Air navigation obstacle marking and lighting


When is an object an obstacle

According to the Canadian Aviation Regulations (CARs) 601.23 an object is an obstacle if:

  • higher than 90 meters above ground level (AGL) and located within 6 kilometers of the geographical centre of an aerodrome
  • higher than 90 meters AGL and is located within 3.7 kilometers of the centreline of a recognized VFR route
  • higher than 150 meters AGL
  • in the case of any catenary wires crossing over a river, any portion of the wires or supporting structures is higher than 90 m AGL

An object may also be an obstacle if it penetrates an airport Obstacle Limitation Surface (OLS) or Obstacle Identification Surface (OIS) as detailed in Aerodrome Standards and Recommended Practices (TP 312).

Further, an object may also be deemed an obstacle, if so determined by Transport Canada. Refer to CAR 601.25.

Putting up an object

If you are putting up an object that will be an obstacle, you must:

A notification is required to Transport Canada Marine Administration when the object is to be located offshore or on navigable waterways.

Related links