Definition
A runway slope that descends in the direction of takeoff or landing. The runway surface drops in elevation from one end to the other, so an aircraft moving along it is going downhill.
Plain English
The runway slopes downhill in the direction you are rolling. Your starting point is higher than your ending point.
Context Anchor
Seen in runway information and takeoff or landing performance planning, especially when adjusting expected ground roll for runway slope.
Derivation
‘Gradient’ comes from the Latin gradi, meaning ‘to step’ or ‘to walk,’ and refers to the steepness of a slope. ‘Negative’ here simply marks the direction — downhill rather than uphill — relative to the direction of travel.
Why Pilots Care
A negative gradient shortens the takeoff roll but increases landing distance and affects the climb gradient after liftoff.
Grounding Statement
If the runway ahead of the aircraft drops away, the aircraft is operating on a negative gradient.
Intuition Check
Negative does not mean “bad” here. It means the runway slopes downward in the direction being measured.
Example Sentence 1
The pilot noted the runway had a negative gradient and added extra margin to the landing distance calculation.
Example Sentence 2
A negative gradient on the landing runway meant the aircraft would need extra distance to stop after touchdown.