During taxi and takeoff, what must the cabin differential pressure not exceed?

The cabin differential pressure during taxi and takeoff must not exceed 0.1 PSI. This limitation is crucial for ensuring structural integrity and passenger safety. Maintaining cabin pressure at or below this threshold helps to prevent undue stress on the aircraft structure, which could lead to potential failure or compromise of the airframe under varying external pressures during these critical phases of flight.

By limiting the differential pressure, the aircraft can ensure that the pressure differential does not cause any issues with the aircraft systems or passenger comfort prior to departure. The low threshold during taxi and takeoff helps manage the transition from ground atmospheric pressure to the increasing pressure experienced during the climb phase as the aircraft ascends to cruising altitude. Overall, this limit is an important safety measure in flight operations.