Which of the following is a legitimate reason to limit a first officer's ability to fly?

Limiting a first officer’s ability to fly at a special qualification airport is a legitimate reason due to the specific operational requirements that may be necessary at such locations. Special qualification airports often have unique challenges such as challenging terrain, specific weather considerations, or operational limitations that necessitate higher levels of training and experience. First officers must have the appropriate qualifications and may need to demonstrate familiarity with the procedures and conditions unique to those airports to ensure safety.

In contrast, having less than 50 hours in the aircraft could indicate a need for additional experience, but it does not automatically preclude the first officer from flying, especially if they are paired with a more experienced captain. Age requirements may pertain to regulations regarding licensing and minimum age for certain operating positions, yet they may not necessarily be a disqualifying factor if the individual meets other experience qualifications. Lastly, having flown that exact route before usually does not limit a first officer’s ability; in fact, prior experience on a route is generally viewed as an asset.