+Gz Exposure and Flight Duty Limitations

Area of Science:

• Aerospace Medicine
• Occupational Health
• Spinal Biomechanics

Background:

• High +Gz exposure is a known risk factor for spinal problems in fighter pilots.
• The tolerable cumulative +Gz exposure and intensity thresholds for spinal health are not well-defined.
• Understanding these limits is crucial for assessing breaking points in a pilot's career and identifying contributing factors to spinal disorders.

Purpose of the Study:

• To identify potential breaking points in a fighter pilot's career related to spinal disorders.
• To evaluate individual factors that may predispose pilots to spinal issues from +Gz exposure.
• To assess the relationship between cumulative +Gz exposure, fatigue index, and permanent flight duty restriction.

Main Methods:

• Survival analysis was conducted on jet pilot trainees from 1995-2015, with the endpoint being permanent flight duty restriction due to spinal disorders.
• Cumulative +Gz exposure was quantified using a fatigue index (FI) recorded sortie by sortie.
• Conditional logistic regression compared FI and other potential confounding factors (flight hours, intensive flying periods, fitness tests, nicotine use) between pilots with spinal restrictions and matched controls.

Main Results:

• The study indicated an annual dropout rate of 0.86% due to spinal problems among fighter pilots.
• No significant difference in the fatigue index (FI) was found between pilots with permanent flight duty restrictions and their controls (OR 0.96, 95%CI 0.87-1.06).
• No statistical differences were observed for flight hours, intensive flying periods, fitness tests, or nicotine product use.

Conclusions:

• No specific career breaking point or individual determinant was identified for Gz-induced spinal disorders.
• The etiology of Gz-induced spinal disorders in fighter pilots appears multifactorial.
• Multifactorial countermeasures are necessary to mitigate the risk and protect pilots' spinal health.