The HUD as Primary Flight Instrument

The historical status of the Head Up Display (HUD) as Primary Flight Instrument in both military and civil applications is reviewed. The rôle of the HUD in air carrier applications as a landing aid is considered in detail. An architecture is presented for a HUD suitable for CAT IIIB and CAT IIIC approaches, and for integration into the wider avionics system to provide full-time primary flight instrument benefits.