Landing Performance
So...here I am, reading my notes about performance, and came across something that I am yet to understand.
Limitations for Landing Weight are Runway Length, Approach Climb and Landing Climb.
Runway length, takes into account: Dry runway, Maximum manual braking, "positive" touchdown, speed brakes in use and no reverse, and states the following: "TCH 50', measured from TCH, runway length limitation is demostrated CD (certified distance) + 67%"
What's the 67% used for?