Furthermore, a low-precision cue presented on an HMD had some disruptive effect on other displayed tasks, an effect that was not observed when the cue was presented on the head-down display.
Here, the increased clutter at the head-up location disrupted target detection relative to the head-down display. The increased difficulty may be attributable to the fact that the additional clutter in the HMD imagery degraded the visibility of the forward field of view to such an extent that peripheral information regarding the location of the targets, which may have helped to guide detection in the less-cluttered display in Experiment 1, was no longer available.
(1999) found a significant effect of display platform, such that attentional tunneling was reduced more with the use of a handheld display than with the HMD, whereas no such difference between head-up and head-down display conditions was reported here.
"In the future, the technology with synthetic vision is moving toward a head-down display," he said.
Evaluation pilots from the 412th Flight Test Squadron and the Air Force Test Pilot School also conducted blind low-level profiles and approaches using head-up and head-down displays that were equipped with synthetic-vision elements.
Given that Experiment 1 (in a comparison between a head-up and a head-down display) raises the possibility that clutter may eliminate the HUD advantage in response to unexpected events, clutter costs in HUDs should not be discounted.
Although the current data provided no evidence that a head-down display was superior for any task, the absence of the HUD benefit in response to unexpected events in Experiment I does not exclude the possibility of interference from visual clutter, a consequence of superimposed images.
Commercial Systems sales dropped 21 percent to USD1.89 billion, whereas the Airborne Systems unit was up 6 percent at USD1.76 billion, with help from higher sales of head-down displays
for Boeing F-15s and unmanned air vehicle control systems.
The ITD is equipped with a MK16A ejection seat replica, Hotas, rudder/brake pedals, and all multi-functional head-up and head-down displays
, control panels and switches.
Thomson-CSF's Avionics Division concentrated on head-up, head-level and head-down displays
as well as on the development of new-generation liquid-crystal flat screens, Crouzet on navigation equipment (including laser gyroscopes and space-oriented systems), Electronique Aerospatiale on radios and Sfena on control systems; there was a slight product overlap in flight instruments.