What could indicate a malfunction in the cabin pressure system based on the altitude readouts?

A malfunction in the cabin pressure system can be indicated by the outflow valve not closing at designated altitudes. The outflow valve is a critical component that regulates cabin pressure by allowing air to escape from the cabin at a controlled rate. If the valve does not close as it should, the cabin may not maintain the proper pressure for the altitude in which the aircraft is flying. This can lead to either inadequate cabin pressure or an excessive pressure differential, potentially resulting in discomfort for the passengers or even a dangerous situation.

Stable readings at high altitude, automatic oxygen flow at low altitude, and consistent PSI readings across cabin pressure may not necessarily indicate a malfunction. For example, stable altitude readings could simply reflect that the aircraft is performing normally at high altitude. Automatic oxygen flow at low altitude typically serves as a safety mechanism and would not necessarily point to a malfunction, assuming that low altitude is outside of normal operation parameters. Consistent PSI readings across cabin pressure could imply a healthy pressure situation if within the expected ranges. Therefore, the specific failure of the outflow valve to close at the proper altitudes is a clear and direct indication of a malfunction in the cabin pressure system.