Marconi Electronic Systems and Embry Riddle University plan to release by 21 May the results of a safety study which shows that head-up-display (HUD) systems can significantly increase safety in the event of smoke and poor visibility on the flight deck.
The study, undertaken after the Swissair Boeing MD-11 accident last year, showed that HUD symbology remains visible through dense smoke for up to 11min longer than a co-located electronic flight instrument system (EFIS). The EFIS is the source of primary flight data to the crew in most contemporary flightdecks.
The test involved setting up a HUD and EFIS in a configuration identical to that of the 737-800 flightdeck. The displays were installed in Embry Riddle's smoke chamber, with video cameras set at pilot eye level. Smoke was introduced until vision was obscured.
Marconi, which is developing a commercial HUD dubbed the Visual Guidance System (VGS), believes the potential safety advantages could be even greater than those suggested by the tests. The EFIS display, for example, did not incorporate the automatic dimming device which adjusts the brightness of the symbology to suit ambient light levels. The trial EFIS was therefore operating at optimum brightness for the whole period. The test team admits, however, that no smoke was ventilated from the chamber during the evaluation, creating a worst-case scenario much faster than a real situation.
Also explored in the tests is the positioning of the umbilical that transfers critical flight data to the HUD. In current configurations, this routes through the side walls aft of the flightdeck, rather than through the floor from the avionics bay. Marconi says the routing would decrease the vulnerability of the HUD to fire damage in the case of an avionics-bay or nose fire.
A second test phase is being discussed, which may include Boeing and Honeywell - which is partnered with Marconi on the development of the VGS. This could include tests of the VGS under varying conditions and with additional sensors. An integrated HUD with infrared forward-looking windshear detection is thought to be one possibility.
Source: Flight International
