What occurs during the maximum differential pressure limit?

During the maximum differential pressure limit, pressure relief valves may open to protect the structure of the aircraft and ensure safety. These valves are designed to release excess pressure to prevent potential damage to the aircraft's fuselage and systems. This is a crucial safety mechanism that allows the aircraft to maintain structural integrity under varying pressure conditions, especially during ascent and descent.

Maintaining cabin pressure is an important function of the aircraft, but it is not directly the event that occurs at the maximum differential pressure limit. Increased oxygen flow is related to altitude but doesn't automatically occur due to differential pressure limits. Emergency landing procedures might be activated in response to critical situations but are not a standard outcome of reaching maximum differential pressure. Thus, the opening of pressure relief valves is the definitive action that directly relates to managing pressure within safe limits.