What are the flight limitations for part 121 in terms of daily, weekly, monthly, and yearly hours?

The correct flight limitations for part 121 operations specify that a crew member can be scheduled for a maximum of 8 hours of flight time in a single day, 30 hours in a seven-day period, 100 hours in a calendar month, and 1,000 hours in a calendar year. This structure is designed to ensure safety by preventing fatigue among flight crew members, thereby promoting a higher standard of operational safety in airline operations.

Flight time limitations are critical because they mitigate the risk of pilot fatigue, which can significantly affect performance and decision-making in the cockpit. The regulations are aimed at maintaining a balance between operational needs and the well-being of the flight crew. While the other options might present varying limits, only this specific set aligns with the established regulations for part 121 operations, making it the correct answer.