What is an AGL foundation?
The buried concrete base that holds elevated lights, signs and PAPI units in place. It is poured by the civil team, but everything above it depends on its position and bolts.
An AGL foundation is a buried base, usually reinforced concrete, that carries an elevated light, sign, PAPI unit or approach-light structure. It holds anchor bolts that the equipment fixes to, and a conduit that brings the cable up through the base to the equipment.
It is a civil interface because it is excavated, reinforced and poured with the civil works. Its position, level, orientation, anchor-bolt layout, conduit entry and sub-base must be agreed with the AGL team before the concrete cures, because errors are hard to correct afterwards.
Concrete base carrying equipment that stands above ground, such as signs, PAPI units and masts.
Buried housing for inset or shallow-mounted lights and their connections.
Approach Lighting Mast Foundation
An approach lighting mast stands on an AGL foundation: a buried base, usually reinforced concrete, that carries the approach-light structure. It holds the anchor bolts the equipment fixes to and a conduit that brings the cable up to the equipment. Its position, level, orientation, anchor-bolt layout and conduit entry must be agreed with the AGL team before the concrete cures. Equipment connects through a frangible coupling where required. See Approach-Light Structures and Approach-Light Foundations.
Frequently Asked Questions
Q1What is a foundation in airfield ground lighting?
A buried base, usually concrete, that supports an AGL structure above ground such as an elevated light, sign, PAPI unit or approach-light mast. It carries the equipment's weight and resists wind and other loads.
Q2Why is a foundation a civil interface?
It is excavated, reinforced and poured as civil works. Its position, level, orientation, anchor bolts and conduit entry must be set to the AGL layout, and the civil team and AGL team must agree them before the concrete cures.
Q3How is a foundation different from a base can?
A base can is a buried housing that carries an inset or shallow-mounted light and its connections. A foundation is a concrete base that supports an equipment structure standing above ground.
Q4What does a foundation contain?
Typically a concrete block on a compacted sub-base, reinforcement, anchor bolts or a cast-in mounting set to a template, and a conduit that brings cable up through the base to the equipment.
Q5Why does anchor-bolt position matter?
The equipment bolts directly to them, so errors in position, height or orientation are hard to correct after the concrete cures. A template holds the bolts while the foundation is poured.
Q6Where are the requirements defined?
FAA AC 150/5340-30 covers design and installation details for airport visual aids, AC 150/5370-10 covers construction items such as concrete and conduit, and AC 150/5345-42 covers light bases and accessories. ICAO Annex 14 Volume I sets the frangibility requirement for elevated equipment, and ICAO Aerodrome Design Manual (Doc 9157) Part 5 covers electrical systems. Confirm against the current edition and the manufacturer's data.
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