If there are 82 or fewer cabin occupants, what is the maximum altitude for single pack operation?

In the context of single pack operation on the Endeavor Air CRJ 900, the correct maximum altitude of 31,000 feet for operation with 82 or fewer cabin occupants is established to maintain cabin pressure within safe limits.

When the aircraft operates with only one air conditioning pack, it can adequately manage cabin pressure and temperature provided that the number of passengers or occupants does not exceed certain thresholds. The specified altitude of 31,000 feet is essentially the upper limit where the aircraft can still ensure a safe and controlled environment without compromising passenger comfort and safety.

Beyond this altitude, while operating on a single pack, there may be limitations in maintaining proper circulating air and pressurization, especially with a larger number of cabin occupants. Thus, the threshold of 82 cabin occupants is set in conjunction with the maximum altitude to ensure that the aircraft's systems function optimally under these conditions.