A COCKPIT-BASED indicator system which could help fighter pilots maintain the desired attitudes while flying in low-visibility conditions is being developed by the UK's Defence Research Agency (DRA).
The ambient attitude indicator (AAI) consists of a canopy-arch-mounted strip of lights, which provides pilots with peripheral visual information on aircraft position.
Roger Green, chief scientist at the DRA's Centre for Human Sciences, which is developing the AAI, says that the system is designed to make instrument flying feel a little more like visual flying by driving the pilot's ambient visual system with peripheral, textured, world-stabilised information.
"The AAI aims to provide the same information as conventional attitude-indicator instruments, but in a way that minimises the risk of pilot disorientation," Green says. The system is not designed to help a pilot recover from unusual attitudes, but to prevent reading these attitudes in the first place.
Spatial disorientation accounts for an average 8% of military-aircraft accidents in the UK, according to DRA figures. In non-visual flights the aircraft becomes the pilot's frame of reference, a condition which could result in a loss of spatial awareness outside the cockpit.
Cockpit instruments drive the pilot's focal visual system, requiring conscious decisions on aircraft control, but by providing perceptual information, the pilot "...could be trained to make these decisions subconsciously," Green claims.
"The AAI becomes part of the pilot's control 'loop', providing undetailed spatial information in his peripheral vision." The light strip is made up of 400 light-emitting diodes (LEDs) which are 3mm wide and which are linked to the aircraft's main flight-computer. Two clusters of up to eight LEDs light up where the horizon crosses the canopy arch on either side of the cockpit. As the aircraft rolls, the lights maintain the horizon by tracking movement up and down.
The DRA plans to test the AAI on a Royal Air Force British Aerospace Hawk based at Boscombe Down in the UK. The University of Cranfield's Microprocessor Group has developed the software for the system as part of the UK Ministry of Defence-funded project.
According to Green, the aim of the trials, which could lead to commercial-aviation applications, is to familiarise the pilot with the AAI in visual conditions, gradually moving to non-visual flying as the system becomes established.
See Military Safety, P34.
Source: Flight International
