How does the airfield get a lightning warning?

A detector senses lightning near the airfield, and the system alerts the tower and staff before it reaches them.

PLAN VIEW · ZONES ROUND THE AIRFIELDSENSOR TYPES · SITE DEPENDENTDETECTORAIRFIELDSTRIKEINSIDE THE WATCH ZONEINNER · WARNING ZONELIGHTNING CLOSE: STOP WORKOUTER · WATCH ZONESTORM NEAR: PREPAREELECTRIC-FIELD SENSORSENSES CHARGE BUILD-UP BEFORE A STRIKESTRIKE DETECTORSENSES THE PULSE GIVEN OFF BY A STRIKESEVERAL SENSORSTOGETHER THEY CAN FIX A STRIKE POSITIONWIDE-AREA DATASTRIKE DATA FROM A LIGHTNING NETWORKWHAT THE DETECTOR DOESDETECTORSENSES LIGHTNINGPROCESSING UNITCHECKS DISTANCE, ZONEALCMS, TOWERSHOWS THE ALERTSTAFF ON SITESTOP OUTDOOR WORKA STRIKE IN THE WARNING ZONE RAISES THE ALERT, AND OUTDOOR WORK, INCLUDING ON LIGHTING CIRCUITS, STOPSALL CLEAR ONLY AFTER A SET TIME WITH NO STRIKES, AS THE AIRPORT PROCEDURE STATESA DETECTOR WARNS PEOPLE. IT DOES NOT PROTECT EQUIPMENT: THAT IS SURGE PROTECTION AND EARTHINGSCHEMATIC, NOT TO SCALE · ZONE SIZES AND ALL-CLEAR TIME ARE SET BY THE AIRPORT
detector and sensors
watch zone, strike
warning zone
The Fact Airfield sensors

A lightning detector senses lightning near the airfield so that staff can be warned before it reaches them. An electric-field sensor senses the charge build-up before a strike, and a strike detector senses the pulse a strike gives off. Several sensors together can fix the position, and some airports also use wider network data.

A processing unit compares each reading with zones set round the airfield: an outer watch zone and an inner warning zone. The alert goes to the tower display and, where fitted, to the ALCMS, and outdoor work stops, including work on lighting circuits and cables. The all clear is given only after a set time with no strikes, as the airport procedure states. A detector warns people. It does not protect equipment: that is the job of surge protection and earthing.

PurposeWarn of lightning near the airfield
SensorsElectric-field, strike detector, network data
ZonesInner warning, outer watch
Reports toProcessing unit, ALCMS, tower
Used forStopping outdoor work, including on lighting circuits
All clearAfter a set time with no strikes
Fault handlingShow on display, no false all clear
ReferenceAirport procedure and system manufacturer data; IEC TR 62793 (thunderstorm warning systems)
Schematic. Zone sizes, the all-clear time and the sensor types depend on the airport procedure and the system chosen.
Entry 11 · Vehicle detection sensor Entry 13 · Pavement temperature sensor

Frequently Asked Questions

Q1What is a lightning detector?

A sensor system that detects lightning near the airfield and warns staff, so outdoor work can stop before the lightning reaches them. The warning goes to the tower and, where fitted, to the ALCMS.

Q2How does it detect lightning?

An electric-field sensor senses the charge that builds up before a strike. A strike detector senses the pulse a strike gives off, and several sensors together can fix the strike position. Some airports also use data from a wider lightning network.

Q3What are the warning and watch zones?

Rings set round the airfield. A strike in the outer watch zone means a storm is near and staff should prepare. A strike in the inner warning zone means lightning is close and outdoor work should stop. The distances are set by the airport.

Q4Why does it matter for AGL work?

Lighting cables, circuits and fixtures are spread across the airfield, and crews work on them outdoors. A warning lets that work stop before lightning arrives, and the alert can be shown on the ALCMS.

Q5Does a lightning detector protect the lighting equipment?

No. It warns people. Equipment is protected by surge protection, earthing and bonding, which are covered in the Lightning Surge Interface and earthing entries.

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