(c)
The resulting gap on the outside of the turn is closed by appropriate radii equal to the distance from the WP center to the edge of the primary or secondary abeam the TWP.
(4)
When the DTA point prior to the WP occurs during the splaying of the obstacle clearance area boundaries, (i.e., inside the area where the splay is incomplete):
(a)
Locate a point A' on the edge of the primary area at the DTA distance, measured parallel to the course following the plotted position of the WP after completing the turn. Construct the primary boundary area by connecting point A with A'. See appendix 1, figure 10.
(b)
Locate point B on the edge of the secondary area abeam point A. Locate point B' on the edge of the secondary area abeam point A'. Construct the secondary area boundary by connecting point B with B'. See appendix 1, figure 10.
(c)
For turns less than or equal to 75°, the resulting gap on the outside boundaries of the turn is closed by appropriate radii equal to the distance from the plotted of the TWP to the edge of the primary or secondary area abeam the TWP. See appendix 1, figure 11a.
(d)
For turns greater than 75°, after the turn, locate A' on edge of primary area at the DTA distance measured from the latest point of the WP displacement area. The resulting gap on the outside boundaries of the turn is closed by radii equal to 2NM for the primary area and 3NM for the secondary. The succeeding segment’s primary and secondary area boundary on the outside of the turn expand to 2NM and 1NM respectively. When the width of the primary area at the TWP has not reached 2NM, extend the primary and secondary boundaries of the preceding segment beyond the TWP until the primary area boundary intersects a 2 NM arc centered on the TWP. Continue the secondary area boundary until it intersects a 3 NM arc centered on the TWP. See figure 11b.
10. Departure Altitude. Establish a departure altitude which is the highest altitude of:
a.
When joining an existing airway:
(1)
A level surface evaluation. (see paragraph 11f)
(2)
The appropriate MEA or MCA for the direction of flight.
b.
Off airway termination:
(1)
A level surface evaluation.
(2)
Altitude where radar service can be provided.
c.
An air traffic control requirement.
11. OBSTACLE EVALUATION. The area considered for obstacle evaluation begins at the beginning of the departure area, and ends at a point or WP/fix/NAVAID defining the end of the departure. See paragraph 13. The maximum required obstacle clearance (ROC) for level flight is 1,000 feet in non-mountainous areas and 2,000 feet in designated mountainous areas, except when Order 8260.3B, paragraph 1720, is applied. Do not compute a climb gradient above an altitude which satisfies these ROC's.
a.
Primary Area. No obstacle shall penetrate the OIS which begins at the DER and rises from DER elevation in the direction of flight. The OIS rises along the shortest distance in the primary area from its beginning to the obstacle. For turns evaluate obstacles on the turning side of the initial climb area by measuring back the shortest distance to the DER. See appendix 1, figures 2 and 17.
b.
Secondary Area. No obstacle shall penetrate a 12:1 OIS which rises from the edge of the primary area perpendicular to the segment course. In a turn expansion area, the 12:1 OIS rises perpendicular to the edge of the primary area. See appendix 1, figures 2 and 17. Determine the height of an equivalent obstacle on the edge of the primary area, then evaluate the equivalent obstacle relative to the 40:1 OIS, at that point.
Example: A 9,840-foot MSL obstacle is located in the secondary area, 2,700' from the edge of the primary area.
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