Definition
A runway surface condition report indicating that no measurable braking effectiveness is available — wheel brakes will not slow the aircraft predictably during landing rollout or rejected takeoff. When BA NIL is reported, the runway is considered unusable for normal operations by most operators, and many regulators and air carriers prohibit takeoff or landing on a runway with this reported condition.
Plain English
The runway is so slippery that the brakes basically won't work. Pilots don't try to land or take off on a runway in this condition.
Context Anchor
Seen in NOTAMs, airport condition reports, and winter or contaminated-runway information before taxi, takeoff, or landing.
Derivation
‘Nil’ comes from the Latin nihil, meaning ‘nothing.’ In braking action reports it carries that strict sense — not ‘poor’ or ‘almost none,’ but effectively zero usable braking.
Why Pilots Care
A nil report signals that landing is unsafe and diversion or delay is required to avoid loss of directional control.
Grounding Statement
Picture touching down on smooth ice: pressing the brakes may do almost nothing, and the airplane may continue sliding.
Intuition Check
Nil does not mean “poor” or “unknown.” In this report, it means essentially no usable braking has been reported.
Example Sentence 1
After the freezing rain, the tower reported BA NIL on Runway 27, and the crew diverted to an alternate.
Example Sentence 2
Heavy ice produced BA NIL conditions and the flight held until the surface improved.