August - September 2000 - Spatial Disorientation in Army Aviation

By:  Major General Anthony Jones

  Army aviation has a problem. Spatial disorientation continues to be a significant cause of rotary-wing aviation accidents, despite our continued training emphasis on crew coordination during initial-entry rotary wing (IERW) training and instrument flight training for our aviator soldiers.  Let's discuss the magnitude of this problem and the factors that influence its appearance in flight, and introduce some innovative and highly effective training countermeasures that can reduce its threat to our aircrews.

The Problem

                According to the U.S. Army Safety Center, spatial disorientation (SD) was considered to be a significant factor in 291 (30 percent) of Army Class A-C helicopter accidents between 1987 and 1995. One hundred and ten lives were lost, and these accidents resulted in materiel losses of nearly $468 million. Although the monetary cost of SD accidents is high, the fatality rate is between one and one-half to two times that of non-disorientation accidents.

What is SD?

                The human body is structured to perceive changes in movement and orientation on land in relation to the center of the earth. In 1978 researcher A.J. Benson stated "a pilot in an aircraft may fail to correctly sense the position, motion or attitude of the aircraft or of himself within the fixed coordinate systems provided by the surface of the earth and the gravitational vertical."  This condition can be caused or exacerbated by numerous factors singly or in combination, leading to SD. Factors such as loss of situational awareness, task overload, poor aircrew coordination and marginal weather  may all contribute to SD.

                In a definitive 1997 review of SD issues U.S. Army Aeromedical Research Laboratory (USAARL) scientists M. Braithwaite, S. Groh and E. Alvarez concluded that:

                 - SD is an important source of attrition in Army helicopter operations, costing an average of $58 million and 14 lives each year.

                 - SD accidents increased significantly during the Gulf War. The grave implication for the military is highlighted by the fact that 81 percent of nighttime accidents in Saudi Arabia could be attributed to SD.

                 - The contribution of SD to the overall accident rate is not getting smaller. The increased risk associated with the use of night-vision devices compared to day flying is of particular concern.

                 - The helicopter SD accident is not one of classical vestibular or visual illusion giving the pilot "vertigo," but is one of loss of orientation cues leading to a ground or object strike.

                 - These accidents might have been prevented by reinforcing proper crew coordination and scanning techniques.  Continued aircrew SD training will heighten the awareness of the risks associated with distraction and the limitations of human orientation senses.

Countermeasures

                As countermeasures to continuing attrition to SD, USAARL has developed and fielded several programs to heighten awareness of SD in the aviation community. An in-flight demonstration sortie originally designed by the British Army for the Gazelle was modified and tested by USAARL in the UH-1. The sortie was clearly beneficial for demonstrating the physical limitations of the human orientation system.

                The in-flight training sortie was approved by ATB and incorporated into IERW training in 1997.  Due to anticipated funding and asset changes at the U.S. Army Aviation Center, Fort Rucker, Ala., flight training may be affected and may undergo revision. In an effort to be responsive to future training requirements and as the developer of this SD flight training, USAARL is in the process of publishing a report containing the SD demonstration flight lesson plans for the TH-67,  UH-1 and UH-60 helicopters.

                While aviators may have some experience with recovery from unusual attitudes during initial flight training, many disorienting circumstances cannot be demonstrated safely during actual flight. However, it is possible to demonstrate these circumstances safely in a flight simulator. Using data taken directly from real SD accidents, it is possible to recreate and demonstrate these particular orientation problems in a controlled environment in a very realistic manner.

                Simulator flight scenarios have been developed by USAARL for use in training Army aviators to recognize factors, which may lead to spatially disorienting situations. These scenarios are designed to stress situational awareness and proper aircrew coordination techniques to overcome SD once it is encountered. This unique simulator training package permits the trainer to take the aviator through each scenario, and uses the experience as a basis for reinforcing the principles of good situational awareness and aircrew coordination.

                This training package has been distributed to aviation units both within and outside the continental United States, and has received overwhelmingly positive feedback from the Army aviation leaders. We are confident that these scenarios contain valuable training material, and that their use will help decrease SD mishaps.

MG Anthony Jones is commanding general of the U.S. Army Aviation Center at Fort Rucker, Ala., and chief of the aviation branch. Col Powell is commander of the U.S. Army Aeromedical Research Laboratory at Fort Rucker, Ala.

Maj. Gen. Anthony R. Jones is commanding general of the U.S. Army Aviation Center at Fort Rucker, Ala., and chief of the aviation branch.