What is the maximum negative differential pressure in psi?

What is the maximum negative differential pressure in psi?

• A. -0.5 psi
• B. -1.0 psi
• C. 0.0 psi
• D. -0.25 psi

Answer: (A)

Differential pressure is the difference between cabin pressure and outside air pressure, and the airplane is certified to tolerate limits in both directions. The negative limit is the most the cabin can be below outside pressure without risking structural damage. For this airplane, that negative limit is -0.5 psi, meaning the cabin can be up to 0.5 psi lower than outside pressure but not more. That makes -0.5 psi the maximum negative differential. The other options either exceed the certified limit or are less than the maximum negative value, so they aren't the correct bound.

Differential pressure is the difference between cabin pressure and outside air pressure, and the airplane is certified to tolerate limits in both directions. The negative limit is the most the cabin can be below outside pressure without risking structural damage. For this airplane, that negative limit is -0.5 psi, meaning the cabin can be up to 0.5 psi lower than outside pressure but not more. That makes -0.5 psi the maximum negative differential. The other options either exceed the certified limit or are less than the maximum negative value, so they aren't the correct bound.