How is the TLOF perimeter lit?
A border of green omnidirectional lights on the edge of the touchdown surface, inside the FATO.
The touchdown and lift-off area (TLOF) is the load-bearing surface inside the FATO where the helicopter touches down and lifts off. At night its edge is shown by fixed green omnidirectional lights, so the pilot sees exactly where the surface is that will carry the aircraft.
On a square or rectangular TLOF there are at least four lights along each side, including one at each corner. On a circular TLOF there are at least 14 lights, evenly spaced on the circle. Spacing is not more than 5 m at a surface-level heliport and not more than 3 m at an elevated heliport or helideck. The lights stay low, frangible or inset so they are not a hazard to the helicopter.
Mark the touchdown surface where the helicopter lands.
Mark the larger approach and take-off area around it. See Entry 1.
Frequently Asked Questions
Q1What is TLOF perimeter lighting?
Fixed green lights along the edge of the touchdown and lift-off area (TLOF), the load-bearing surface where the helicopter actually touches down. They show the pilot the exact area that will carry the helicopter.
Q2How is it different from FATO perimeter lighting?
The FATO lights mark the edge of the larger approach and take-off area; the TLOF lights mark the smaller touchdown surface inside it. Seeing two rings tells the pilot both the clear area and the place to land. FATO lights are covered in Entry 1.
Q3What colour and type are TLOF perimeter lights?
Under ICAO Annex 14 Volume II they are fixed, omnidirectional lights showing green. National regulators may add requirements such as intensity or night-vision-goggle compatibility, so check the standard in force.
Q4How many lights does a TLOF need?
On a square or rectangular TLOF, ICAO Annex 14 Volume II calls for at least four lights along each side, including one at each corner, evenly spaced. On a circular TLOF it calls for at least 14 lights, evenly spaced on a circle. Spacing limits are not more than 5 m at a surface-level heliport and not more than 3 m at an elevated heliport or helideck.
Q5Where are the lights placed?
On the edge of the TLOF, or within 1.5 m of it, so the lit boundary matches the area that can carry the helicopter. Lights stay low, frangible or inset so they do not become a hazard under downwash or to a helicopter on the surface.
Q6Which standards apply?
ICAO Annex 14 Volume II covers heliports, and national regulators publish their own requirements, such as the FAA heliport design advisory circular. Light count, spacing and height differ between them, so confirm against the standard in force and the project specification.
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