I often hear from my clients: “Oh, my friend is renting me their aircraft,” or “I’m getting an aircraft from another broker for much cheaper.” When checking the registration, it turns out to be an aircraft registered only for private use. Why is using a private aircraft such a big deal? After all, the owner uses it for their own private flights, and they seem as safe as can be. Let’s explore this issue.

The world of private aviation follows the rules and regulations published by the Federal Aviation Regulations, which is the governing body in the USA, or the European Authority for Aviation Safety, which is for countries within the EU. Most states adhere to the guidelines for the FAA or the EASA, both of which are very comprehensive. The choice between them is a topic for another day. For this article, to keep things simple, we’ll use the FAA as our guide. 

Three critical issues make a compelling reason why you should choose a properly certified charter operator: Maintenance, Crew Duty Times, and Insurance. We will go into brief detail for each, and if you really want to go deep into the topic, you’ll find the links to these regulations below. If you just want to do a big one-liner, here it is: Commercial operations have a higher standard of maintenance, stricter crew working durations, and higher insurance limits, which are more expensive.

What are Part 91 operations?

Part 91 operations refer to private aviation flights regulated by the Federal Aviation Administration (FAA). These flights are typically conducted by aircraft owners for personal use, without compensation or hire. The term “Part” comes from the FAA’s regulations, which are divided into different parts for organizational clarity. Part 91 has a long history, evolving from early aviation rules to the comprehensive regulations we have today. While Part 91 offers flexibility in flight planning and operations, it has less stringent maintenance requirements, crew duty limits, and insurance coverage compared to commercial flights under Part 135.

What are Part 135 operations?

Part 135 operations refer to commercial aviation flights regulated by the Federal Aviation Administration (FAA). These flights are conducted by certified charter operators who offer services for hire. This term has a robust history, evolving to ensure higher safety and operational standards. These regulations impose stricter maintenance requirements, crew duty limits, and higher insurance coverage compared to private flights under Part 91, ensuring passenger safety and reliability.

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Maintenance

As we’ve said, Part 91 and Part 135 of the Federal Aviation Regulations (FARs) outline distinct maintenance requirements reflecting the operational and safety standards for different types of aviation activities. Here’s a detailed comparison focusing on maintenance requirements for each Part.

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Part 91 maintenance requirements

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Part 91 governs general aviation operations and includes less stringent maintenance requirements compared to Part 135, reflecting the non-commercial nature of these flights. Key aspects include:

Flexibility in maintenance. Aircraft owners can perform certain types of preventive maintenance on their aircraft.

Annual inspections. Aircraft under Part 91 must undergo an annual inspection by an FAA-certified mechanic or repair station.

Maintenance records. Owners must keep records of maintenance, alterations, and repairs but are given more discretion in the management and execution of maintenance schedules.

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Part 135 maintenance requirements

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Part 135 covers commercial operations, including charter flights and air taxi services, with more rigorous maintenance standards to ensure passenger safety. These operations must adhere to:

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Approved maintenance programs. Requires a formal, FAA-approved maintenance program that specifies routine and non-routine maintenance procedures, including detailed schedules and records.

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Continuous Airworthiness Maintenance Program (CAMP). Many Part 135 operators must participate in a CAMP, ensuring ongoing surveillance and analysis of aircraft maintenance needs. These have checks A, B, C, and D and depend on the number of hours flown and the age of the aircraft — more on these in later articles. 

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Strict recordkeeping. Detailed logs must be kept for all maintenance and repairs, with specific requirements for recording the work performed, by whom, and when.

Training requirements. Part 135 requires that personnel involved in maintenance and inspection are properly trained and qualified, ensuring a higher standard of oversight and execution.

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FAA oversight. Maintenance programs under Part 135 undergo regular FAA review and approval, ensuring compliance with the highest safety standards.

In summary, Part 135 imposes more structured and stringent maintenance requirements on operators, reflecting the increased responsibility of carrying paying passengers. These requirements ensure that aircraft are maintained to the highest standards, with regular oversight, formalized training for maintenance personnel, and detailed recordkeeping to track the airworthiness of each aircraft.

Crew duty time

Part 91 — Private operations crew duty time

Part 91 does not specify detailed crew duty and rest requirements as strictly as Part 135. It generally allows operators more flexibility in scheduling without the detailed restrictions found in Part 135. The focus under Part 91 is on ensuring that pilots do not operate aircraft when fatigued, but it leaves the specifics of duty time limitations and rest requirements more to the discretion of operators and pilots. For instance:

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Flexibility in scheduling. Operators can design schedules based on the crew’s availability and operational needs as long as safety is not compromised.

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Responsibility for operators and pilots. It is up to the operator and the pilots to ensure that they are fit for duty, taking into account the need for adequate rest and not being under the influence of fatigue.

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Sector limitations. While duty hours for the three sectors are not explicitly defined, the emphasis is on overall pilot well-being and avoiding fatigue.

Part 135 - Commercial unscheduled operations crew duty time

Part 135 specifies more detailed requirements for crew duty times, rest periods, and limitations, providing clearer guidelines for operators and crew members to follow, ensuring safety in commercial operations. For operations with three sectors:

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Duty period limitations. Part 135 outlines specific duty period limitations, which can vary based on factors such as start time and the number of flight segments. For example, a typical duty period might be limited to 14 hours if it involves flying three sectors, but this can be extended under certain conditions with adequate rest.

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Rest requirements. Following a duty period, Part 135 requires a minimum rest period that is often longer than the preceding duty period. For three sectors, if the total duty day was close to the maximum allowed, the subsequent rest period must be sufficient to prevent fatigue, typically 10 hours minimum, but can be more based on the duty time’s length and timing.

