The Maximum negative differential pressure is which value?

The Maximum negative differential pressure is which value?

• A. -0.5 PSI
• B. -1.0 PSI
• C. 0.0 PSI
• D. -0.2 PSI

Answer: (A)

The key idea is how much pressure difference the fuselage can safely have when cabin pressure is compared to outside pressure. This difference is cabin pressure minus outside pressure, called differential pressure. A negative differential means the cabin is lower than the outside air. The aircraft is designed to handle a much larger positive differential than negative, so the negative side is tightly limited to prevent overstressing the fuselage and seals during depressurization events. For the CRJ-550, the limit on how negative that difference can be is -0.5 psi. That makes -0.5 psi the maximum negative differential because going any more negative (like -1.0 psi) would exceed certification and could compromise structural integrity or seal performance. The other options are either not as negative or exceed the allowable limit, so -0.5 psi is the correct value.

The key idea is how much pressure difference the fuselage can safely have when cabin pressure is compared to outside pressure. This difference is cabin pressure minus outside pressure, called differential pressure. A negative differential means the cabin is lower than the outside air. The aircraft is designed to handle a much larger positive differential than negative, so the negative side is tightly limited to prevent overstressing the fuselage and seals during depressurization events. For the CRJ-550, the limit on how negative that difference can be is -0.5 psi. That makes -0.5 psi the maximum negative differential because going any more negative (like -1.0 psi) would exceed certification and could compromise structural integrity or seal performance. The other options are either not as negative or exceed the allowable limit, so -0.5 psi is the correct value.