For single pack operation, what is the maximum altitude if there are more than 82 cabin occupants?

In the context of aircraft operations, particularly for the CRJ 900, single pack operation refers to running only one of the two available air conditioning packs to manage cabin temperature and pressurization. When more than 82 occupants are present in the cabin, it becomes crucial to limit the altitude to ensure passenger comfort and safety due to the reduced capability of a single pack to adequately condition the cabin air.

The maximum altitude restriction of 25,000 feet for single pack operation with over 82 occupants is established to maintain safe and comfortable conditions. At higher altitudes, the air becomes thinner, reducing the efficiency of the pack. This can lead to inadequate cabin pressure and temperature control, which could compromise the well-being of passengers.

Setting the limit at 25,000 feet ensures that while operating with only one pack, the aircraft can still provide a safe environment for the crew and passengers under the specified conditions. Thus, that altitude is a critical operational limitation designed to enhance safety in line with the number of occupants on board.