Review of sensor-to-eye latency effects in degraded visual environment mitigations

Abstract

The effect of degraded visual environments (DVE) on aviation is profound. Under reduced-visibility conditions, operational tempo slows to a fraction of its unrestricted-visibility counterpart. Mission capability envelopes are greatly reduced, and some missions cannot be flown. An even more significant problem is the threat of controlled flight into terrain and obstacles, spatial disorientation, and loss of control in flight. Of the 383 Class A and B US military flight accidents between 2002 and 2015, 25% related to operations in DVE and accounted for 81% of the fatalities and $1 billion in lost materiel. In commercial air transport over the past 10 years, there were 1,648 fatalities in 50 accidents due to loss of control in flight. The common theme in these accidents was lack of external visual references. Considerable progress has been made in the development and testing of DVE mitigations, but fielded, operational systems have been elusive. New technologies such as LiDAR, EO/IR, sensor fusion, and helmet-mounted displays (HMDs) are intended to improve pilot performance and expand mission effectiveness. However, much of the effort has focused on separate components. Very little has been devoted to integrated systems, and the human factors components have been all but neglected. This has a detrimental effect on the handling qualities and operational safety of the resulting systems. This paper offers a review of DVE mitigation technology with a focus on human factors requirements for sensor-to-eye latency, monocular, biocular, and binocular display performance, and see-through vs. non-see-through HMD display concepts.