The distinction between Part 91 and Part 135 is not merely regulatory taxonomy. It determines the specific crew qualifications required for every flight, the training and checking obligations that fall on the operator, the rest and duty time rules that govern crew scheduling, and the liability exposure that comes with using contract crew who do not meet the applicable standard. Operators who move between Part 91 and Part 135 operations need to understand exactly where the requirements diverge and what that means for crew sourcing and documentation.
This guide addresses the most practically important differences in crew requirements between these two regulatory frameworks, with specific attention to how those differences affect the use of contract crew.
Part 135 governs commercial air taxi and on-demand charter operations where compensation is received for the carriage of persons or property. The FAA holds Part 135 certificate holders to a higher standard because they are operating in a commercial context where the public trust is directly implicated. This higher standard manifests throughout the crew requirements.
Under Part 91, pilots operating as pilot in command need a current medical certificate appropriate to the operation. For instrument flight rules operations in turbine aircraft, a second-class medical issued within the preceding 12 months is the standard for most pilots. The BasicMed pathway, which allows pilots to fly without a traditional FAA medical under specific circumstances, applies to some Part 91 operations.
Under Part 135, the requirements are stricter. A pilot in command in Part 135 operations must hold at least a second-class medical certificate issued within the preceding 12 months. For instrument operations, a first-class medical issued within the preceding 12 months is required. BasicMed is not sufficient for Part 135 operations under any circumstances.
When sourcing contract pilots, this distinction matters. A pilot whose first-class medical was issued 13 months ago technically holds a valid medical under Part 91 standards but fails the Part 135 requirement. This is a detail that operators moving between regulatory frameworks need to confirm explicitly rather than assuming.
This means that an operator cannot find a type-rated pilot through a platform and put them on a Part 135 revenue trip the same day. That pilot must first be enrolled in the operator's training program, complete the required initial training, and successfully complete a check ride under the operator's check airman. The time and cost of running a new contract pilot through this process is significant, which is exactly why Part 135 operators need to build their approved contract crew pool in advance during normal operations rather than in response to emergencies.
Operators building their Part 135 contract crew bench can identify and pre-vet candidates through CrewBlast and then run selected pilots through their training program to build an approved roster before emergencies arise. The identity verification and background check that CrewBlast has already completed reduces the due diligence burden on the operator's chief pilot for the initial candidate evaluation.
Under both Part 91 and Part 135, pilots must meet the recent flight experience requirements of FAR 61.57 three takeoffs and landings in the preceding 90 calendar days in the same category, class, and type of aircraft. Night currency is separate and requires the three takeoffs and landings to have been conducted at night.
Part 135 adds specific proficiency check requirements that go beyond the Part 91 flight review. Part 135 pilots must complete a proficiency check in the aircraft or in an approved flight simulator every 12 calendar months, with instrument competency checks required more frequently for instrument operations. These checks must be conducted by a designated check airman under the operator's training program not simply any CFI or check airman.
For contract pilots used in Part 135 operations, operators must maintain records of all required checks and have those records available for FAA inspection. Using a contract pilot whose check records are not in the operator's files exposes the certificate to enforcement action regardless of whether the pilot is personally current.
Part 135 imposes specific duty period limitations, minimum rest periods, and flight time limits that must be tracked and complied with for every pilot in every operation. A contract pilot who has already flown a significant duty day under Part 91 before arriving to fly a Part 135 trip must have their prior duty time accounted for in the rest calculations, even if the prior flying was under a different operator.
This is an area where operators using contract crew are particularly vulnerable. The contract pilot knows their own duty history. The operator, if they do not ask specifically, does not. A direct pre-trip conversation that addresses the pilot's duty and rest history in the preceding 24 hours is essential for Part 135 compliance when using contract crew.
Under Part 135, flight attendant requirements depend on the number of passengers and the configuration of the aircraft. For operations above certain passenger capacities, a certificated flight attendant is required by regulation. The flight attendant must complete initial training in the specific aircraft and hold a certificate of demonstrated proficiency.
Contract flight attendants used in Part 135 operations must meet the same training and checking requirements that apply to contract pilots they must be enrolled in the operator's training program and have completed the required aircraft-specific training before flying revenue operations. The contract flight attendant page covers the qualification requirements in detail for operators sourcing cabin crew.
Part 135 operators are required to maintain specific records for every crew member who flies under their certificate. For contract crew, this includes the training completion records, check ride documentation, medical certificate verification, and authorization records that demonstrate the pilot has been approved under the operator's program.
The practical implication is that a contract pilot cannot fly a Part 135 revenue trip without the operator having their records on file. This is not a process that can be completed in an hour before departure. Operators who want to use contract crew reliably for Part 135 operations must invest in building their approved contractor documentation well in advance.
For a practical overview of how to build a compliant contract crew system for both Part 91 and Part 135 operations, the operators page covers the full range of operator types and their specific crew management needs. The how it works page explains how the platform supports both regulatory contexts.