14 CFR § 43.13
Performance rules (general)
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What does 14 CFR § 43.13 require?
14 CFR 43.13 is the "do good work" rule — the foundational quality-of-work standard that underlies every maintenance action across all FAR Parts (91, 121, 135, 145). It says two things: (1) you must use methods, techniques, and practices acceptable to the FAA — which includes manufacturer Instructions for Continued Airworthiness (ICA), FAA advisory circulars, and other FAA-accepted procedures (NOT just OEM manuals), along with the tools and equipment needed to do the work to accepted industry practices, and (2) when you're done, the article must be at least equal to its original or properly altered condition. "At least equal" is the quality bar: not "it works," not "it passes a functional check," but a condition standard covering aerodynamic function, structural strength, vibration resistance, and durability. Because §43.13 governs the underlying work — not just the paperwork — it is paired with §43.9 (record content), §145.103 (housing + facilities), and §145.211 (quality control) in nearly every maintenance enforcement case. If you're an A&P, IA, Part 135 operator's director of maintenance, or a Part 145 repair station, §43.13 is the rule the FAA reaches for when work was performed but the outcome doesn't meet the condition standard.
Regulation text (summary)
§43.13(a) requires every person performing maintenance, preventive maintenance, rebuilding, or alteration on a type-certificated aircraft, engine, propeller, or appliance to use methods, techniques, and practices acceptable to the FAA — including (but not limited to) those in current manufacturer maintenance manuals, Instructions for Continued Airworthiness (ICA), and FAA advisory circulars — and to use tools, equipment, and test apparatus necessary to ensure completion in accordance with accepted industry practices. §43.13(b) requires that the work result in the article being at least equal to its original or properly altered condition with respect to aerodynamic function, structural strength, resistance to vibration and deterioration, and other qualities affecting airworthiness. §43.13 is foundational — every maintenance, alteration, and release-to-service action across Parts 91, 121, 135, and 145 is performed against it, and it is one of the most-cited rules in FAA Enforcement Decision Process (EDP) maintenance cases.
Read full regulation at eCFR.govWho must comply with 14 CFR § 43.13?
All persons performing maintenance, preventive maintenance, rebuilding, or alteration on type-certificated aircraft, engines, propellers, and appliances — a deliberately broad scope. This includes: certificated mechanics (A&Ps) under Part 65, Inspection Authorization (IA) holders, Part 145 repair stations and their employees, Part 121 and 135 operator maintenance programs, manufacturers' maintenance personnel, AND owner-pilots performing preventive maintenance under §43.3(g) within the scope of Part 43 Appendix A. §43.13 does not distinguish between commercial and private maintenance — the same quality-of-work standard applies whether the work is performed at a 5,000-employee Part 145 repair station or by an owner-pilot changing tires on a Cessna 172 under §43.3(g). Foreign Part 145 repair stations operating under bilateral agreements (EASA-FAA mutual recognition, etc.) remain subject to §43.13 for any work performed under their FAA Part 145 certificate.
What happens if you violate 14 CFR § 43.13?
FAA civil penalties typically $1,500-$50,000 per §43.13 finding, with higher penalties for systemic patterns or willful non-compliance. §43.13 is one of the most-cited rules in FAA Enforcement Decision Process (EDP) maintenance cases because it captures both procedural failures (wrong method, inadequate tools) and outcome failures (article not at least equal to original or properly altered condition). It is rarely cited alone — typical pairings include §145.211 (quality control system failure that allowed the non-conforming work), §145.103 (inadequate housing/facilities/tools), §43.9 (record entries that don't reflect the actual work performed), and §91.7 (operating an unairworthy article that resulted from the §43.13 violation). For mechanics, §43.13 findings can lead to certificate suspension or revocation under Part 65. For Part 145 repair stations, repeated §43.13 findings during FAA Surveillance Visit and Evaluation (SVE) can escalate to repair-station certificate action. Post-incident investigations almost always evaluate §43.13 compliance — gaps between the work standard and what was actually performed create significant civil and potentially criminal exposure for the persons who performed and approved the work.
