How many passengers can the MCD stairs accommodate at one time?

The correct answer indicates that the MCD stairs can accommodate four passengers at one time. This design allows for a safe and efficient boarding process, ensuring that multiple passengers can use the stairway simultaneously without causing delays or bottlenecks. Accommodating four passengers aligns with safety protocols, as it helps maintain a steady flow while also ensuring that the structural integrity and support of the stairs are not compromised.

In aviation operations, it is critical to optimize the boarding and deplaning process as much as possible, and having four passengers utilize the MCD stairs at once supports that efficiency. The answer reflects an understanding of both practical usage and safety in aircraft operations.