Where an object, regardless of its height, has been assessed as constituting an obstacle to air navigation, it requires marking and/or lighting.
The following objects must be marked and/or lighted in accordance with the Canadian Aviation Regulations
- Any object penetrating an airport obstacle limitation surface (OLS)
- Any object greater than 90 metres above ground level (AGL) within 6 km of the geographical centre of an aerodrome
- Any permanent catenary wire crossing where any portion of the wires or supporting structures exceeds 90 metres AGL
- Any object greater than 150 metres AGL