Part 135 of the Federal Aviation Regulations (FARs) is a critical framework governing specific types of commercial air operations in the United States. While traditionally associated with manned aircraft, understanding Part 135 is becoming increasingly relevant for the drone industry as it pushes the boundaries of autonomous flight and commercial service delivery. Essentially, Part 135 dictates the operational requirements for commuter and on-demand operations, often referred to as air charter services. This regulatory segment is designed to ensure the highest standards of safety, maintenance, and pilot proficiency for non-scheduled commercial flights, distinguishing it from scheduled airline operations (Part 121) and private operations.
The Foundation of Commercial Air Charter and Its Core Principles
At its heart, Part 135 outlines the rules for operators who offer passenger or cargo transportation for hire on an “on-demand” or “commuter” basis. Unlike major airlines flying fixed routes on a schedule, Part 135 operators provide flexibility, catering to specific customer requests for destinations and timings. This category includes a vast array of services, from executive air charters and air ambulance flights to scenic tours and specialized cargo deliveries. The stringent requirements under Part 135 are rooted in a foundational commitment to public safety, reflecting the inherent risks associated with carrying paying passengers or valuable cargo.
Key operational requirements for a Part 135 certificate holder include:
- Operational Control: The certificate holder must maintain direct control over all aspects of their operations, including flight scheduling, crew assignments, and aircraft dispatch. This central oversight ensures consistent adherence to safety protocols.
- Maintenance Programs: Aircraft must undergo rigorous and scheduled maintenance checks, often exceeding general aviation standards. Operators must have an FAA-approved maintenance program, employing qualified mechanics and maintaining meticulous records to ensure aircraft airworthiness.
- Pilot Qualifications and Training: Pilots operating under Part 135 must meet elevated experience, training, and testing standards compared to private pilots. This includes specific flight hours, instrument ratings, and recurrent training covering emergency procedures, adverse weather operations, and specific aircraft types. Proficiency checks are mandatory and frequent.
- Safety Management Systems (SMS): While not explicitly mandated for all Part 135 operators historically, there’s a growing emphasis on voluntary adoption of SMS, a proactive approach to identifying and mitigating risks before incidents occur. For larger or more complex operations, SMS is becoming standard practice.
- Aircraft Requirements: Aircraft used in Part 135 operations must be type-certificated for commercial use and equipped with specific safety features, navigation systems, and emergency equipment appropriate for the intended operations and flight environment.
These principles combine to create a comprehensive regulatory environment that fosters reliability and trust in on-demand air services. For the drone industry, these pillars of safety and operational rigor offer a blueprint for how complex, high-stakes uncrewed operations could be managed in the future.
Part 135 vs. Part 107: A Regulatory Divide for Uncrewed Systems
The existing regulatory landscape for drones in the United States is primarily defined by Part 107, which governs small Unmanned Aircraft Systems (sUAS) operations. Part 107 revolutionized commercial drone use, making it accessible with relatively straightforward rules for pilots and operational parameters (e.g., visual line of sight, maximum altitude, daylight operations). However, as drone technology advances, the limitations of Part 107 become evident, particularly for ambitious commercial applications.
Part 107 is ideal for many common drone tasks like aerial photography, inspections, and mapping, but it lacks the framework for operations that are increasingly envisioned, such as:
- Beyond Visual Line of Sight (BVLOS) flights over extended distances.
- Operations over people or at night without specific waivers.
- Transport of property for compensation or hire that crosses state lines or operates in complex airspace without specialized waivers.
- Future urban air mobility (UAM) concepts involving passenger or significant cargo transport.
This is where the principles of Part 135 become critical for the drone industry. Part 135 represents a significantly higher bar for operational complexity and safety assurance than Part 107. While Part 107 focuses on the small, relatively low-risk operations of individual drones, Part 135 is built for complex, potentially multi-aircraft operations, often involving the transport of people or valuable goods, where the consequences of failure are much higher. The regulatory gap between the simplicity of Part 107 and the complexity required for advanced drone services is substantial, and Part 135 offers a proven, albeit adaptable, pathway forward.