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Cumulative duty limitations. Part 135 also sets limits on the amount of duty time accumulated by a crew member over 7 consecutive days, ensuring that even with multiple short sectors, the cumulative fatigue does not compromise safety.

In summary, while Part 91 provides broad guidance focused on preventing pilot fatigue, Part 135 offers a structured approach with specific limitations and requirements for duty and rest periods, especially in the context of commercial unscheduled operations involving multiple sectors. This structured approach under Part 135 ensures that commercial operators maintain a high safety standard, taking into account the more demanding nature of commercial flight operations and the need for predictable, stringent regulations to mitigate fatigue among flight crews.

Insurance

The specific insurance requirements for operations under FAA Parts 91 and 135 can vary significantly due to the nature of the operations covered by each part. Here’s a general overview of how insurance requirements typically differ between Part 91.   

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Part 91 - Private operations insurance requirements

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Liability coverage. Part 91 operators are generally required to carry liability insurance that covers bodily injury and property damage. The specific amounts can vary based on the operator’s assessment of risk and the value of the aircraft.

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Passenger liability. While not federally mandated, it’s common practice for Part 91 operators to carry passenger liability insurance on a per-seat basis.

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No specific minimums by the FAA. The FAA does not prescribe specific minimum insurance requirements for Part 91 operators, leaving the determination of adequate coverage to the discretion of the operator and possibly state regulations or lender/lessor requirements.

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Part 135 - Commuter and on-demand operations insurance requirements

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Higher liability coverage. Due to the commercial nature of Part 135 operations, these operators are typically required to carry higher liability insurance coverage. This includes larger amounts for bodily injury, property damage, and passenger liability.

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FAA minimum requirements. The FAA sets minimum insurance requirements for Part 135 operators, which are significantly higher than for Part 91 operations. These minimums are based on the type of operation, the aircraft’s seating capacity, and other factors.

Key differences

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Mandated Insurance minimums

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Part 135 operations have specific minimum insurance requirements set by the FAA, while Part 91 operators are subject to less stringent federal requirements.

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Scope of coverage

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Part 135 insurance coverage requirements are generally broader and higher, reflecting the increased risk associated with carrying paying passengers or cargo.

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Regulatory oversight

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Part 135 operators are subject to more rigorous FAA oversight regarding insurance, including the need to prove adequate coverage as part of their certification process.

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It’s important for operators under both parts to also consider additional coverages such as hull insurance, which covers physical damage to the aircraft, and to regularly review their coverage to ensure it meets their operational needs and risk exposure. Operators should consult with insurance professionals and legal advisors to ensure compliance and adequate protection.

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Operating requirements

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Part 91 operations have more flexibility and fewer requirements regarding operational procedures, allowing for a broader range of activities without the need for detailed compliance documentation.

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Part 135 operations are subject to stricter operational control requirements, including detailed specifications for flight operations, crew management, and passenger handling to ensure safety and compliance with commercial standards.

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Training requirements

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Part 91 requires less formalized training for pilots and crew, focusing on general competencies and ensuring safety in private operations.

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Part 135 mandates comprehensive training programs for pilots, crew, and maintenance personnel, including initial and recurrent training to ensure proficiency in commercial operations.

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Aircraft equipment and specifications

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Part 91 allows for a broader range of aircraft with minimal equipment requirements, provided the aircraft meets general airworthiness standards.

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Part 135 requires aircraft to be equipped with specific safety equipment and to meet higher airworthiness standards, reflecting the increased risk associated with carrying paying passengers.

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Flight operations

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Part 91 offers greater latitude in flight operations, including fewer restrictions on flight paths, altitudes, and operational procedures, catering to the flexibility needed for private flights..

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Part 135 imposes more rigorous flight operation standards, including stricter rules on flight paths, altitude minimums, and weather requirements to enhance passenger safety.

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Recordkeeping and reporting

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Part 91 has less stringent requirements for recordkeeping and reporting, focusing on basic documentation of aircraft maintenance and flight operations.

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Part 135 requires detailed recordkeeping and reporting, including maintenance records, flight data, and passenger information, to facilitate oversight and ensure compliance with commercial operation standards.

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Drug and alcohol testing

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Part 91 does not generally require drug and alcohol testing for crew members.

Part 135 mandates comprehensive drug and alcohol testing programs for all safety-sensitive personnel to promote safety and compliance with federal regulations.

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These points illustrate the overarching emphasis on safety, compliance, and operational rigor in Part 135 commercial operations compared to the more flexible framework governing Part 91 private operations. Each set of regulations is tailored to the specific risks and needs of its operational domain, ensuring that safety remains paramount while accommodating the varying scopes of aviation activities. 

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It’s worth noting that the stricter the regulations, the higher the cost to maintain the specific aircraft. Commercial operators use multiple crews to enhance efficiency, which is more expensive compared to private companies with just one crew for the owner’s needs. In terms of safety, an individual may want to make back-to-back flights, causing crew fatigue.

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Though the final decision rests with the team, they may feel pressured to fly despite tiredness to avoid losing their jobs and keep the owner happy. As a result, while private registration can be more costly, chartering from a commercial operator is definitely safer.

Conclusion 

In summary, if you want to charter a private jet, it’s essential to understand the differences between Part 91 and Part 135 operations. The first one covers private flights with less stringent rules. Part 135, in turn, governs commercial flights with higher standards for maintenance, crew duty, and insurance. 

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Certified operators adhere to stringent maintenance protocols, ensuring your safety and peace of mind. So, next time you consider a private jet charter, make sure it’s with a reputable operator who meets the necessary regulatory standards.  

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https://www.ecfr.gov/current/title-14/chapter-I/subchapter-F/part-91?toc=1

https://www.ecfr.gov/current/title-14/chapter-I/subchapter-G/part-135

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