Definition
The numerical runway friction value, established by the airport operator, at which maintenance planning for runway surface treatment should begin. It is above the Minimum Friction Level but below the level of a fully unrestricted surface, and serves as an early warning that the runway's friction characteristics are deteriorating.
Plain English
A friction reading on a runway that tells the airport, 'You need to start planning to fix this surface soon.' The runway is still usable, but it's getting slick enough that maintenance shouldn't be put off.
Context Anchor
Seen in airport runway surface maintenance, runway safety discussions, and reports about measured runway friction.
Derivation
Friction here is the everyday physics term -- the resistance between tire and pavement. 'Maintenance Planning' simply marks this as the trigger point for scheduling work, not the trigger point for restricting operations.
Why Pilots Care
Reaching this level indicates reduced braking effectiveness that can lengthen landing distances and increase the risk of runway excursions.
Analogy
It is like a tire tread warning mark on a car tire. The tire may still be usable, but the mark tells you it is time to plan replacement before performance gets worse.
Grounding Statement
On a wet runway, less pavement grip means the tires may have a harder time slowing the airplane after landing.
Intuition Check
Do not read “planning” as “no problem.” It means maintenance is not yet an emergency, but the runway surface has reached a point where corrective work should be scheduled.
Example Sentence 1
The airport's friction survey showed Runway 27 had dropped to the Maintenance Planning Friction Level, so the operator scheduled rubber removal for the following week.
Example Sentence 2
Pilots noted the Maintenance Planning Friction Level in the airport's surface condition report during preflight planning.