Monica F. Hughes

Nasa Synthetic Vision Ege Flight Test

NASA Langley Research Center conducted flight tests at the Eagle County, Colorado airport to evaluate synthetic vision concepts. Three display concepts (size “A” head-down, size “X” head-down, and head-up displays) and two texture concepts (photo, generic) were assessed for situation awareness and flight technical error / performance while making approaches to Runway 25 and Runway 07 and simulated engine-out Cottonwood 2 and KREMM departures. The results of the study confirm the retrofit capability of the HUD and Size “A” SVS concepts to significantly improve situation awareness and performance over current EFIS glass and non-glass instruments for difficult approaches in terrain- challenged environments.

Terrain portrayal for read-down displays flight test

The Synthetic Vision Systems General Aviation (SVS-GA) element of NASAs Aviation Safety Program is developing technology to eliminate low visibility induced General Aviation (GA) accidents through the application of synthetic vision techniques. SVS displays present computer generated 3-dimensional imagery of the surrounding terrain to greatly enhance pilots situation awareness (SA), reducing or eliminating Controlled Flight into Terrain (CFIT), as well as Low-Visibility Loss of Control (LVLOC) accidents. In addition to substantial safety benefits, SVS displays have many potential operational benefits that can lead to flight in instrument meteorological conditions (IMC) resembling those conducted in visual meteorological conditions (VMC). Potential benefits could include lower landing minimums, more approach options, reduced training time, etc. SVS conducted research will develop display concepts providing the pilot with an unobstructed view of the outside terrain, regardless of weather conditions and time of day. A critical component of SVS displays is the appropriate presentation of terrain to the pilot. The relationship between the realism of the terrain presentation and resulting enhancements of pilot SA and pilot performance has been largely undefined. Comprised of coordinated simulation and flight test efforts, the terrain portrayal for head-down displays (TP-HDD) test series examined the effects of two primary elements of terrain portrayal: variations of digital elevation model (DEM) resolution and terrain texturing. Variations in DEM resolution ranged from sparsely spaced (30 arc-sec/2,953ft) to very closely spaced data (1 arc-sec/98 ft). Variations in texture involved three primary methods: constant color, elevation-based generic, and photo-realistic, along with a secondary depth cue enhancer in the form of a fishnet grid overlay. The TP-HDD test series was designed to provide comprehensive data to enable design trades to optimize all SVS applications, as well as develop requirements and recommendations to facilitate the implementation and certification of SVS displays. The TP-HDD flight experiment utilized the NASA LaRC Cessna 206 Stationaire and evaluated eight terrain portrayal concepts in an effort to confirm and extend results from the previously conducted TP-HDD simulation experiment. A total of 15 evaluation pilots, of various qualifications, accumulated over 75 hours of dedicated research flight time at Newport News (PHF) and Roanoke (ROA), VA, airports from August through October, 2002. This report will present results from the portion of testing conducted at Roanoke, VA.

Interaction between various terrain portrayals and guidance/tunnel symbology concepts for general aviation synthetic vision displays during a low en-route scenario

