§29.1387 Position light system dihedral angles

(a) Except as provi ded i n sub-paragraph (e), each forward and rear position light m ust, as installed, show unbroken l ight within the dihedral angles described in this paragraph. (b) Dihedral angle L (left) is form ed by two intersecting vertical planes, the first parallel to the longitudinal axis of t he rotorcraft, and the other at 110° to t he l eft of t he fi rst, as vi ewed when looking forward along the longitudinal axis. (c) Dihedral angle R (ri ght) is formed by two intersecting vertical planes, the first parallel to the longitudinal axis of t he rotorcraft, and the other at 110° to the right of t he fi rst, as vi ewed when looking forward along the longitudinal axis. (d) Dihedral angle A (a ft) is form ed by two intersecting vertical planes making angl es of 70° to the rig ht an d to th e left, resp ectively, to a vertical plane passi ng t hrough t he l ongitudinal axis, as vi ewed when l ooking aft al ong the longitudinal axis. (e) If t he rear posi tion l ight, when mounted as far aft as practicable in accordance with CS 29.1385(c), cannot show unbroken l ight within dihedral angle A (as defined in sub-paragraph (d)), a solid an gle o r an gles o f o bstructed v isibility totalling not m ore t han 0.04 steradians is allowable within that dihedral an gle, if su ch so lid angle is with in a co ne w hose apex is at the rear position l ight and whose el ements m ake an angle of 30° with a vertical line passing through the rear position light.