Toward the goal … reducing mishaps by 50%

Approach, May-June, 2004 by Nicolas Webster

Spatial disorientation (SD) is a normal response of a normal human to the abnormal environment of flight. Humans are terrestrial born and bred, and the systems that orient us to up and down are designed to work when we are attached firmly to the ground, or return us to the ground in an upright position. The body's spatial orientation systems were not designed for prolonged flight.

About 100 years ago, man entered the air in dynamic flying machines and quickly realized flight was a very hazardous environment. We soon learned that when we lost our peripheral-visual inputs of the horizon, very bad things start to happen, and the ground and sky are not where we think they are. For many years flight was a daytime visual activity until the development of instruments to assist in orientation. Even with modern instruments, aviators still manage to crash aircraft at a staggering rate because they continue to have difficulty adapting to the abnormal flight environment.

Researchers at the Naval Aerospace Medical Research Laboratory (NAMRL) in Pensacola, Fla., reviewed all naval Class A flight mishaps from 1997 though 2002, to identify the occurrence of SD. They used this definition to identify the mishaps: Spatial disorientation describes "a variety of incidents occurring in flight where the pilot fails to sense correctly the position, motion or attitude of the aircraft, or of himself within the fixed co-ordinate system provided by the surface of the earth and the gravitational vertical." SD also refers to "errors in perception by the pilot of his position, motion or attitude with respect to his aircraft, or of his own aircraft relative to other aircraft"

The study revealed the magnitude of lives and assets lost to the hazard of spatial disorientation in naval aviation.

FY97 to FY02 Rotary Wing Aircraft

* 47 Total mishaps--rate 1.94 per 100,000 flight hours

* 65 Total deaths

* 14 SD mishaps--rate 0.58 per 100,000 flight hours, cost $118,251,279

* 35 SD deaths

FY97 to FY02 Fixed Wing Aircraft

* 120 Total mishaps--rate 1.81 per 100,000 flight hours

* 100 Total deaths

* 22 SD Mishaps--rate 0.33 per 100,000 flight hours, cost $475,909,083

* 23 Deaths

The following series of articles provides additional information on the hazards associated with spatial orientation in flight, and some technological advancements being fielded or evaluated for future incorporation into aviation platforms. We're also including a few "There I was" articles to show how dangerous SD can be.

Capt. Webster is the aeromedical division head, Naval Safety Center.