transform that into speed, taking route distance into account.) In the ‘Limited’ NextGen condition 1 , the Primary Flight Display (PFD) presented the commanded and current ground speeds. Trials consisted of 1, 3, or 5 segments, where each segment had a commanded speed of 10, 14, 18, or 22 kts. Because the total distance of all trials was similar, segment distance in one-segment trials was longer than in the three- or five-segment trials. Pilots were instructed to comply with the commanded speed on straight segments, accelerate/decelerate “aggressively”, and, for commanded speeds of 18 and 22 only, slow to 15 kts for turns. The RTA was originally calculated using the taxi route segment length and the ATC-commanded speed for the straight segments. The primary measure of performance was time of arrival (TOA) error, calculated by subtracting the RTA from the observed arrival time at each segment transition. The results indicated TOA errors of -24 sec (early) to 53 sec (late) for one-segment trials. However, it was noted that the RTA 1 The study examined two conditions of speed commands, which varied according to the complexity of the flight deck avionics, however only the ‘Limited’ NextGen condition is discussed here. |
| Starting Page | 44 |
| Ending Page | 44 |
| Page Count | 1 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://corescholar.libraries.wright.edu/cgi/viewcontent.cgi?article=1008&context=isap_2011 |
| Alternate Webpage(s) | https://human-factors.arc.nasa.gov/groups/HCSL/publications/Bakowski_et_al_2011_ISAP%20Paper.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
