2. What are the OPC assumptions in calculating Approx Stop Margin?
Answer: Touchdown occurs no later than 1500 feet from the usable end of the runway. Selecting reverse thrust within 2 seconds after touchdown and attaining the planned reverse thrust level within 8 seconds after touchdown. Speedbrake deployment, thrust at idle, runway condition, and proper winds programmed. The OPC then includes a 15 percent additional safety factor on the total calculated landing distance. The Min(2), Med(3), and Max(M) values are calculated using the deceleration rates for auto brake settings 2, 3, and Max, respectively.