Individual flight hours and crew mission hours are cumulative unless?

• A. A flight plan is filed
• B. Fuel is not available
• C. Maintenance inspection is due
• D. 10 hours of rest are completed.

Answer: (D)

The idea being tested is how rest breaks affect counting of flight and crew hours. These hours build up across flights and missions, but they’re reset when you complete a sufficient rest period. Ten hours of rest is the threshold that breaks the cumulative total, so after such a rest the count starts over for the next duties. This keeps fatigue in check by preventing unchecked hour accumulation.

For example, if you’ve accumulated a set of flight and mission hours and then you complete ten hours of rest, you begin counting again from zero for the next period of duty. Actions like filing a flight plan, fuel availability, or a maintenance inspection due do not reset the hour tally; they’re unrelated to the fatigue-based reset rule.