A Part 135 operator is an entity holding a specific certification from the Federal Aviation Administration (FAA) that allows it to conduct commercial air transport for compensation or hire. This regulatory framework is established under Title 14 of the Code of Federal Regulations, specifically Part 135 (14 CFR Part 135), which governs non-scheduled commercial air operations. Obtaining this certification demonstrates a commitment to a higher level of safety and operational rigor than is required for private flying. The designation is an important marker of reliability, ensuring that aircraft, pilots, and operational procedures all meet commercial-grade standards for public transport.
Defining Part 135 Operations
Part 135 governs operations classified as “on-demand” or “commuter” air services, distinguishing them from the large, scheduled airline model. The defining feature of a Part 135 operation is the transport of passengers or cargo for which the operator receives payment. These services commonly include air taxi operations, private jet charters, and specialty services such as medical flights or air ambulance transport.
The regulation applies to aircraft with 30 or fewer passenger seats and a maximum payload capacity of 7,500 pounds, covering everything from light turboprops and small jets to commercial helicopter operations. Operators must secure an air carrier certificate, which subjects them to stringent regulations concerning operational practices, pilot qualifications, and aircraft maintenance. The on-demand nature of these services means they operate outside of fixed schedules, offering customers a flexible travel solution.
Distinguishing Part 135 from Other Flight Rules
Understanding Part 135 requires a comparison with the two other major regulatory frameworks that govern civil aviation in the United States: Part 91 and Part 121. The core difference lies in the commercial nature of the flight and the degree of regulatory oversight. Part 91, which covers General Operating and Flight Rules, is the baseline for all civil aircraft, primarily applying to private and non-commercial operations.
The key distinction is that Part 91 flights cannot transport passengers or cargo for compensation or hire, making the commercial transaction the dividing line with Part 135. Part 91 operations offer the most flexibility, with less stringent requirements for pilots and maintenance standards.
Conversely, Part 121 governs scheduled air carriers, which are the large-scale passenger and cargo airlines that operate under fixed, high-volume schedules. Part 121 requires the largest aircraft and imposes the most comprehensive and demanding safety protocols, reflecting the high passenger volumes involved. Part 135 operates in the space between these two, offering the on-demand flexibility that private aviation clients seek, while still adhering to commercial standards significantly stricter than Part 91.
Operational Control and Safety Requirements
Part 135 operators must adhere to safety controls that impose higher standards on flight execution and crew management than those for private flights. These regulations are designed to mitigate risks associated with commercial transportation, especially concerning pilot fatigue. Pilots flying under Part 135 are subject to strict duty time limitations, including a minimum rest period of at least 10 consecutive hours immediately preceding any flight assignment. For a two-pilot crew in unscheduled operations, the maximum flight time is generally limited to 10 hours during any 24-consecutive-hour period.
Operators must implement a formal Operational Control structure, which is a defined management system responsible for authorizing, initiating, and terminating all flights. This system requires key management personnel, such as a Director of Operations and a Chief Pilot, to oversee the daily activities of the air carrier. Part 135 also requires robust flight following procedures, which mandate that the operator tracks the flight’s progress and maintains communication with the crew throughout the operation.
Aircraft Maintenance and Inspection Standards
Aircraft operating under Part 135 are subject to a continuous airworthiness maintenance program, which is more rigorous and frequent than the requirements for private aircraft. This framework mandates that operators maintain their aircraft under stringent inspection schedules that go beyond the basic annual or 100-hour inspections typically required for Part 91 aircraft. Operators of aircraft with 10 or more passenger seats are required to maintain and report on service difficulty and mechanical interruptions.
Part 135 requires a comprehensive system of oversight, with mandated inspections performed by qualified mechanics. Detailed record-keeping is a non-negotiable requirement, ensuring that all maintenance, preventive maintenance, and alterations are meticulously documented without any gaps. The continuous analysis and surveillance of the maintenance program by the operator, alongside regular FAA inspections, ensures the aircraft remains in a condition acceptable for commercial passenger transport.
The Business of Part 135: Certification and Use
Achieving Part 135 certification is a rigorous, multi-phase process administered by the FAA to ensure a company is capable of operating safely for hire. The certification typically involves five distinct phases: pre-application, formal application, document compliance, demonstration, and final inspection/certification. The formal application phase requires the submission of a comprehensive package, including a General Operations Manual (GOM) and a Maintenance Manual, which detail the company’s policies and procedures.
The demonstration phase shifts the focus from documentation to practical evaluation, requiring the operator to perform proving tests with FAA inspectors aboard to verify operational capabilities. Consumers choose Part 135 operators because this certification provides a regulated assurance of safety that is not present in private aviation. This business model successfully combines the flexibility of on-demand travel with the regulated, commercial standards of safety and maintenance.