Introduction: Sustained operations are the future of any advanced Air Force, which involve round the clock flying operations over a prolonged period. Such operations have the potential of disrupting normal sleep cycle and may cause fatigue among aircrew and ground duty personnel. It is well known that fatigue among crew member is a significant risk to aerospace safety. The present study was hence undertaken to quantify the subjective fatigue and its effects, among the personnel involved in a simulated exercise using Sustained Operations Assessment Profile (SOAP). Material and Methods: SOAP questionnaire, a validated tool, was used for data collection. In the first phase, 1521 personnel involved in the exercise, including aircrew as well as ground duty tradesmen completed the SOAP questionnaires twice during the simulated sustained military operation. The subjective ratings were statistically analyzed using the Wilcoxon matched paired test. The two levels of repeated measures being mean SOAP scores on day 2 and that on day 5. In the second phase, to ascertain differences in the subjective ratings of SOAP among different streams of pilots, data were recorded during another simulated sustained operation after 6 months. A total of 140 aircrew responded to the SOAP questionnaire during 6 days of sustained operations. SOAP score was acquired on day 1 and day 6 of the operations in the second phase. Results: A total of 3042 completed SOAP responses were analyzed. There was a significant increase in ratings of the three cardinal dimensions of SOAP among all personnel. The aircrew rated the subjective effects higher than maintenance or administrative support group. Among the aircrew, the fighter pilots rated significantly higher as compared to transport or helicopter aircrew. Conclusion: The study revealed significant changes in the cardinal dimensions of SOAP among the aircrew who were routinely not involved in shift work (especially fighter pilots). Scientifically designed “shift work” may be an effective strategy to mitigate effects of fatigue during sustained operations, hence, needs to be practiced as a routine by combat Air Force units.