The purpose Braking Action information and how it is used
Takeoff Planning
The planning processes before takeoff also involve a Flight Dispatch procedure. Simply put, for the takeoff part, it is a calculation to assure that the aircraft can stop before the end of runway in event of a rejected takeoff at high speed. The “GO / NO-GO” point is a speed threshold based on an aircraft’s performance configuration, and any attempt to stop after will likely result in an overrun.
A few of the parameters used to perform this flight operational calculation are aircraft weight/payload and the runway surface conditions.
One Engine Inoperative During Takeoff
Flight operational calculation always take into consideration “worst scenario.” One of these involves engine failure during takeoff. Aircraft can operate on one engine but has certain restriction. A required return to airport would involve heavier weight and higher landing speed for pilots to keep the aircraft under control. Such a landing will result in a longer landing- and stopping distance. This distance must be calculated as part of the flight dispatch procedure and involves the assessment of runway surface conditions.
Landing Distance at Destination
Before a flight, the flight dispatch procedure must assure that the aircraft can land at its destination airport, as well as its assigned alternative (alternate) airport in event restrictions at destination airport. Such planning and assessments for destination airport and its alternative involve knowledge about runway surface conditions.
Enroute Monitoring
Weather changes and forecasting in form of “Now-Cast,” the short-term change of local weather conditions, are more difficult to predict than area macro weather. Therefore, enroute monitoring of weather and runway surface conditions at destination- and alternate airport are essential and part of the critical “situational awareness.” Changes to assumptions laid to ground for the initial flight dispatch require renewed calculations. Changes to runway surface conditions is one such element that require an updated landing distance assessment.
