Whether you own a private jet or plan to charter one, understanding aircraft maintenance is critical. Safety, compliance, and performance all hinge on strict adherence to maintenance regulations and schedules. At Jetvisors, we believe an informed client is a confident client. This guide explains key maintenance categories—A, B, C, and D checks—and outlines the regulatory requirements for private aircraft under Part 91 and charter operations under Part 135 of the Federal Aviation Regulations (FARs).

A, B, C, and D Checks: What They Are

The aviation industry uses a system of progressive maintenance checks:

1. A Check: Performed approximately every 400–600 flight hours or every 200–300 cycles. These are light checks involving filter changes, fluid levels, visual inspections, and minor part replacements.
2. B Check: Less common today but still used by some operators. It falls between A and C checks in terms of depth and is done roughly every 6–8 months.
3. C Check: A more comprehensive inspection conducted every 20–24 months. It requires several days to complete and involves deep system inspections, functional tests, and replacements.
4. D Check: Also called a heavy maintenance visit (HMV). This is a full teardown and rebuild of the aircraft, done every 6–10 years. Aircraft may be out of service for up to two months.

While these checks are commonly referenced in commercial airline maintenance programs, business jet operators often use a phase-based inspection program approved by the FAA or manufacturer, especially under Part 135 operations.

Maintenance Requirements for Private Jet Owners (Part 91)

If you own a private aircraft, your operation likely falls under FAR Part 91, which governs general operating and flight rules. Here’s what you must comply with:

1. Annual Inspection

Every aircraft operated under Part 91 must undergo an annual inspection (§91.409(a)) unless it's on a progressive program. It must be completed by an FAA-certified mechanic with Inspection Authorization (IA).

2. 100-Hour Inspection

If the aircraft is used for hire (such as flight instruction or passenger carriage), it must receive a 100-hour inspection (§91.409(b)). Though private owners don’t typically use their jets “for hire,” any revenue-generating use triggers this requirement.

3. Airworthiness Directives (ADs)

Owners must ensure compliance with Airworthiness Directives, which are legally enforceable rules issued by the FAA to correct unsafe conditions (§91.403(a)).

4. Maintenance Records

Maintenance must be documented per §43.9 and §91.417, including all inspections, repairs, and AD compliance. Aircraft without proper logs cannot legally fly.

Maintenance Under Charter (Part 135)

Aircraft used for air charter services fall under FAR Part 135, which imposes more stringent maintenance and operational oversight.

1. Approved Maintenance Program

Operators must have an FAA-approved maintenance program that may include phase inspections, time-limited component replacements, and detailed inspection intervals (§135.421).

2. Required Inspections

Charter aircraft must undergo:

1. Preflight inspections by pilots
2. Routine and progressive maintenance per §135.411 and §135.419
3. Compliance with manufacturer-recommended schedules and FAA mandates

3. Maintenance Personnel

Work must be completed by certified mechanics, and inspections must be signed off by technicians with IA, or an FAA-approved repair station (§43.3, §135.429).

4. Recordkeeping and Reporting

Under §135.439, operators must keep records of:

1. Total time in service
2. Time since last overhaul
3. Status of life-limited parts
4. Compliance with ADs
5. List of major repairs and alterations

Failure to maintain accurate logs can lead to certificate suspension or civil penalties.

Why This Matters for Charter Clients

If you're chartering a private jet, ensure the operator is compliant with Part 135. Legitimate charter operators must follow rigorous maintenance schedules, ensuring aircraft are in peak condition and meet the highest safety standards.

Ask These Questions:

1. Is the aircraft Part 135 certified?
2. When was the last major inspection?
3. Is the operator’s maintenance handled by an FAA-authorized facility?

If answers aren't clear or documentation isn't available, it’s a red flag.

Conclusion

Aircraft maintenance isn’t just a behind-the-scenes process—it’s the backbone of aviation safety and reliability. Whether you own a jet or charter one, understanding what’s required under Parts 91 and 135 helps you make smarter, safer choices. At Jetvisors, we ensure every aircraft we represent or charter meets or exceeds FAA standards.

References

Federal Aviation Administration. (2024). 14 CFR Part 91 - General Operating and Flight Rules. U.S. Government Publishing Office. https://www.ecfr.gov/current/title-14/chapter-I/subchapter-F/part-91/subpart-E

Federal Aviation Administration. (2024). 14 CFR Part 135 - Operating Requirements: Commuter and On Demand Operations. U.S. Government Publishing Office. https://www.ecfr.gov/current/title-14/chapter-I/subchapter-G/part-135

Gleim Aviation. (2024). FAR/AIM: Title 14, Part 43 - Maintenance, Preventive Maintenance, Rebuilding, and Alteration. https://www.gleim.com/aviation/faraim/index.php?fullTextNum=43

Gleim Aviation. (2024). Title 14 CFR 91.409 - Inspections. https://www.gleim.com/aviation/faraim/index.php?leafNum=91_409