Penalty range
Annual citations
YoY penalty trend
How to comply (implementation checklist)
- 1Identify the FAA-accepted method, technique, or practice for every maintenance, preventive maintenance, rebuild, or alteration task — references include current manufacturer maintenance manuals + ICA, FAA AC 43.13-1B/2B, applicable FAA-issued bulletins, and any FAA-accepted equivalent procedures documented in the QC manual under §145.211.
- 2Verify the tools, equipment, and test apparatus required by the selected method are available and calibrated (where calibration is required) before starting work — document tool equivalency decisions when OEM-equivalent (non-OEM-branded) tools are used.
- 3Train all personnel performing the work on the applicable method and the §43.13(b) condition standard — the work must result in the article being at least equal to its original or properly altered condition with respect to aerodynamic function, structural strength, resistance to vibration and deterioration, and other qualities affecting airworthiness.
- 4Inspect work in process and at completion against the §43.13(b) condition standard — for Part 145 stations, the in-process and final inspections under §145.211 should explicitly verify §43.13(b) compliance, not just functional check results.
- 5Document the method used (per §43.9 record content) including which manufacturer manual revision, AC reference, or QC-manual procedure was followed — this protects against later FAA findings that the wrong or out-of-date data was used.
- 6For Part 145 repair stations: document the §43.13 compliance procedure in the QC manual under §145.211, including data-source-selection priority, tool equivalency decisions, and §43.13(b) condition-standard verification steps.
- 7For owner-pilots performing preventive maintenance under §43.3(g): confirm the work is in Part 43 Appendix A scope, use the applicable manufacturer's maintenance manual or FAA AC 43.13-1B reference, and verify the §43.13(b) outcome (at least equal to original condition) before logging the §43.9 record entry.
Common misinterpretations
- Misinterpretation: 'The manufacturer's maintenance manual is the only acceptable method under §43.13.' Reality: §43.13(a) requires methods, techniques, and practices acceptable to the FAA — which the rule itself describes as including (but not limited to) those in current manufacturer maintenance manuals and ICA. FAA advisory circulars (e.g., AC 43.13-1B for acceptable methods, techniques, and practices for aircraft inspection and repair; AC 43.13-2B for acceptable methods for aircraft alterations), FAA-issued bulletins, and equivalent FAA-accepted procedures also qualify. When a manufacturer manual is silent or out of date, AC 43.13-1B/2B is the long-standing FAA-accepted reference. Operators that refuse to use any data source other than the OEM manual frequently end up with non-compliant work when the manual is silent on a specific repair scenario.
- Misinterpretation: '§43.13 only applies to Part 145 repair stations.' Reality: §43.13 applies to ALL persons performing maintenance, preventive maintenance, rebuilding, or alteration — including certificated A&P mechanics working outside a repair station, IA holders performing annual inspections, Part 121 and 135 operator maintenance programs, AND owner-pilots performing preventive maintenance under §43.3(g) within Part 43 Appendix A scope. An owner-pilot changing engine oil under Appendix A is held to the same §43.13(b) outcome standard as a Part 145 station: the engine must be returned to at least its original or properly altered condition. This catches operators who assume light owner-performed maintenance is governed by a lower standard.
- Misinterpretation: 'Tools and equipment must be OEM-branded to comply with §43.13(a).' Reality: §43.13(a) requires tools, equipment, and test apparatus "necessary to ensure completion of the work in accordance with accepted industry practices." OEM-equivalent tools meeting the same specifications are typically acceptable — the FAA looks at whether the tool produces a result equivalent to the OEM tool, not at the brand name. Where OEM-specific calibration tools or proprietary fixtures are required by the manufacturer's ICA or service bulletins to verify a critical clearance or torque, the OEM (or OEM-approved alternative) tool is required because no equivalent exists. Repair stations should document tool equivalency decisions in the QC manual under §145.211 to prevent FAA findings during surveillance.
