Changes in hearing thresholds as measured by decibels of hearing loss in British Army Air Corps lynx and apache pilots.

OBJECTIVE: Helicopter pilots are exposed to noise at work and are at risk of developing hearing loss in excess of that which naturally results from aging. We investigated whether Lynx pilots demonstrated changes to hearing thresholds that differed from Apache pilots. METHODS: Survey responses were combined with audiometric data from a retrospective cohort of 59 Lynx and 87 Apache pilots. Subjects' audiograms were analyzed for air conduction thresholds with age correction performed in accordance with ISO 7029. Annual changes in low frequencies (0.5-2 kHz) and high frequencies (3-6 kHz) were calculated. Subjects were categorized for time in service and flying hours. RESULTS: Hearing was better than predicted at nearly all frequencies in both ears for Lynx and Apache pilots. There were no differences in hearing between groups of pilots. Significant differences in hearing threshold changes existed for pilots with 20 or more years of service compared to those in other categories. DISCUSSION: The results suggest that the circumaural earmuffs currently incorporated into the flying helmet mitigate the risk of noise-induced hearing loss in these pilots.

Ten years of spatial disorientation in U.S. Army rotary-wing operations.

INTRODUCTION: Spatial disorientation (SD) has plagued aviation since its inception, contributing to numerous lost lives, destroyed or damaged aircraft, and a reduction in operational mission effectiveness. Military rotary-wing (RW) operations are not immune. The U.S. Army has retired many "legacy aircraft" represented in older studies, developed new training regimens for aircrew, continued to expand its night vision capabilities, and has prosecuted combat operations for some 10 yr utilizing new tactics, techniques, and procedures. For these reasons, it is important and relevant to re-engage the subject of SD among accidents within the Army's RW community. METHODS: The U.S. Army's Combat Readiness/Safety Center database at Fort Rucker, AL, was queried for the previous 10 yr RW mishaps from fiscal year (FY) 2002 through FY 2011 (FY11 current through 01 July). Accidents identified as having SD as a contributing factor were selected. RESULTS: From FY 2002 to FY 2011, there were 100 Class A through C rotary-wing flight mishaps involving SD. This represents 11% of all Class A through C rotary-wing flight accidents for this period. Of the 100 SD-related accidents, 22% involved fatalities, and 39% involved fatalities and/or injuries. The total number of RW SD-related accidents with fatalities represents 31% of the total helicopter accidents with fatalities for the 10-yr period. DISCUSSION: This review of accident data confirms that SD remains a substantial issue for the Army aviation community and reinforces the importance and relevance of SD awareness, research, education, and training in RW operations.

Survey of spatial disorientation in military pilots and navigators.

BACKGROUND: The direction of future spatial disorientation (SD) research and training is shaped primarily by the outcome of formal investigation of aircraft accidents and incidents. However, another source of vital information is aircrews' experience of SD that does not result in reported incidents. METHODS: A short postal SD survey was distributed to 5 Naval Air Squadrons, 22 Joint Helicopter Command Units, and 7 Royal Air Force stations in the United Kingdom. There were 752 questionnaires, including responses from 562 pilots and 149 navigators, that were returned. RESULTS: Analysis was conducted primarily on the pilot data. The most frequently experienced SD episodes were "the leans" (by 92% of respondents), loss of horizon due to atmospheric conditions (82%), misleading altitude cues (79%), sloping horizon (75%), and SD arising from distraction (66%). In general, the frequency of SD episodes and ratings of severity of the worst ever SD episode were positively related to flying experience (p < 0.05). Overall, pilots who had received in-flight SD training reported more episodes of SD than those who had not participated in this training (p < 0.05). Differences in types of SD experienced were found between aircraft categories, e.g., more episodes of SD during night vision goggle use were reported by rotary-wing pilots compared with fast-jet aviators (p < 0.05). CONCLUSIONS: This preliminary survey has shown that SD is still a significant hazard of military flying. Overall, this study shows that the postal questionnaire is a useful tool for assessing how SD training and experience may benefit the recognition of situations that may cause SD. However, it is difficult to access those situations where aircrew were truly disorientated.