c) Vault Security. The vault should be kept locked, except during maintenance, to
keep unauthorized personnel out. Contact with the high-voltage buses in an airport lighting vault
is nearly always fatal. Only authorized personnel, experienced in the hazards of high voltage,
should be allowed in the vault.
d) High-Voltage Warning Signs. High-voltage warning signs, as described in par. 2.5,
should be prominently displayed at appropriate locations.
e) Safety Board. Safety boards, as described in par. 2.4, should be installed in the
Runway and Taxiway Edge Lighting Systems
Preventive Maintenance Inspection Procedures. To perform the PMIs contained in
Table 11, proceed as follows:
a) Daily checks
(1) Perform a visual inspection of the system at twilight or night each day. This
inspection consists of a driving patrol to visually check for dimly burning bulbs, burned-out
lamps, and fixtures out of alignment. The locations of such fixtures should be recorded and
corrections should be made as soon as possible. Replace dimly burning lamps and burned-out
lamps when the system is deactivated.
(2) Check lenses for cleanliness and clean as required.
b) Monthly checks
(1) Check the orientation of all lenses. This check should be made by viewing the
lights at night. Misaligned light units will appear dimmer or brighter than those that are properly
aligned. The lenses may get out of adjustment when replacing lamps or when mowers and other
vehicles strike the elevated lights.
(2) Straighten, level, and align all lighting units that have been knocked out of
(3) Check lamp sockets for cleanliness and good electrical connections. If
moisture is present, replace the fixture gasket.
(4) Inspect and clean the weep hole in the frangible coupling of stake-mounted
c) Semiannual checks
(1) Check the ground elevation around lighting fixtures. The frangible point
should be approximately 1 inch (2.5 cm) above the ground elevation. Grade around the fixture
where necessary to maintain this fixture/grade relationship. Also, maintain the elevation of all
lights the same height above the runway/taxiway pavement edge. The elevation should be
checked more frequently during times of frequent freeze/thaw cycles. The height of the lights
should not exceed 14 inches (35 cm) when located within 5 feet (1.5 m) of the runway or
taxiway edge. In snow regions, where the lights are located beyond 5 feet (1.5 m) from the
runway or taxiway edge, the lights may be raised 2 inches (5 cm) for each foot beyond the 5 foot
(1.5 m) point. At the 10 foot (3 m) position, the lights may have a maximum height of 30 inches
(75 cm). The increase in height is permitted only if any overhanging part of an aircraft expected