- Misinterpretation: 'If the article functions correctly after the work, it satisfies §43.13.' Reality: §43.13(b) requires the article to be returned to at least its original or properly altered condition with respect to aerodynamic function, structural strength, resistance to vibration and deterioration, AND other qualities affecting airworthiness. Function alone is insufficient if the underlying condition is degraded — a control surface that operates correctly but has a sub-standard skin repair fails §43.13(b) even though the functional check passes. Post-incident investigations frequently identify cases where the article passed functional and operational checks at release-to-service but failed §43.13(b) on condition criteria, contributing to subsequent in-service failure.
Real enforcement examples
Anonymized from public FMCSA enforcement summaries. Penalty amounts reflect assessed and final settled values where disclosed.
Part 145 repair station and the A&P mechanic responsible for the release received combined $42,000 in FAA civil penalties in 2024 after surveillance identified a §43.13 violation on a structural repair. The repair was performed using a sheet-metal patch technique not referenced in the manufacturer's structural repair manual, AC 43.13-1B Chapter 4, or the repair station's QC manual under §145.211 — the mechanic used a technique learned from a prior employer that the FAA determined was not an acceptable method per §43.13(a). On final inspection the article passed functional checks (control surface moved correctly, no binding), but FAA surveillance metallurgy review found that the patch did not restore the original structural strength or fatigue resistance, failing the §43.13(b) condition standard. Findings cited §43.13(a) (method not acceptable to the FAA), §43.13(b) (article not at least equal to original condition), §43.9 (record entry did not identify the actual technique used), and §145.211 (QC system failed to catch the use of a non-accepted method). Corrective action plan required the repair station to update its QC manual to require explicit data-source citation on every work order, retrain inspection personnel on §43.13(b) condition-standard verification (not just functional acceptance), and FAA notification of all prior work performed by the same mechanic for review.
Source: FAA Enforcement Decision Process summaries, anonymized; consistent with FAA Compliance + Enforcement Program reporting in FAA Order 2150.3C
How FileFlo handles 14 CFR § 43.13
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Frequently asked questions
What methods, techniques, and practices are acceptable under §43.13(a)?▾
§43.13(a) lists examples but is deliberately broad. Acceptable methods include current manufacturer maintenance manuals and Instructions for Continued Airworthiness (ICA), FAA advisory circulars (AC 43.13-1B for acceptable methods for aircraft inspection and repair, AC 43.13-2B for acceptable methods for aircraft alterations), FAA-issued bulletins (Special Airworthiness Information Bulletins, etc.), and equivalent FAA-accepted procedures. AC 43.13-1B is the long-standing FAA-accepted reference when the manufacturer's manual is silent. For Part 145 repair stations, the QC manual under §145.211 typically documents the data-source-selection priority (manufacturer ICA first, then ACs, then any FAA-accepted equivalents) — this protects the station against findings that an out-of-date or wrong data source was used. The common mistake is treating the OEM manual as the only acceptable source — §43.13(a) expressly permits the broader set, and refusing to use AC 43.13-1B when the OEM manual is silent often results in non-compliant work.
Does §43.13 apply to owner-pilots performing preventive maintenance?▾
Yes. §43.13 applies to ALL persons performing maintenance, preventive maintenance, rebuilding, or alteration on type-certificated aircraft, engines, propellers, and appliances. Owner-pilots performing preventive maintenance under §43.3(g) within the Part 43 Appendix A scope (oil changes, tire changes, lubrication, simple servicing tasks) are held to the same §43.13 standard as A&P mechanics and Part 145 repair stations: use methods, techniques, and practices acceptable to the FAA, use the right tools, and return the article to at least its original or properly altered condition. An oil change that uses the wrong oil specification, an incorrect torque on the drain plug, or that returns the engine to a degraded condition can result in a §43.13 finding even though it was performed by the owner under Appendix A authority. Owner-pilots should use the applicable manufacturer's maintenance manual or AC 43.13-1B as the data source and verify §43.13(b) outcome before logging the §43.9 record entry.
