Method One Drift Down Analysis
For the Method One Analysis, we plot the aircraft trajectory by the optimal route calculations provided by flight planning organizations. We also calculate the fuel burn for approximate aircraft weight loss across the flight path. Obstacles are identified and their distances are calculated from the reference location. The analysis can be calculated with either actual or forecasted atmospheric conditions. Based on temperature, pressure, obstacle height, and safety margins, we can calculate the maximum weight for obstacle clearance. This method can be limiting, but it provides needed enroute performance calculations necessary for flights over mountainous terrain.