Andrew Kendra

Vertical Navigation Displays: Pilot performance and workload during simulated constant-angle-of-descent GPS approaches

This study compared the effect of alternative graphic or numeric vertical navigation aircraft cockpit displays on horizontal and vertical flight technical error, workload, and subjective preference. Displays included (a) a moving map with altitude range arc; (b) the same format, supplemented with a push-to-see profile view, including a vector flight-path predictor; (c) an equivalent numeric display; and (d) a numeric nonvertical navigation display. Sixteen pilots each flew 4 different approaches with each format in a Frasca 242 simulator. Our vertical navigation displays reduced vertical flight technical error by as much as a factor of 2 without increasing workload. Relative advantages of the graphics formats are discussed.

Impact of traffic symbol directional cues on pilot performance during TCAS events

Implementation of Automatic Dependent Surveillance — Broadcast (ADS-B) technology enables aircraft to broadcast, receive and display a number of aircraft parameters that were not previously available to pilots. While significant research has been conducted regarding Cockpit Display of Traffic Information (CDTI) display format, there is little research to assess the impact this additional information would have on pilot response to Traffic Alert and Collision Avoidance System II (TCAS II) Traffic Advisory (TA)/Resolution Advisory (RA) events. The purpose of this study is to determine the impact of providing directionality information for traffic symbols on a TCAS traffic display during a TA/RA event. This issue is particularly relevant for shared TCAS/CDTI displays. The study supported the development of CDTI performance standards through RTCA, Inc. Twenty-three current and qualified Boeing 737 (B737) pilots flew two 35-minute flight segments in a full motion B737 Next Generation (NG) flight simulator, one flight segment with modified symbology that included traffic directionality information and one with standard TCAS symbology that does not directly provide directionality information. During each flight segment, pilots experienced six separate TA/RA encounters that were counter-balanced to vary encounter geometry, phase of flight and visual conditions. Of the 276 planned RA encounters, 251 RAs actually occurred. In some cases, no RA was received due to either pilot maneuvering (22 cases) or simulator issues (three cases). Dependent measures included pilot responses to TCAS TA/RA encounters and pilot use of TCAS displays as measured by eye tracking data. The results indicate that inclusion of traffic directional information on a traffic display during TCAS TA/RA encounters does not negatively affect pilot response to RAs as measured by timing and magnitude of the RA response. Directional information also yielded no observed effect on pilot scans (allocation of gaze). Although effect of symbology was not observed, horizontal and/or vertical maneuvering beyond that commanded by the RA was observed in 90 of 273 possible TCAS TA/RA encounters, independent of symbology. Such maneuvering may be appropriate, depending on the information and context. However, eye tracking and subjective data suggest the maneuvering decisions may be based on the traffic display and not based on visual acquisition or other information. While the overall RA compliance rate was high, the degree of vertical and horizontal maneuvering during the TA/RA event should be better understood since TCAS traffic displays are not intended to support maneuvering. Further research is required to better understand the circumstances in which maneuvering occurs and the resulting impact on the air traffic system.

Examining the Compellingness of electronic Low Visibility Taxi Charts

The purpose of this study was to examine whether the presentation of own-aircraft (ownship) position was compelling when presented on electronic low visibility taxi charts. Although airport charts showing ownship position have been in use for some time, ownship position was not available on low visibility taxi charts because these charts were not geo-referenced. Twenty Airline Transport Pilots (ATP) (10 flightcrews) participated in a simulator study in which they performed six taxi scenarios in three different levels of visibility (1200 Runway Visual Range (RVR), 600 RVR, 300 RVR) using an electronic chart application on an iPad. Ownship position was shown on the chart for half the scenarios. In one scenario, we simulated a position error. We collected objective data (taxi speed, taxi time, fixation and dwell time), and pilot opinions on the usability of the electronic chart application. The results showed that no incursions/excursions were committed. All flightcrews noticed the error in ownship position, when it occurred; in fact, they also noticed other errors in ownship position that were not planned as part of the experiment design. Captains looked more often at the electronic chart when ownship position was presented than when it was not, regardless of visibility conditions. Additionally, Captains’ percentage of fixations were almost equal between the electronic chart and out-the-window. Such behavior may reflect the perceived utility of showing ownship on the electronic chart and may be an indication of the compelling nature of that information source.

Pilots’ Estimation of Altitude of a Small Unmanned Aircraft System (sUAS)

Small unmanned aircraft system (sUAS) operations are growing at a rapid rate, with an increasing number of civilian operations. Currently, the Federal Aviation Administration permits both hobbyist and commercial operations. The requirements for the operations differ; for commercial operations, the sUAS must generally be flown under 400 feet. Past data indicate that operators are poor at judging the altitude of sUAS, and there is variability in the altitude information that is presented to the operator. Here, we examined the ability of commercial and hobbyist sUAS pilots to estimate the altitude of their ownship during a realistic flying task. Participants flew a DJI Phantom 4 Pro to three prescribed altitudes: 50 feet, 200 feet, and 350 feet. In each trial, the participant flew the sUAS from its starting point, hovered at what he or she estimated to be the prescribed altitude, and took a photo of a target. Results indicated that participants’ altitude estimates were below the prescribed altitude of 50 feet 52% of the time, and they were below prescribed altitudes of 200 feet and 350 feet 89% of the time. Despite differences in background, performance did not differ between hobbyist and commercial pilots. Variability in absolute and barometric measurements of altitude was also observed. Taken together, the results suggest that sUAS pilots, regardless of their experience, are poor at judging the altitude of their ownship—especially at higher altitudes. The variability in performance and altitude measurements indicates that pilots need a reliable and standard way to measure the altitude of their ownship, especially given the increasingly complex environments in which sUAS intend to fly.