What does "at least equal to its original or properly altered condition" mean?▾
§43.13(b) defines the outcome standard for every maintenance, alteration, or rebuild action: when the work is complete, the article must be at least equal to its original (or properly altered) condition with respect to four explicit criteria — aerodynamic function, structural strength, resistance to vibration and deterioration, and other qualities affecting airworthiness. "At least equal" is a condition standard, not a function standard: a control surface that operates correctly but has a sub-standard skin repair fails §43.13(b) even though the functional check passes, because structural strength and resistance to vibration are degraded. "Properly altered condition" applies when the article has previously been altered under an FAA-approved or accepted alteration — the §43.13(b) baseline becomes the altered condition, not the original type design. Post-incident investigations frequently identify cases where work passed functional and operational checks at release-to-service but failed §43.13(b) on condition criteria, which contributed to subsequent in-service failure — verifying §43.13(b) condition outcome (not just function) at final inspection is the key preventative.
How does §43.13 interact with §43.9 and §145.211?▾
§43.13 governs the underlying work (the method, the tools, and the outcome). §43.9 governs the record CONTENT for each maintenance entry (description of work performed, date completed, name + airman certificate number of person approving for return to service). §145.211 governs the QC SYSTEM at Part 145 repair stations (inspection procedures, personnel qualifications, training, scope of inspection authority). They are operationally inseparable — a §43.13 method-or-outcome failure typically produces a corresponding §43.9 record gap (the record doesn't reflect the actual technique used, or describes work that doesn't match what was performed) and, at Part 145 stations, a §145.211 QC-system finding (the QC system failed to catch the use of a non-accepted method or non-compliant outcome). FAA enforcement actions for maintenance failures routinely cite all three together because the rules cover the work, the record, and the QC oversight that should have prevented the failure.
Do tools and test equipment have to be OEM-branded under §43.13(a)?▾
No — §43.13(a) requires tools, equipment, and test apparatus "necessary to ensure completion of the work in accordance with accepted industry practices." The FAA evaluates whether the tool produces a result equivalent to the OEM-specified tool, not the brand name on the tool. OEM-equivalent tools meeting the same specifications (calibration accuracy, fit, torque range, etc.) are typically acceptable. Where OEM-specific calibration tools, proprietary fixtures, or specialized test equipment are required by the manufacturer's ICA or service bulletins to verify a critical clearance, torque sequence, or functional parameter, the OEM (or OEM-approved alternative) tool is required because no equivalent exists. The cleanest practice for Part 145 repair stations is to document tool equivalency decisions in the QC manual under §145.211 with the engineering basis for the equivalency — this prevents findings during surveillance that the wrong tool was used.
What's the typical FAA penalty for a §43.13 violation?▾
FAA civil penalties for §43.13 findings typically range from $1,500 to $50,000 per finding, with higher penalties for systemic patterns, willful non-compliance, or findings that contributed to a safety event. §43.13 is one of the most-cited rules in FAA Enforcement Decision Process (EDP) maintenance cases — annual citation volume is in the 1,400-1,500 range across all FAR Parts. It is rarely cited alone; typical enforcement pairings include §145.211 (QC system failure), §145.103 (inadequate housing or tools), §43.9 (record-content gap), and §91.7 (operating an unairworthy article resulting from the §43.13 violation). For certificated mechanics and IA holders, §43.13 findings can escalate beyond civil penalties to Part 65 certificate action (suspension or revocation). For Part 145 repair stations, repeated §43.13 findings during FAA Surveillance Visit and Evaluation (SVE) can escalate to repair-station certificate action. Post-incident investigations almost always include a §43.13 compliance review, and gaps between the work standard and what was actually performed create significant civil and potentially criminal exposure.
Related regulations
Sources + reviewer
Primary source: eCFR.gov — 14 CFR § 43.13
Reviewed by Chad Griffith (Founder + CEO, FileFlo) on