What is sign installation?
Putting an airfield sign where the pilot can read it — set out at its surveyed set-back, fixed on a level foundation through frangible legs, connected to its cable and earth, then tested lit against the signage plan.
Sign installation is setting an airfield sign at its designed position, with its face square to the approaching pilot, and fixing it on a level foundation through frangible legs at the design height. The sign’s cable is then connected to its transformer and the sign circuit, the sign is earthed and bonded, and it is closed, sealed and tested lit.
A sign that is in the wrong place, turned, or carrying the wrong legend can send an aircraft the wrong way, and one that stands too close to the pavement is more likely to be struck. Set the position out from the design and a survey rather than by eye, keep the frangible break points clear of added bracing, grout or tight cable, and check the legend against the signage plan before leaving. See Sign Alignment and Sign Visibility for the aim and the readability. Treat the circuit as live until it has been isolated, locked out and proved dead.
- Isolate. Switch off, lock out and prove the circuit dead before any work.
- Set out. Mark the position at the designed set-back and fix the direction of the face from the plan.
- Prepare the foundation. Locate existing cables before digging, then set it level, with the cable entry in place and the earth provision made.
- Mount the sign. Fix it on its frangible legs at the design height and tighten to the specified torque.
- Connect. Make the cable, transformer and earth connections, seal them and close the sign.
- Test and record. Check it lights, the legend matches the plan and the face is square and clear, then clear all tools and log it.
Frequently Asked Questions
Q1What is sign installation in AGL construction?
Placing an airfield sign at its designed position and fixing it so it can be read and is safe. It covers setting out the position, preparing a level foundation, mounting the sign on its frangible legs at the design height, connecting its cable and earth, then testing it lit and checking the legend.
Q2Why are the set-back and face direction set out so carefully?
A sign must sit the designed distance from the pavement edge and face the approaching pilot squarely. Too close, and it risks being struck. Too far, or turned, and it is harder to read. Set the position from the design drawings and a survey, not by eye.
Q3How is a sign mounted so that it stays frangible?
Fix it on its manufacturer’s frangible legs or couplings at the design height, with the break points where the design puts them. Do not add bracing, grout or fixings that bridge the break points, and keep the cable slack. See Frangible Mounting (Installation).
Q4What is connected when a sign is installed?
The sign’s cable is connected to its transformer and the sign circuit, and the sign is earthed and bonded as the design requires. Make the connections as the manufacturer specifies, seal them, and close and seal the sign. Treat the circuit as live until it has been isolated, locked out and proved dead.
Q5What is checked before leaving a new sign?
Check that the sign lights and that its legend and arrows match the signage plan. Check that it is square to the approach, at the design height and set-back, clean and not obstructed, and that the fixings are at the specified torque. Remove all tools and debris from the airfield and record the result.
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