Figure 33. Dirt Packed against base of cone.
(4) Obstacle Lights Installation.
the mast should be as close to the obstacle as possible,
and located so that the obstacle is between the mast and
(a) In noncombat areas where obstacle lights are
immediately adjacent to the obstacle, it should be placed
needed near the ends of the runway, the must be above
so that the top of the mast is above the obstacle, and a
the elevation of the obstacle; TM 330, paragraph 12-20
line drawn from the top of the mast to the highest point
discusses the subject of obstruction lighting. The mast
on the obstacle forms an angle with the horizontal which
set supplied in the supplementary set is used for this
is no less than the maximum glide angle for the airfield.
purpose. The mast set contains four telescoping masts,
In addition, the line of sight drawn from the threshold
each of which 9 feet, 5 inches (2.87 meters) long, when
lights to the obstacle light on the mast should clear the
telescope and 41 feet (12.5 meters) long when fully
(b) Where possible, the obstacle light should be
mounted on top of the obstacle. Otherwise
Figure 34. Position of obstacle light mast with respect to obstacle.