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:
- notify the Regional office of Transport Canada by filing the aeronautical assessment form for obstruction marking and lighting (PDF, 784 KB)
- notify NAV CANADA's Land Use Program, primarily for communication and radar interference concerns
- mark and light the object in accordance with the requirements of Standard 621
A notification is required to Transport Canada Marine Administration when the object is to be located offshore or on navigable waterways.