In aviation, the rules you fly under matter. If you miss a required inspection or fly under the wrong type of operation, your aircraft could be grounded. You could even face fines or lose your insurance. Many pilots don't know how much freedom and responsibility come with flying under Part 91.
Part 91 aviation gives you more flexibility than airline or charter rules. But that freedom also means you need to understand the limits. One small mistake, like flying passengers for money without the right certification, can lead to serious trouble.
So what does Part 91 actually cover? How is it different from Parts 121 and 135, which apply to airlines and charter companies? This article will explain those differences so you can stay safe and legal.
You'll also learn how SOMA Software helps you track inspections, manage maintenance, and stay compliant—no matter how you fly.
Part 91 is a set of FAA rules that covers how private and non-commercial flights must be operated in the United States. It's part of Title 14 of the Code of Federal Regulations (CFR), which includes all the rules for flying, maintenance, and aircraft safety. These rules apply to things like personal flights, business flights that don't involve paying passengers, flight training, and even flying for fun.
Part 91 sets the basic safety and maintenance rules for most aircraft in the U.S.—from small trainers to large corporate jets. It's the most flexible of the FAA's rules because it's made for operators who aren't flying for hire. It also allows some things that commercial operators can't do, like carrying small amounts of dangerous goods for personal use.
Flights under Part 91 include:
Aircraft flying under Part 91 must still follow important safety rules. They need to have annual inspections and be kept in good shape, following the manufacturer's instructions. But unlike airlines or charter companies, they don't need special FAA-approved maintenance programs.
Part 91 is the foundation for all U.S. flight rules. Even if a pilot later flies under stricter rules (like Part 135 or 121), they must still understand and follow Part 91. Whether you're flying for fun or training for a job, these rules apply to everyone.
Part 91 sets the basic rules for who can fly an aircraft under general aviation. These rules focus on what kind of license the pilot has, their health, and how recently they have flown.
To fly under Part 91, a pilot must have at least a private pilot certificate that matches the type of aircraft they want to fly. Some planes also need extra training, like for flying in clouds (IFR), using complex systems, or flying faster planes.
Pilots also need a valid medical certificate. The type depends on the pilot's age and what kind of flying they do. If the medical certificate has expired, they can't fly.
To carry passengers:
Every pilot also needs a flight review every 24 months with a flight instructor. This keeps their skills sharp and helps them stay up to date with FAA rules.
Even though Part 91 rules are more flexible than airline rules, they still require pilots to stay trained, healthy, and legal.
Understanding how Part 91 compares to Parts 121 and 135 is important for staying legal and safe. These FAA rules apply to different types of flying. Knowing which one fits your operation can help you avoid mistakes, fines, or grounded aircraft.
Part 121 governs scheduled air carriers like major airlines, which handle over 20 million people during the week of Thanksgiving.
Here's how it's different from Part 91:
Part 91 doesn't need dispatchers or advanced systems. It has fewer checks and more freedom—but also more personal responsibility for the pilot and operator.
Part 135 covers charter and on-demand flights, like private jets for hire or air taxis. It's stricter than Part 91 but not as intense as Part 121.
Here are the key differences:
You can't do paid charter flights under Part 91. If you're flying for money, you need to follow Part 135 rules. Not doing so could lead to legal problems.
While Parts 91, 121, and 135 tell you how to fly based on the type of operation, Part 61 is different. It explains how pilots get their licenses and stay qualified to fly. It does not cover how flights are run—it just focuses on the pilot.
Part 61 sets the rules for becoming a pilot and keeping your license current. These rules apply to all pilots—whether you fly for fun or as a job.
Part 61 covers:
This is important to understand because just having a license under Part 61 does not mean you're allowed to fly under Parts 91, 121, or 135 without following those rules too.
Part 61 tells you who is qualified to fly. The other parts (91, 121, and 135) tell you how and when you can fly. Knowing the difference helps you stay legal and avoid costly mistakes.
The FAA has different rules depending on the type of flight you operate. These rules each come with their own safety standards, recordkeeping needs, and pilot responsibilities. Knowing the differences is important so you can follow the right rules and avoid legal trouble.
Each part has its own rules for keeping maintenance records. Part 91 gives more freedom, but you still must track required inspections.
If your records aren't complete, your aircraft can be grounded—even if it's in perfect shape. That's why many operators use software like SOMA Software to manage their records, schedule inspections, and keep everything organized in one place.
Under Part 91, the pilot in command is in full control of the flight. They decide if the plane is safe to fly, check the weather, and choose whether or not to take off.
In commercial operations like Part 135 or 121, the responsibility is shared. Other people—like dispatchers or control centers—must approve flights and monitor them in progress.
Here's how they compare:
Commercial rules are stricter because they carry paying passengers. More people are involved to make sure flights stay safe.
Flying under the wrong FAA rules can cause serious problems. Some operators make the mistake of using Part 91 when they should be following Part 135 or 121. This might happen when someone is flying passengers for hire but doesn't have the right certification.
If you fly charter or airline-style operations under the wrong part, the FAA can take action against you. They may issue fines, suspend your certificate, or ground your aircraft.
Other problems include:
Using the right tools helps you stay compliant. Software like SOMA Software makes it easier to track maintenance, follow inspection rules, and stay in line with the correct FAA part for your operation. Whether you fly under Part 91 now or plan to move into commercial flights later, having a strong tracking system will help you grow the right way—safely and legally.
Understanding FAA rules is a vital part of flying safely and legally. Whether you fly under Part 91, 135, or 121, you need the right systems to stay on track with inspections, records, and maintenance.
SOMA makes this easier by putting everything in one place. You can track maintenance, check inspection dates, and keep up with FAA rules—all from one simple system. This helps you avoid mistakes and keep your aircraft flying.
Instead of worrying about paperwork or missed deadlines, you can focus on flying. With real-time updates and clear records, you'll always know your aircraft are ready and compliant.
Take control of your aviation operations with SOMA Software. Manage work orders, track maintenance due dates, generate instant reports, and oversee inventory easily, all in one place. Get a quote today!
