PVHD meaning in General ?

The peripheral vision horizon display, also called PVHD or the Malcolm Horizon (after inventor Dr. Richard Malcolm), is an aircraft cockpit instrument which assists pilots in maintaining proper attitude.

The PVHD was developed in the mid-1970s and manufactured in the early 1980s as a cockpit instrument to assist the pilot with being better aware of the aircraft attitude at all times. The development of the PVHD was driven by a high incidence of military aircraft accidents due to "attitude awareness issues." The PVHD was noted to have a subliminal effect on the pilot because in actual use the display was set so dim that it could barely be seen.

The PVHD was well received by pilots that tested it in helicopters as well as fixed-wing aircraft. It was flown in F-4s and A-10s, as well as helicopters. Initial production in 1983, however, was for the SR-71 Blackbird as an aid when refueling in the air.

The initial concept demonstration was done in Canadian military laboratories and later development was undertaken by Varian Canada in Georgetown, Ontario. In 1981, Varian sold the project to Garrett Manufacturing in Rexdale, Toronto, Ontario.