14 CFR Part 43 — Maintenance, Preventive Maintenance, Rebuilding, and Alteration

What Is 14 CFR Part 43?

14 CFR Part 43 is the federal regulation that governs maintenance, preventive maintenance, rebuilding, and alteration of civil aircraft, airframes, aircraft engines, propellers, appliances, and component parts. It sets the legal floor for who may work on certificated aircraft, how that work must be performed, and how it must be documented. Every FAA-certificated Aviation Maintenance Technician (AMT) works under Part 43 daily. Violations can result in certificate action, civil penalties, or criminal prosecution — so knowing it cold is not optional.

Scope and Applicability (§ 43.1)

Part 43 applies to civil aircraft certificated under U.S. airworthiness certificates, with certain exceptions such as experimental amateur-built aircraft (unless maintained under a specific repairman certificate) and foreign-registered aircraft maintained under their own country's rules. Check § 43.1 carefully: if an aircraft is not covered, Part 43 still likely applies through another regulatory path.

Who May Perform and Approve Maintenance (§ 43.3)

Section 43.3 lists every category of person authorized to perform or approve maintenance:

• FAA-certificated AMTs (A&P mechanics) may perform and, within their rating, approve work for return to service.
• Certificated repair stations may perform and approve work within their ratings.
• Certificated pilots may perform preventive maintenance on aircraft they own or operate, provided the aircraft is not used in air carrier service.
• Manufacturers may rebuild or alter equipment they manufactured.
• Persons working under the supervision of an AMT may perform (but not approve) maintenance tasks.

The key distinction: performing work and approving it for return to service are two separate acts. Only authorized persons may sign the approval.

Methods, Techniques, and Practices (§ 43.13)

All maintenance must be performed using methods, techniques, and practices acceptable to the FAA. Acceptable data sources include:

• Manufacturer's maintenance manuals and Instructions for Continued Airworthiness (ICA)
• FAA-approved repair data (Supplemental Type Certificates, Engineering Orders)
• FAA Advisory Circulars that are specifically incorporated by reference
• Other methods acceptable to the FAA Administrator

Using unapproved data — a random internet post, a buddy's memory, an outdated manual — is a Part 43 violation. Always verify data currency before beginning work.

Preventive Maintenance (§ 43.3(g) and Appendix A)

Preventive maintenance is a limited list of simple tasks a certificated private pilot or higher may perform on an aircraft they own or operate. Appendix A, Part (c) lists these tasks explicitly (examples: replacing landing gear tires, servicing landing gear wheel bearings, replacing bulbs and fuses). Nothing outside that list qualifies as preventive maintenance, no matter how simple it seems.

Returning Aircraft to Service (§ 43.7)

After maintenance, the approval for return to service must be made by an authorized person. The AMT signs the maintenance record, confirming the work was completed per approved data and the aircraft is airworthy. No signature = the aircraft is not legally returned to service.

Maintenance Record Requirements — The Two Key Sections

§ 43.9 — Content, Form, and Disposition of Maintenance Records (Other Than Inspections)

For any maintenance (other than an inspection required by an inspection program), the record entry must contain at minimum:

1. A description (or reference to data acceptable to the FAA) of the work performed

2. The date the work was completed

3. The name of the person performing the work (if different from the person approving it)

4. If the work was approved for return to service, the signature, certificate number, and type of certificate held by the approving person

§ 43.11 — Content, Form, and Disposition of Maintenance Records (Inspections)

For required inspections (annual, 100-hour, progressive), the entry must contain:

1. The type of inspection and a brief description of the extent of the inspection

2. The date and aircraft total time in service

3. The signature, certificate number, and kind of certificate held by the person approving or disapproving

4. If approved: a statement that the aircraft has been inspected per the inspection type and found airworthy

5. If disapproved: a statement listing the defects found

Memorize these elements — they are tested on the FAA written exam and they are the basis of the record-writing workshop in this lesson.

Appendices — Don't Skip Them

• Appendix A — Major alterations, major repairs, and preventive maintenance (defines what is major vs. minor; governs what data and forms are required)
• Appendix B — Airworthiness limitations (references requirements for recording compliance)
• Appendix C — Large transport category airplanes (supplemental inspection programs)
• Appendix D — Scope and detail of 100-hour and annual inspections (the checklist of systems that must be inspected)

Appendix D is your inspection roadmap. It does not say how to inspect each item — that comes from approved maintenance data — but it defines the scope of every annual and 100-hour inspection.

Safety Considerations

Part 43 is inherently a safety regulation. Key safety habits that support compliance:

• Never return an aircraft to service with known unairworthy conditions. If you find a defect during a 100-hour and it is not corrected, you must record it as a disapproval and ground the aircraft.
• Use current, approved data for every task. Verify revision status before you start.
• PPE and lockout/tagout (LOTO): while performing any maintenance, follow shop safety procedures regardless of regulatory requirements — Part 43 governs records and authorization; OSHA standards and shop safety programs govern the physical hazards of the work.
• Document everything. If it is not written down, it did not happen in the eyes of the FAA.