c) Semiannual checks
(1) Check the interior of control panel and flasher cabinets for cleanliness and
(2) Check electrical contacts and connections to ensure tightness.
(3) Check and adjust alignment and elevation of light units. For omnidirectional
units, only the elevation is checked. For unidirectional REILs, check alignment and elevation
using the following tools:
(a) A plywood triangle cut to angles of 15 degrees, 80 degrees,. and 85 degrees.
(b) A 4 inch-line level.
(4) The procedure to align the unidirectional REIL is as follows:
(a) To check the 15 degree toe-out, hold the triangle horizontally against the
face with the 15 degree angle pointed toward the other light unit. By aligning the outside edge of
the triangle to point at the opposite light unit, 15 degree toe-out is achieved.
(b) To attain the 10 degree vertical aiming, the 80 degree angle is placed
against the flat portion of the REIL face with the 15 degree point-down. When the line level
shows the upper edge of the triangle level, the REIL is 10 degrees up from the horizontal (see
(5) Check baffles, if used on REIL. Where baffles are installed, the light units
should be aimed at an angle of 3 degrees vertical and 10 degrees toed out. The louvers should be
sloped down 10 degrees toward the runway and down 5 degrees toward the approaching aircraft.
The louvers should be painted black to lower the reflected light.
d) Annual checks
(1) Make a careful inspection of all power distribution equipment and protective
devices at terminal pole and lights.
(2) Check insulation resistance of power cables (refer to par. 4.7).
(3) Check the ground resistance at the terminal pole and each light fixture.
(4) Service timer motor and contacts (if used).
(5) Repaint as required.