What is a frangible component?
The deliberate weak point in an elevated light. It holds the light upright in normal use, then breaks cleanly if an aircraft or vehicle strikes it, so the light yields instead of doing damage.
Elevated lights stand above the ground near runways and taxiways, where a wing or a vehicle can strike them. The frangible component is built in so that the light gives way and does little harm.
1It is a planned weak point
It is usually a breakaway coupling or a weakened section of the stem, placed just above the base. In normal use it is strong enough to carry the light head through wind and service. Under impact it breaks or separates cleanly at a known point.
2It protects more than the aircraft
The lower part stays fixed in the base, so the break leaves a short, low stump. The slack secondary lead lets the head separate without tearing the lead from the transformer or damaging the base and connector.
3Fit it right, and replace it right
Look for cracks, corrosion, a bent stem, a wrong or home-made replacement part and an over-tightened or loose coupling. After a strike, replace broken parts with the correct manufacturer part, refit to the specified torque, and check the lead, connector and base.
| Element | Detail |
|---|---|
| Frangible component | Coupling or weakened section designed to break on impact |
| Location | Just above the base, below the light head |
| Purpose | Let the light give way so it does not damage an aircraft |
| Stays behind | Base and transformer, with the cable intact |
| After impact | Replace broken parts and check the lead, connector and base |
| Check | Cracks, corrosion, correct part, specified torque, upright fit |
Frequently Asked Questions
Q1What is a frangible component in an airfield light?
A part of an elevated light, usually a coupling or a weakened section of the stem, designed to break or separate when struck so that the light gives way instead of damaging an aircraft.
Q2Why must the break point be in the right place?
It must break cleanly at a known point, above the base, so that the lower part stays fixed, the cable is not torn out and the break does not make a dangerous stump. Fitting it in the wrong place or with the wrong part changes how it fails.
Q3What should be checked and replaced after an impact?
Check the coupling, stem, lead and connector, and the base. Replace broken or cracked frangible parts with the correct manufacturer part, refit it to the specified torque, and confirm the light is upright and the lead is intact.
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