What are elevated approach fixtures?
The lights themselves: a lamp housing on a breakaway stem, aimed up the approach so a pilot can see it from far out.
An elevated approach fixture is an approach light mounted above the ground on a stem or mast, so it sits in the approach lighting plane. It has a lamp housing with optics, an aiming adjustment, a frangible coupling, a stem and a base plate that bolts to the foundation.
Centreline and crossbar fixtures show white. Some systems also use red lights, such as the red side-row barrettes of ICAO Category II/III systems and of ALSF-2. Each fixture is aimed toward the approaching aircraft. The aiming is set during installation and checked again after maintenance. The fixture is kept light so the stem stays frangible, and it is powered by a short lead from the transformer can below ground.
ICAO Annex 14 requires elevated approach lights and their supporting structures to be frangible. Beyond 300 m from the threshold, where a supporting structure is taller than 12 m, the requirement applies to the top 12 m only.
Frequently Asked Questions
Q1What is an elevated approach fixture?
It is an approach light mounted above the ground on a frangible stem or mast, so that it sits in the approach lighting plane and can be seen by a pilot on approach.
Q2What are the main parts of the fixture?
A lamp housing with its optics, an aiming adjustment, a frangible coupling, a stem and a base plate that bolts to the foundation.
Q3How is the light aimed?
It is aimed toward the approaching aircraft. The aiming is adjustable, set during installation to the design, and checked again after any maintenance or impact.
Q4How is it different from an inset fixture?
An inset fixture sits flush in the pavement. An elevated fixture stands above the ground on a stem, which is how most approach lights are mounted.
Q5Why must the fixture itself be light?
A heavy light on a frangible stem would carry more energy into an aircraft that hits it. Keeping the fixture and stem light helps the structure break away.
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