The Dutch Association of Certified RPAS Operators (DCRO) conducted an industry study to challenge the assumptions in the Specific Operations Risk Assessment (SORA) 2.5 framework regarding the probability of a UAS flyaway. Based on real-world data, DCRO argues that the risk of a flyaway is significantly lower than currently estimated by regulators.

• Current Assumptions Are Overestimated:
  • SORA 2.5 assumes that a UAS will leave its operational volume once in 1,000 flight hours and experience a flyaway once in 10,000 flight hours.
  • DCRO’s data suggests the actual probability is 100 times lower, with a UAS leaving its operational area around 1 in 100,000 flight hours and a flyaway occurring in 1 in 1,000,000 flight hours.
• Data Sources & Methodology:
  • Data was collected from 37 DCRO member companies, four major foreign operators, and DJI (for enterprise models).
  • The dataset spans from 2011 to 2023, covering 1.4 million flight hours.
  • Only one confirmed flyaway was recorded in the dataset, equating to a probability of 1.41e-6.
  • DJI provided model-specific data, confirming an average probability of 1.75e-5 for a UAS leaving its operational volume.
• Professional Operators vs. Hobbyists:
  • The study focuses on professional drone operators who follow strict operational procedures and maintenance protocols.
  • The findings do not apply to recreational or non-certified operators, where the probability of incidents is likely higher.

Regulatory Concerns

• Overly Conservative Containment Measures:
  • The ground risk buffer under SORA 2.5 is considered excessive for professional operators.
  • Flight Termination Systems (FTS), often required for containment, may increase safety risks due to malfunctions, potentially leading to uncontrolled crashes.
• Lack of Industry-Wide Data Collection:
  • Currently, no European regulatory authority systematically collects UAS safety data.
  • DCRO calls for mandatory, standardized data collection across EU member states.

Recommendations

1. Improve Data Collection:
   • EASA and national CAAs should establish uniform reporting standards for UAS incidents.
   • Data should include not only flyaways but also crashes, technical failures, and human errors.
2. Adjust Containment Requirements:
   • Given the extremely low probability of a flyaway, the current SORA containment framework should be revised.
   • Flight Termination Systems should not be mandated for professional operators in the Specific Category.

Conclusion

The probability of a UAS flyaway is significantly lower than what regulators assume. The current SORA 2.5 containment rules create unnecessary burdens for professional operators without a corresponding safety benefit. DCRO urges regulatory changes to align risk assessments with real-world data.

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6 January 2025