Document ID: chunk:federal_register_of_legislation:F2005B01529:body:0:p2
Version: federal_register_of_legislation:F2005B01529
Segment Type: other
Provision Reference: 
Character Range: 2504–5038

route segment is determined by any other means, the effective area of the route segment is the area that comprises:
 (a) the navigation tolerance area of the route segment, determined in accordance with paragraph 5.2; and
 (b) a 5-mile wide area surrounding the navigation tolerance area.

Calculating the height of the corrected highest terrain
4.1 The height of the corrected highest terrain in the effective area of a route segment is the higher of the following:
 (a) the highest spot height in the effective area plus 360 feet;
 (b) the height of the highest contour in the effective area as shown on an aeronautical topographical chart  plus the height equal to the height between 2 successive contours as shown on the chart plus 360 feet.

Calculating the navigation tolerance area:
5.1 If the LSALT for a route segment is determined by reference to Grid LSALTs, the navigation tolerance area of the route segment is the area of the earth's surface ascertained by applying on either side of the planned track the navigation error allowance appropriate to the navigation aids, system or method used for the navigation of the aircraft.

5.2 If paragraph 5.1 does not apply, the navigation tolerance area of a route segment is the area of the earth's surface bounded by 2 imaginary lines that:
 (a) start at the beginning of the route segment and diverge, one on each side, from the planned track:
 (i) if a navigation aid is used at the beginning of the route segment—at an angle of 10.3; and
 (ii) if a navigation aid is not used at the beginning of the route segment—at an angle of 15; and
 (b) if an area navigation system is being used—continue until:
 (i) each line reaches a point abeam the end of the route segment; or
 (ii) each line reaches a point 30 miles abeam the planned track; or
 (iii) each line reaches a point in the rated coverage area of the navigation aid at the end of the route segment from which a straight line drawn to the end of the route segment would converge with the planned track at an angle of not less than 10.3;
  whichever happens first; and
 (c) if an area navigation system is not being used—continue until:
 (i) each line reaches a point abeam the end of the route segment; or
 (ii) each line reaches a point 50 miles abeam the planned track; or
 (iii) each line reaches a point in the rated coverage area of the navigation aid at the end of the route segment from which a straight line drawn to the end of the route segment would converge with the planned track at an angle of not less