RPAS Advanced Sheltered Ops - Is it Safe?

 By: Colonel (ret) Bernie Derbach, KR Droneworks, 05 Jan 26

Canada's introduction of Sheltered Operations (effective November 4, 2025) represents a paradigm shift in drone regulation.

By acknowledging that physical structures act as a "shield" against mid-air collisions with crewed aircraft, the regulator has created a legal framework for Beyond Visual Line of Sight (BVLOS) flights without the typical requirements of visual observers or expensive Detect and Avoid (DAA) technology.

1. Regulatory Overview & Distances: Under the amended Canadian Aviation Regulations (CARs), sheltered operations are restricted to Advanced Pilot Certificate holders using Small RPAS (250 g to 25 kg).

Specified Spatial Limits:

• Vertical: Maximum 100 feet (30 m) above the height of the building or structure.

• Horizontal: Maximum 200 feet (61 m) from the building or structure.

• Safety Buffer: Must remain 100 feet (30 m) away from uninvolved persons at all times.

• Range Limit: The drone must remain within 2 nautical miles (3.7 km) of the pilot and control station.

2. Operational & Safety Analysis

The "Shielding" Philosophy: The primary safety justification is that crewed aircraft (planes/helicopters) do not fly within 100 feet of a building. Therefore, the structure provides a "shelter" where the risk of a mid-air collision is statistically negligible. This removes the regulatory necessity for a Visual Observer (VO) to scan the skies, as the airspace is "atypical."

Operational Advantages:

• Efficiency: Inspections of high-rise buildings, bridges, and industrial stacks no longer require a team of observers stationed at different angles to maintain VLOS.

• Cost: Significant reduction in personnel costs and logistical planning.

• Precision: Pilots can focus on the camera feed (FPV) for detailed structural analysis without the distraction of maintaining direct line-of-sight.

Safety Concerns & Technical Risks:

• C2 Link Degradation: Operating on the "other side" of a building introduces Non-Line-of-Sight (NLOS) signal challenges. Physical structures (especially steel and concrete) cause signal attenuation and multi-path interference, which can lead to a lost command-and-control (C2) link.

• GPS Multipath/Occlusion: Large structures can block GPS satellite signals or cause "multipath" errors where signals reflect off walls, leading to significant horizontal drift or "fly-aways" in automated modes.

• Communication Latency: If using cellular-based links (LTE/5G) to circumvent physical blockages, latency must be managed to ensure the 200-foot horizontal boundary is not breached during a lag spike.

3. Global Context: JARUS & International Standards: Transport Canada’s rules align closely with the JARUS (Joint Authorities for Rulemaking on Unmanned Systems) SORA (Specific Operations Risk Assessment) framework.

JARUS SORA 2.5 Standards:

JARUS defines "shielded" airspace as an area where the probability of encountering a crewed aircraft is extremely low because of the proximity to obstacles.

• Standard Scenarios: JARUS recommends that for sheltered operations, the Air Risk Class (ARC) can be reduced to the lowest level (ARC-a), effectively waiving the need for DAA.

• Containment: JARUS emphasizes "Containment" (Step 9 of SORA). If a drone loses its link behind a building, the system must have a robust "Return to Home" (RTH) that accounts for the structure (e.g., climbing before returning) to avoid crashing into the very building it is "sheltering" behind.

Comparison with Other Jurisdictions:

• EASA (Europe): Uses Pre-Defined Risk Assessments (PDRA-G03). Like Canada, EASA allows "shielded" flight within 30m of an obstacle, recognizing it as "atypical airspace."

• FAA (USA): Historically requires a waiver (Part 107.31) for BVLOS. However, the FAA's ASSURE research group has been pushing for "shielded" standards similar to Canada's to streamline infrastructure inspections.

4. Summary Table: Safety vs. Operational Flexibility

Feature	Operational Perspective	Safety Perspective
No Visual Observer	Reduces crew size; simplifies logistics.	Increases reliance on pilot telemetry and system reliability.
Behind Structures	Enables full 360° inspections from one spot.	High risk of C2 link loss and GPS signal degradation.
30m/61m Limits	Clearly defines the "safe zone" for work.	Difficult to judge precisely without specialized sensors (Lidar/Ondar).
2nm Range	Allows for large-scale industrial site work.	Risk increases if the pilot is far from the "landing/recovery" site.

References

1. Transport Canada: 2025 Summary of changes to Canada's drone regulations. (Nov 2025).

2. JARUS: SORA Annex F: Theoretical Basis for Ground Risk Classification and Mitigation. (Version 2.5).

3. EASA: Easy Access Rules for Unmanned Aircraft Systems (PDRA-G03). (July 2024).

4. FAA ASSURE: A45-Shielded UAS Operations: Detect and Avoid (DAA) Final Report. (2024)