to use the runway or taxiway could clear the light by at least 6 inches (15 cm) when the plane's
main landing gear is located on any part of the runway or taxiway.
(2) Check light bases and housings for evidence of moisture penetration. Check
(3) Check fixtures, bases, and housing for corrosion, rust and peeling paint.
d) Annual checks
(1) Check each light fixture carefully for cracking, corrosion, or shorts.
(2) Clean the contacts and ensure that lamp fits firmly into receptacle.
(3) Check condition of all connections.
(4) Check runway cable insulation (refer to par. 4.7). Check the insulation after
(5) Check all gaskets on a leaky light unit and replace with new rubber gaskets.
e) Unscheduled Maintenance. Remove snow from around the lighting fixtures as
soon as possible after a snowfall so the light fixtures are not obscured. If heavy snowfalls are
predicted, red flags or sticks of sufficient length should be planted adjacent to the edge lights to
mark their location. The flags will facilitate snow removal and will lessen the damage to fixtures
by snow removal equipment.
Maintenance Procedures. The following paragraphs discuss general maintenance
procedures for the runway and taxiway units that are not functioning, and also discuss
troubleshooting of series circuits.
a) Lamp Replacement. With the lights operating, make a visual check to positively
identify the lighting unit or units that are not functioning.
De-energize the circuit and lock out the circuit or regulator so that the circuit
cannot be energized from the remote lighting panel or other means before starting
work on the lights. Remove S-1 switch cutouts if present.
(1) Turn off the lights and lock out circuits. Install safety warning signs (refer to
par. 2.5) at appropriate locations.