3.1 Altitude Limits, Bystander Separation & Right of Way
Key Takeaways
- CAR 901.25 establishes a standard maximum operating altitude of 400 feet (122 metres) Above Ground Level (AGL) for all RPAS operations in Canada.
- Under CAR 901.25(1)(b), an RPA within 200 feet (61 m) horizontally of a tall structure may fly up to 100 feet (30 m) above that structure's highest point.
- Under CAR 901.26 and 901.53, Basic operations mandate maintaining a minimum horizontal separation of 30 metres (100 feet) from all bystanders at all times, with zero overflight permitted.
- Under CAR 901.17, remotely piloted aircraft must yield right-of-way to all crewed aircraft—including airplanes, gliders, airships, and balloons—immediately vacating their flight path.
Altitude Limits, Bystander Separation & Right of Way
In Canadian aviation law, the operation of remotely piloted aircraft systems (RPAS) is governed by Part IX of the Canadian Aviation Regulations (CARs). For pilots holding a Pilot Certificate — Small Remotely Piloted Aircraft (VLOS) — Basic Operations, the operational envelope is strictly bound by numerical limits designed to prevent collisions with crewed aircraft and protect people and property on the surface.
Every Basic RPAS pilot must master three fundamental legal pillars: altitude ceilings, bystander horizontal separation, and crewed aircraft right-of-way.
Regulatory Altitude Limits: The 400-Foot Ceiling (CAR 901.25)
Under CAR 901.25(1)(a), no pilot shall operate a remotely piloted aircraft at an altitude greater than 400 feet (122 metres) Above Ground Level (AGL). Exactly 400 ft AGL is legal; 401 ft is not. CAR 901.25(2) is the only relief: a higher (or lower) ceiling may be set by a special flight operations certificate — RPAS issued under CAR 903.01.
Why 400 Feet AGL?
Canadian airspace is designed to separate crewed and uncrewed aviation through an altitude buffer. Under CAR 602.14, crewed aircraft operating under Visual Flight Rules (VFR) are generally prohibited from flying lower than:
- 500 feet AGL over non-congested areas, open water, or rural terrain (except during takeoff and landing);
- 1,000 feet above the highest obstacle within a horizontal radius of 2,000 feet over built-up areas or open-air assemblies.
The 400-foot ceiling for RPAS creates a mandatory 100-foot safety buffer (between 400 feet and 500 feet AGL) that separates low-flying crewed traffic from uncrewed operations.
True AGL vs. Launch Point Datum
A common failure point on the Transport Canada Small Basic exam involves calculating Above Ground Level (AGL) over varying terrain:
- Most consumer and commercial RPAS determine altitude using internal barometric altimeters or GNSS sensors referenced to the takeoff point (home point) as 0 feet AGL.
- The legal definition of AGL under CAR 901.25 refers to the actual distance between the aircraft and the surface of the earth directly beneath it at any given point during flight.
- Terrain Traps: If you launch an RPA from the edge of a 300-foot cliff and fly out over the adjacent valley floor while maintaining an indicated altitude of 200 feet relative to your takeoff point, the aircraft is actually flying at 500 feet AGL relative to the ground below. This constitutes a direct violation of CAR 901.25(1).
The Structural Inspection Altitude Exception (CAR 901.25(1)(b))
Recognizing the necessity of using drones for inspecting tall industrial infrastructure, Transport Canada provides an explicit legal exception in CAR 901.25(1)(b).
An RPA may exceed the standard 400-foot AGL ceiling if both of the following conditions are strictly met:
- Horizontal Distance Limit: The RPA is operated within a horizontal distance of no more than 200 feet (61 metres) from a building or structure; and
- Vertical Ceiling Limit: The RPA does not fly higher than 100 feet (30 metres) above the highest point of that building or structure.
Calculation Example
| Structure Parameter | Value |
|---|---|
| Structure Height | 650 feet AGL |
| Maximum Permissible Horizontal Distance | 200 feet (61 m) |
| Maximum Permissible Operating Altitude | 750 feet AGL (650 ft + 100 ft) |
Exam Tip: If the RPA moves 201 feet horizontally away from the perimeter of that 650-foot building, the structural exception immediately ceases to apply, and the standard 400-foot AGL ceiling takes effect. The pilot would immediately be in violation by 350 feet!