The Drone Industry’s Aspirations: Why Part 135 Matters
The drone industry is not content with basic operations. Companies are investing heavily in technologies for autonomous package delivery, aerial taxis, long-range infrastructure inspection, and even passenger transport via Electric Vertical Take-Off and Landing (eVTOL) aircraft. For these ambitious applications to become a reality, the FAA requires a regulatory framework that ensures an equivalent level of safety to traditional manned aviation. Part 135, with its established record for managing complex, non-scheduled commercial air operations, is increasingly viewed as the foundational template, or at least a significant reference point, for these advanced drone services.
Several drone companies and eVTOL developers are actively pursuing or exploring pathways to achieve some form of Part 135 certification. This isn’t about fitting a drone into an existing Cessna 206 regulation; rather, it’s about demonstrating that an uncrewed system can meet the intent of Part 135’s safety and operational rigor. This often involves:
- Type Certification for UAS: Before Part 135 operations, the drone itself needs a “type certificate” – an FAA approval that its design meets airworthiness standards for its intended use. This is a complex process, involving extensive testing and documentation, far beyond what’s required for a typical Part 107 drone.
- Operational Certification: The operator then needs an “operational certificate” (like a Part 135 certificate) that demonstrates they have the systems, personnel, training, and maintenance programs in place to operate the type-certified drone safely for commercial purposes.
- Addressing Unique UAS Challenges: Integrating drones into a framework designed for manned aircraft requires innovative solutions for remote piloting, command and control links, detect-and-avoid capabilities, and unique maintenance considerations for electric propulsion and complex automation systems.
By aiming for a Part 135-like level of regulatory compliance, drone operators signal to the FAA and the public that their operations are not merely experimental but are built upon a robust foundation of safety and reliability, comparable to established aviation practices.
Challenges and Future Adaptations for Drone Integration
While Part 135 offers a robust framework, directly applying all its rules to uncrewed systems presents significant challenges. Many of Part 135’s stipulations are inherently designed for human pilots onboard an aircraft, such as requirements for medical certificates, pilot rest rules, and emergency procedures executed by a crew. Adapting these for remotely piloted or fully autonomous systems requires a nuanced approach.
The FAA is actively working on modernizing its regulations and creating pathways for advanced drone operations. This often involves:
- Performance-Based Regulations: Moving away from prescriptive rules (e.g., “must have a pilot in the cockpit”) towards performance-based standards (e.g., “must demonstrate equivalent level of safety in control and decision-making”). This allows for technological innovation while maintaining safety goals.
- Special Airworthiness Certificates: Initial approvals for novel UAS designs often come through special airworthiness certificates, allowing for testing and data collection under specific conditions, gradually leading to full type certification.
- Integrated Pilot and Operator Certification: For complex UAS, the FAA might develop new certifications that combine aspects of traditional pilot certificates with a deeper understanding of ground control systems, data links, and autonomous flight management.
- Future Concepts like Urban Air Mobility (UAM): For concepts like eVTOL passenger transport, the FAA is exploring how Part 135 can be adapted, or new rules created, to incorporate these advanced aircraft, ensuring they meet the stringent safety levels expected for carrying people.
The ultimate goal is not to force drones into a regulation that doesn’t fit, but to leverage the proven safety principles of Part 135 to build new, appropriate regulatory frameworks for advanced drone operations. This involves close collaboration between industry and regulators to define equivalent levels of safety, operational procedures, and pilot/operator qualifications suitable for the unique characteristics of uncrewed aviation.
Ensuring Safety and Reliability in Advanced Drone Operations
At its core, the relevance of Part 135 for drones boils down to safety and public trust. As drones take on more complex, critical, and potentially higher-risk roles—like delivering urgent medical supplies, inspecting critical infrastructure over vast distances, or even carrying passengers in future air taxi services—the need for a robust regulatory oversight becomes paramount. The rigorous standards embedded in Part 135 for operational control, maintenance, and personnel qualification are not arbitrary; they are the result of decades of learning from aviation incidents and developing best practices to prevent them.
For the drone industry to truly scale and gain widespread public acceptance for advanced operations, it must demonstrate a commitment to safety that rivals traditional aviation. This means embracing detailed operational manuals, implementing comprehensive safety management systems, ensuring robust training for remote pilots and ground crews, and designing aircraft with redundant systems and fail-safes. The principles of Part 135 provide a proven blueprint for achieving this. By understanding and adapting these established aviation safety protocols, drone operators can build the necessary trust and regulatory approval to unlock the full potential of advanced uncrewed air services, transforming the future of air commerce and mobility.