Definition
A pilot or airport report indicating that braking effectiveness on a runway or taxiway surface is reduced from normal but still usable. 'Fair' is the middle category in the standard braking action scale, which runs from good, to good-to-medium, medium, medium-to-poor, poor, and nil. A report of fair means deceleration and directional control are noticeably degraded compared to a dry runway, and the pilot should expect longer stopping distances and reduced ability to handle crosswinds.
Plain English
The runway is slippery enough that stopping and steering will take more room and effort than normal, but the surface is still safe to use with care.
Context Anchor
Seen in runway condition reports, NOTAMs, or airport advisories when a runway may be wet, icy, snowy, or otherwise slippery.
Derivation
Braking action' simply describes how well the tires can slow and steer the aircraft on the surface. 'Fair' is used here in its older sense of 'middling' or 'moderate' — not 'good,' not 'poor,' but somewhere in between. It is the same sense found in phrases like 'fair weather' meaning acceptable but not ideal.
Why Pilots Care
Pilots use this information to decide whether a runway is safe for landing, especially when the surface is wet or contaminated, directly affecting go or no-go decisions and landing distance calculations.
Intuition Check
Do not read “fair” as “good” or “normal.” Here it means braking is usable, but reduced.
Example Sentence 1
Tower reported BA FAIR on Runway 27, so we added a margin to our landing distance and planned to use the full length.
Example Sentence 2
With braking action fair due to light snow, the pilot increased the calculated landing distance.