Which changes require re-authorization by the T1 controller?

• A. Change of Crewmembers
• B. Number of legs
• C. Increase in schedules flight hours by more than 1 hour
• D. All of the above

Answer: (D)

In Part 135 operations, anything that changes who is qualified to fly, how far you’ll fly, or how long you’ll be in the air needs a fresh sign-off from the person responsible for operational control—the T1 controller. That ensures the operation stays within the certificate’s limits and that safety, fatigue, and compliance are rechecked for the new conditions.

Change of crewmembers requires re-authorization because a new crew, even if skilled, must meet the specific flight-time, rest, currency, and qualification requirements before they can operate. Re-authorization confirms the roster is still compliant and that the crew available for duty is appropriate for the flight.

Changing the number of legs alters the route structure and the total time airborne, which affects scheduling, fuel planning, and crew duty periods. The updated route must be reviewed to verify it still fits the approved operating plan and regulatory constraints.

An increase in scheduled flight hours by more than one hour changes fatigue risk and could push operations beyond what was initially authorized. Re-authorization ensures the plan accounts for the additional hours, including rest, maintenance, and any necessary mitigations.

So, all of these kinds of changes trigger a re-authorization by the controller in charge of operations to keep the flight within approved limits and maintain safety.