In support of the NASA Aviation Safety Programs Synthetic Vision Systems (SVS) Project, a series of piloted simulations were conducted to explore and quantify the relationship between candidate terrain portrayal concepts and guidance/tunnel symbology concepts, specific to General Aviation (GA). The experiments were conducted in a fixed based flight simulator equipped with two separate 6-inch Liquid Crystal Display (LCD) Head Down Displays, one serving as a glass cockpit style Primary Flight Display (PFD) and the other as a Navigation Display (ND). This work is the second part of a three-part study related to the Symbology Development for Head Down Displays (SD-HDD) test series. The focus of this experiment was on advanced low altitude en route maneuvers simulating a transition into Instrument Metrological Conditions (IMC) in the central mountains of Alaska (Merrill Pass). A total of 18 GA pilots, with three levels of pilot experience, evaluated a test matrix of four terrain portrayal concepts (TPC) and six guidance/tunnel symbology (GSC) concepts. Both quantitative and qualitative measures were recorded and analyzed. Quantitative measures included all pilot/aircraft performance data, flight technical errors (FTE), flight control inputs, and selected physiological data. The qualitative measures included pilot comments and pilot responses to the structured questionnaires such as perceived workload, subjective Situation Awareness (SA), pilot preferences, and the rare event recognition. Only a sample of the results of FTE, SA and workload is reported here. There were statistically significant effects found from GSC and TPC but no significant interactions between TPCs and GSCs for this experiment. Lower FTE and increased SA were achieved using SVS displays, as compared to the baseline Pitch/Roll Flight Director (PRFD) and Blue Sky Brown Ground (BSBG) combination. These results indicate that all pilots performed very well, mostly within the 75ft of vertical and lateral limits indicated by one dot of the course deviation indicators. With the same SVS training provided to all three groups, low time VFR pilots performed as well as IFR pilots in low altitude en-route scenario with IMC. Overall those GSCs that have both Guidance Cue and Tunnel performed better than the other concepts.

Synthetic Vision CFIT Experiments for GA and Commercial Aircraft: "A Picture Is Worth A Thousand Lives"

Because restricted visibility has been implicated in the majority of commercial and general aviation accidents, solutions will need to focus on how to enhance safety during instrument meteorological conditions (IMC). The NASA Synthetic Vision Systems (SVS) project is developing technologies to help achieve these goals through the synthetic presentation of how the outside world would look to the pilot if vision were not reduced. The potential safety outcome would be a significant reduction in several accident categories, such as controlled-flight-into-terrain (CFIT), that have restricted visibility as a causal factor. The paper describes two experiments that demonstrated the efficacy of synthetic vision technology to prevent CFIT accidents for both general aviation and commercial aircraft.

The Efficacy of Using Synthetic Vision Terrain-Textured Images to Improve Pilot Situation Awareness

The General Aviation Element of the Aviation Safety Program’s Synthetic Vision Systems (SVS) Project is developing technology to eliminate low visibility induced General Aviation (GA) accidents. SVS displays present computer generated 3-dimensional imagery of the surrounding terrain on the Primary Flight Display (PFD) to greatly enhance pilots situation awareness (SA), reducing or eliminating Controlled Flight into Terrain, as well as Low-Visibility Loss of Control accidents. SVSconducted research is facilitating development of display concepts that provide the pilot with an unobstructed view of the outside terrain, regardless of weather conditions and time of day. A critical component of SVS displays is the appropriate presentation of terrain to the pilot. An experimental study is being conducted at NASA Langley Research Center (LaRC) to explore and quantify the relationship between the realism of the terrain presentation and resulting enhancements of pilot SA and performance. Composed of complementary simulation and flight test efforts, Terrain Portrayal for Head-Down Displays (TP-HDD) experiments will help researchers evaluate critical terrain portrayal concepts. The experimental effort is to provide data to enable design trades that optimize SVS applications, as well as develop requirements and recommendations to facilitate the certification process. In this part of the experiment a fixed based flight simulator was equipped with various types of Head Down flight displays, ranging from conventional round dials (typical of most GA aircraft) to glass cockpit style PFD’s. The variations of the PFD included an assortment of texturing and Digital Elevation Model (DEM) resolution combinations. A test matrix of 10 terrain display configurations (in addition to the baseline displays) were evaluated by 27 pilots of various backgrounds and experience levels. Qualitative (questionnaires) and quantitative (pilot performance and physiological) data were collected during the experimental runs. This paper focuses on the experimental set-up and final physiological results of the TP-HDD simulation experiment. The physiological measures of skin temperature, heart rate, and muscle response, show a decreased engagement (while using the synthetic vision displays as compared to the baseline conventional display) of the sympathetic and somatic nervous system responses which, in turn, indicates a reduced level of mental workload. This decreased level of workload is expected to enable improvement in the pilot’s situation and terrain awareness.

