AMC1 CAT.POL.A.415 En-route – OEI    

CAA ORS9 Decision No. 1

ROUTE ANALYSIS

The high terrain or obstacle analysis should be carried out by making a detailed analysis of the route using contour maps of the high terrain, and plotting the highest points within the prescribed corridor width along the route. The next step is to determine whether it is possible to maintain level flight with OEI 1 000 ft above the highest point of the crossing. If this is not possible, or if the associated weight penalties are unacceptable, a drift down procedure must be evaluated, based on engine failure at the most critical point, and must show obstacle clearance during the drift down by at least 2 000 ft. The minimum cruise altitude is determined from the drift down path, taking into account allowances for decision making, and the reduction in the scheduled rate of climb (See Figure 1).

Figure 1

Intersection of the drift down paths