Stephan J.R.P. Carignan

Night Vision Goggle External Lighting Effects

The National Research Council of Canada, Transport Canada and the Federal Aviation Administration examined external lighting and night vision goggle interaction by quantifying the effects of incompatible lighting on visual acuity and recording pilot comments. Four observers and three sets of lights were tested using Landolt ring visual acuity charts created for distances of 15.2, 30.5 and 45.7 m. NVG compatible external lights provided consistent acuity scores in a symmetrically lit visual field. Acuity scores varied greatly with incompatible lights that caused an asymmetric viewing field. Implications for civil NVG operations are discussed.

Development of NVG test maneuvers for civilian aircraft

This document provides an overview of helicopter flight-test methods used to evaluate night vision goggles at the National Research Council of Canadas Institute for Aerospace Research. These techniques have been used to examine the performance of display systems in actual field conditions. The flight evaluations were based, in large part, on standard flight test maneuvers and rating systems outlined in Aeronautical Design Standard ADS-33. The document describes NVG test maneuvers developed from ADS-33 principles, including a high hover, a mirror C, a vertical descent, a parallel lateral translation, a turn about the tail, a confined area staged landing, a brown-out/white-out simulation and a lit pirouette. The overview also comprises a description of methods for controlling the cueing environment. These methods include an appropriate selection of maneuvers as well as devices for limiting pilot vision such as goggles with filters and apertures, and other devices. The paper concludes with a short discussion on the merits of developing accurate in-flight tests capable of resolving performance differences among displays.

Low light comparison of target visibility with night vision goggles

Different night vision goggle image intensification technologies were tested to compare goggle performance in low light conditions. A total of four different night vision goggles were tested in a laboratory dark room. The laboratory tests consisted of viewing Landolt acuity stimuli of different contrast levels with each set of goggles and without the goggles in full light conditions (baseline performance). The results from the laboratory testing indicated that there were significant differences in acuity between the NVGs, particularly for low contrast targets. These data suggest that NVG standards developed using high contrast targets, even in low light conditions may not provide the full story of how the NVG will perform in flight.

Evaluating control activity as a measure of workload in flight test

This paper describes an investigation of a workload measurement technique based on pilot control movements. The Dynamic Interface Modeling and Simulation System Product Metric (DIMSS PM) assumes that pilot control activity can be used to evaluate pilot workload. Three qualified test pilots flew the fly-bywire NRC Bell 205 helicopter in a short test program that compared the DIMSS PM with subjective workload ratings and handling qualities ratings. The pilots performed a variation of an ADS-33E bob-up with varying levels of simulated turbulence and modified cyclic control characteristics. Good agreement was found for most in-flight test conditions between DIMSS Workload Metric scores and subjective workload ratings from the Bedford Workload Scale and Cooper-Harper handling qualities ratings. While, the DIMSS Workload Metric did not accurately reflect workload increases due to variations in the cyclic stick characteristics, the metric shows promise as an objective measurement tool of pilot workload in well-defined tests.

Methodological Issues in Handling Qualities Flight Tests of Helmet -Mounted Display Systems 1

Flight-testing is used to assess the usability and effectiveness of pilot visual systems in the performance of required missions. This paper discusses the flight test techniques used and developed at the Flight Research Laboratory at NRC for evaluating helmetmounted displays. In developing these flight test techniques, it was determined that there are shortcomings in the current Useable Cue Environment (UCE) approach to evaluating visually-coupled systems. They are: 1. Limited subjective scale with poor descriptors and no decision tree; 2. Point cuing dependant upon cones; and, 3. Orientation of the scale with respect to a level 1 rate-damped helicopter. The methodological limitations of the current UCE approach for testing different types of HMDs, including recommendations for improvement are discussed.