Definition
The degree to which an aircraft's wheel brakes are able to slow the aircraft during the landing roll or rejected takeoff, determined by how much friction the tires can develop against the runway surface. It depends on weight on the wheels, tire condition, and runway surface conditions such as water, snow, ice, or contamination. Spoilers improve braking effectiveness after touchdown by killing wing lift and transferring more aircraft weight onto the wheels.
Plain English
How well the brakes can actually slow the airplane down on a given runway. Good braking effectiveness means the brakes bite well and the airplane stops quickly. Poor braking effectiveness means the wheels slide and the airplane takes much longer to stop.
Context Anchor
Seen in landing discussions, especially when spoilers deploy after touchdown to help the wheels press firmly onto the runway.
Why Pilots Care
Directly determines required landing distance and the safety margin available on the runway.
Grounding Statement
After touchdown, the brakes work best when the tires are firmly on the runway instead of lightly skimming while the wings still carry some weight.
Intuition Check
Do not read this as simply “pressing the brakes harder.” Braking effectiveness means how well the airplane actually slows, which depends on tire grip, runway condition, and how much weight is on the wheels.
Example Sentence 1
After touchdown the spoilers deployed, dumping lift onto the wheels and improving braking effectiveness on the wet runway.
Example Sentence 2
Lower braking effectiveness forced the crew to use more runway than planned during rollout.