Initial development of a metric to describe the level of safety associated with piloting an aircraft with synthetic vision systems (SVS) displays

Synthetic Vision Systems (SVS) displays provide pilots with a continuous view of terrain combined with integrated guidance symbology in an effort to increase situation awareness (SA) and decrease workload during operations in Instrument Meteorological Conditions (IMC). It is hypothesized that SVS displays can replicate the safety and operational flexibility of flight in Visual Meteorological Conditions (VMC), regardless of actual out-the-window (OTW) visibility or time of day. Throughout the course of recent SVS research, significant progress has been made towards evolving SVS displays as well as demonstrating their ability to increase SA compared to conventional avionics in a variety of conditions. While a substantial amount of data has been accumulated demonstrating the capabilities of SVS displays, the ability of SVS to replicate the safety and operational flexibility of VMC flight performance in all visibility conditions is unknown to any specific degree. The previous piloted simulations and flight tests have shown better SA and path precision is achievable with SVS displays without causing an increase in workload, however none of the previous SVS research attempted to fully capture the significance of SVS displays in terms of their contribution to safety or operational benefits. In order to more fully quantify the relationship of flight operations in IMC with SVS displays to conventional operations conducted in VMC, a fundamental comparison to current day general aviation (GA) flight instruments was warranted. Such a comparison could begin to establish the extent to which SVS display concepts are capable of maintaining an “equivalent level of safety” with the round dials they could one day replace, for both current and future operations. Such a comparison was the focus of the SVS-ES experiment conducted under the Aviation Safety and Security Programs (AvSSP) GA Element of the SVS Project at NASA Langley Research Center in Hampton, Virginia. A combination of subjective and objective data measures were used in this preliminary research to quantify the relationship between selected components of safety that are associated with flying an approach. Four information display methods ranging from a “round dials” baseline through a fully integrated SVS package that includes terrain, pathway based guidance, and a strategic navigation display, were investigated in this high fidelity simulation experiment. In addition, a broad spectrum of pilots, representative of the GA population, were employed for testing in an attempt to enable greater application of the results and determine if “equivalent levels of safety” are achievable through the incorporation of SVS technology regardless of a pilots flight experience.

Symbology Development for General Aviation Synthetic Vision Primary Flight Displays for the Approach and Missed-Approach Modes of Flight

Spatial disorientation induced by inadvertent flight into instrument meteorological conditions (IMC) continues to be a leading cause of fatal accidents in general aviation. The Synthetic Vision Systems – General Aviation (SVS-GA) research element, an integral part of NASAs Aviation Safety and Security Program (AvSSP), is investigating a revolutionary display technology designed to mitigate low visibility events such as controlled flight into terrain (CFIT) and low-visibility loss of control (LVLOC). The integrated SVS Primary Flight Display (SVS-PFD) utilizes computer generated 3-dimensional imagery of the surrounding terrain augmented with flight path guidance symbology. This unique combination will provide GA pilots with an accurate representation of their environment and projection of their flight path, regardless of time of day or out-the-window (OTW) visibility. The initial Symbology Development for Head-Down Displays (SD-HDD) simulation experiment examined 16 display configurations on a centrally located high-resolution PFD installed in NASAs General Aviation Work Station (GAWS) flight simulator. The results of the experiment indicate that situation awareness (SA) can be enhanced without having a negative impact on task performance, by providing a general aviation pilot with an integrated SVS display to use when OTW visibility is obscured.

Effectively Transforming IMC Flight Into Vmc Flight: An Svs Case Study

A flight-test experiment was conducted using the NASA LaRC Cessna 206 aircraft. Four primary flight and navigation display concepts, including baseline and synthetic vision system (SVS) concepts, were evaluated in the local area of Roanoke Virginia Airport, flying visual and instrument approach procedures. A total of 19 pilots, from 3 pilot groups reflecting the diverse piloting skills of the GA population, served as evaluation pilots. Multi-variable discriminant analysis was applied to three carefully selected and markedly different operating conditions with conventional instrumentation to provide an extension of traditional analysis methods as well as provide an assessment of the effectiveness of SVS displays to effectively transform IMC flight into VMC flight