Why is the cabin slightly pressurized on the ground before takeoff?

• A. To minimize pressurization bumps felt in ears on takeoff
• B. To keep the cabin at sea level
• C. To ensure immediate oxygen flow on takeoff
• D. To reduce fuel consumption

Answer: (A)

This is about smoothing pressure changes inside the cabin to reduce ear discomfort during takeoff. The cabin is kept slightly pressurized while on the ground, so when you lift off and begin the climb, the transition to higher cabin altitude isn’t as abrupt. That small pre-pressurization means the ears don’t have to cope with a large sudden pressure difference right at liftoff, reducing the pops or fullness you feel. It’s about comfort and a smoother transition into the climb, not about keeping sea level pressure, providing immediate oxygen, or saving fuel.