What is PAPI work safety?

Working on a PAPI beside a runway without harm: get clearance, isolate the circuit, leave the aimed units undisturbed, and check aim and output before hand back.

PAPI WORK SAFETY · CLEAR, ISOLATE, WORK, CHECK 1CLEARClearance, marked area 2ISOLATECircuit off, locked, tagged 3WORKAimed units not disturbed 4CHECKAim, output, hand back PLAN VIEW · PAPI UNITS BESIDE A RUNWAY RUNWAY · STATUS SET BY ATC CCR OFF · LOCKED · TAGGED DO NOT KNOCK OR SHIFT AIMED UNITS PAPI UNITS · FRANGIBLE MOUNTS MARKED WORK AREA ESCORTED ROUTE ATC / AIRPORT OPS CLEARANCE Work area agreed · told when complete 1 2 3 4 AIM AND OUTPUT CHECKED · TOOLS COUNTED · AREA CLEAR · ISOLATION LIFTED · ATC TOLD SCHEMATIC · CLEARANCE, ISOLATION AND POST-WORK CHECKS FOLLOW THE AIRPORT’S PERMIT-TO-WORK PROCEDURE
aim / live-circuit hazard
PAPI units / work area
cleared / isolated / checked
The Fact Safety principle

A PAPI (precision approach path indicator) is a row of light units beside the runway that shows pilots whether they are on the glide path, through the red and white each unit displays. Because the units sit close to active pavements, the work needs ATC or airport operations clearance, a marked work area, an escorted route for vehicles, and a report back when the work is complete.

Each unit is aimed to a set angle, so a knock or shift can show a pilot the wrong glide path. Units and their frangible mounts are never used as steps or handholds, and a disturbed unit is reported and re-checked by trained people. The circuit is isolated at the CCR, locked, tagged and proved dead, tools are counted, and nobody looks into a lit unit. Before hand back the aim and light output are checked and any checks the airport requires are done.

HazardsAircraft, live circuit, disturbed aim
ClearanceATC / ops, marked work area
IsolationAt the CCR, locked and tagged
UnitsFrangible mounts, aimed to a set angle
NeverKnock, shift or climb on a unit
VehiclesEscorted route only
After workAim and output checked, ATC told
ReferenceAirport procedures and permit to work; ICAO Annex 14 for PAPI background; manufacturer aiming instructions
Awareness schematic only, not a working procedure. Clearance, closure arrangements, isolation, aiming and checking, any flight check after work, and who may carry them out, come from the airport’s procedures, the manufacturer and your employer’s permit to work.
Entry 16 · Transformer-pit safety Entry 18 · Approach-light work safety

Frequently Asked Questions

Q1What is PAPI work safety?

It is the set of habits for working on a precision approach path indicator (PAPI) safely. PAPI units sit beside the runway and show pilots whether they are on the glide path, so the work needs airport clearance, a marked work area, an isolated circuit and great care not to disturb the aimed units.

Q2Why is clearance needed before working beside a runway?

Aircraft use the runway and its surroundings, and PAPI units are close to the pavement. Airport operations or ATC must agree the work, the work area and how people and vehicles get there, and must be told when it is finished. The airport’s permit to work sets the details.

Q3Why must PAPI units not be knocked or shifted?

Each unit is aimed to a set angle, and the red and white that a pilot sees depends on it. A unit that has been moved can show a wrong glide path. If a unit may have been disturbed, it is reported and checked by trained people rather than guessed back into place.

Q4How is the circuit made safe?

Like any series circuit, it is isolated at the CCR, locked and tagged, and proved dead before work starts, as the site’s permit to work requires. Opening a live series loop can create a dangerous voltage.

Q5What else should be controlled around a PAPI unit?

Vehicles stay on the escorted route and inside the marked area, units and their frangible mounts are not used as steps or handholds, tools are counted out and in, and nothing is left behind as FOD. A lit unit is also very bright, so nobody looks into its beam.

Q6What happens before the area is handed back?

The aim and light output are checked by trained people, any checks the airport requires after work are done, tools are counted back and the area is cleared. The isolation is then lifted by its owner and the airport is told the work is complete.

Precision AGL Academy

See It. Understand It. Then Learn How to Engineer It.

Recognising an AGL system visually is the first step. The next step is knowing how to design, install, test, commission and maintain them correctly.

Build Practical AGL Engineering Skills

Go deeper with structured training from Precision AGL Academy, covering:

AGL Fundamentals Design & Electrical Engineering Approach Lighting Photometry Installation & Commissioning Maintenance & Troubleshooting

Learn how each light, sign and circuit works as part of a complete airport lighting system, not just as an isolated diagram.

See. Understand. Apply. Engineer.