Crewed aircraft are required to avoid tall obstacles by substantial margins, creating a safe operational cylinder around the structure where an RPA can operate at elevated heights without conflicting with VFR traffic.
Bystander Definition & Separation Buffers (CAR 901.26 & 901.53)
Under a Basic Pilot Certificate, flights are restricted to uncontrolled airspace (Class G) and must adhere to strict stand-off distances from non-participating people.
Definition of a Bystander
Under Transport Canada guidelines and CARs Part IX, a bystander is defined as any person not directly participating in the operation of the remotely piloted aircraft system.
- Flight Crew (Participating): The Pilot-in-Command (PIC), certified Visual Observers (VOs), and essential flight operations personnel assigned specific safety roles.
- Bystanders (Non-Participating): Spectators, passersby, clients, construction workers, property owners, and members of the general public.
Critical Legal Distinction: Verbal permission or signed waivers do not convert a bystander into a participating flight crew member. Even if a client stands beside you watching the monitor and verbally consents to the flight, they remain legally classified as a bystander under CARs Part IX.
The 30-Metre Horizontal Separation Rule
Under CAR 901.26 and CAR 901.53, a pilot conducting Basic operations must maintain a minimum horizontal distance of 30 metres (100 feet) between the RPA and any bystander at all times during flight.
Key aspects of the 30-metre rule:
- Horizontal Measurement: The distance is measured horizontally along the ground plane, forming an imaginary protective cylinder around every non-participating individual, extending infinitely upward.
- No Direct Overflight: Basic operations strictly prohibit flying directly over any person, regardless of how high the aircraft is flying.
- Dynamic Response to Inadvertent Intrusion: If a pedestrian enters the 30-metre perimeter while the RPA is airborne, the PIC must immediately pause mission progress, maneuver the RPA away to re-establish the 30-metre buffer, or safely land the aircraft.
| Operating Category | Distance from Bystanders | Direct Overflight Allowed? |
|---|---|---|
| Basic Operations | Minimum 30 metres (100 feet) horizontal | Prohibited at all altitudes |
| Advanced Operations | 30 m to 5 m (with declared RPA) | Permitted only with manufacturer safety declaration |
Crewed Aircraft Right-of-Way Rules (CAR 901.17)
In Canadian aviation, the right-of-way hierarchy is unambiguous: RPAS occupy the absolute bottom of the hierarchy.
Under CAR 901.17, a pilot of a remotely piloted aircraft system must give way to all power-driven heavier-than-air aircraft, power-driven lighter-than-air aircraft, gliders, and balloons at all times.
Operational Requirements for RPAS Pilots
- Active Collision Avoidance: The RPAS pilot must continuously scan the airspace visually and listen for acoustic cues (propeller buzz, jet turbine whine, helicopter rotor slap).
- Immediate Maneuver: Upon sighting or hearing an approaching crewed aircraft, the RPAS pilot must immediately maneuver the RPA clear of the crewed aircraft's path. This typically requires descending to a low altitude or landing immediately.
- No Expectation of Being Seen: High-speed airplanes and low-flying helicopters travel at speeds between 90 and 250+ knots. A small drone is practically invisible to a crewed aircraft pilot. The entire legal burden of detection and avoidance rests on the drone pilot.
- Wake Turbulence Avoidance: The PIC must also account for violent downwash and wingtip vortices generated by helicopters and heavy aircraft, which can easily destabilize or destroy an RPA several hundred metres away.
What is the standard maximum operating altitude for an RPA under Basic Operations according to CAR 901.25?
Under CAR 901.25(1)(b), an operator is inspecting a 600-foot communications tower. What is the maximum altitude and horizontal distance permitted for this operation?
Under Canadian Aviation Regulations for Basic RPAS operations, what is the minimum required horizontal distance that must be maintained between the RPA and any bystander?
While operating an RPA at 250 feet AGL in Class G airspace, the pilot observes an incoming floatplane flying low along a river corridor. Under CAR 901.17, what action is legally required?