What is the maximum differential overpressure?

What is the maximum differential overpressure?

• A. 10.0
• B. 10.3
• C. 11.0
• D. 9.0

Answer: (B)

The maximum differential overpressure is the greatest pressure difference the pressurization system and the aircraft structure are designed to withstand between cabin pressure and outside ambient pressure. This limit is set by structural design and safety relief devices to prevent damage to the fuselage and doors if the cabin were pressurized beyond safe limits. In this airplane, manufacturer specifications and the pressurization system's relief settings establish 10.3 psi as the upper limit. The relief valves and controls are sized so that as soon as differential nears this value, excess pressure is vented to protect the airframe, keeping cabin pressure within certified bounds. That’s why 10.3 psi is the correct maximum. The other values are either below the published limit or exceed it. 9.0 psi is a typical operating differential, not the maximum; 10.0 psi is close but not the stated limit; 11.0 psi would surpass the allowed maximum and could cause structural risk.

The maximum differential overpressure is the greatest pressure difference the pressurization system and the aircraft structure are designed to withstand between cabin pressure and outside ambient pressure. This limit is set by structural design and safety relief devices to prevent damage to the fuselage and doors if the cabin were pressurized beyond safe limits.

In this airplane, manufacturer specifications and the pressurization system's relief settings establish 10.3 psi as the upper limit. The relief valves and controls are sized so that as soon as differential nears this value, excess pressure is vented to protect the airframe, keeping cabin pressure within certified bounds. That’s why 10.3 psi is the correct maximum.

The other values are either below the published limit or exceed it. 9.0 psi is a typical operating differential, not the maximum; 10.0 psi is close but not the stated limit; 11.0 psi would surpass the allowed maximum and could cause structural risk.