Navigating FARs: Essential Regulatory References for Aircraft Inspections
For any aircraft owner, operator, or aviation mechanic, a thorough understanding of the Federal Aviation Regulations (FARs) is not just beneficial, it’s absolutely critical. These regulations, specifically Title 14 of the Code of Federal Regulations (14 CFR), are the backbone of aviation safety in the United States, dictating everything from aircraft design to operational rules and, most importantly for us, maintenance and inspection requirements.1 Adhering to these legal foundations ensures airworthiness, which is paramount for the safety and longevity of your single-engine or twin-piston aircraft.
THE CORE OF AIRCRAFT INSPECTIONS: FAR PARTS 91 AND 43
When it comes to routine aircraft inspections, two FAR parts stand out as the primary guides: Part 91, “General Operating and Flight Rules,” and Part 43, “Maintenance, Preventive Maintenance, Rebuilding, and Alteration.”
Part 91, Subpart E, outlines the general requirements for aircraft inspections.2 For most privately operated single-engine and twin-piston aircraft, the annual inspection is a non-negotiable requirement. This comprehensive inspection must be performed every 12 calendar months by a mechanic holding an Inspection Authorization (IA).3 Furthermore, aircraft used for “hire” (such as flight instruction or carrying passengers for compensation) are also subject to a 100-hour inspection, which must be completed within the preceding 100 hours of time in service. It’s important to note that the 100-hour inspection can serve as an annual inspection if all the requirements of an annual are met.
Part 43 provides the detailed instructions and standards for how maintenance, preventive maintenance, rebuilding, and alterations must be performed.4 Appendix D to Part 43 is particularly significant, as it lays out the “Scope and Detail of Items (as Applicable to the Particular Aircraft) To Be Included in Annual and 100-Hour Inspections.”5 This appendix acts as a comprehensive checklist, guiding mechanics through the inspection of various aircraft components, from the airframe and powerplant to the landing gear, empennage, and all associated systems. This ensures a consistent and thorough examination of the aircraft’s condition.
UNDERSTANDING ANNUAL AND 100-HOUR INSPECTIONS
The annual inspection, as defined in FAR 91.409(a), is a complete and thorough inspection of the aircraft.6 It must cover all aspects outlined in Part 43, Appendix D. This is not a superficial check; it often involves opening up access panels, fairings, and cowlings to allow for a detailed examination of internal structures, wiring, control systems, and engine components. For single-engine aircraft like a Cessna 172 or Piper Archer, or twin pistons such as a Beechcraft Baron or Cessna 310, this means a rigorous inspection of every system to ensure it meets airworthiness standards.
Similarly, the 100-hour inspection (FAR 91.409(b)) follows the same scope and detail as an annual inspection, differing primarily in its applicability to aircraft used for hire.7 While a privately owned aircraft not used for hire only requires an annual inspection, an aircraft providing flight training or carrying paying passengers will need both an annual and a 100-hour inspection (or a 100-hour that meets the annual requirements) to remain compliant. The 100-hour limitation can be exceeded by up to 10 hours if the aircraft is en route to a place where the inspection can be performed, but this excess time must be accounted for in the next 100-hour interval.8
MANUFACTURER’S RECOMMENDATIONS AND AIRWORTHINESS DIRECTIVES
Beyond the general FARs, specific manufacturer’s maintenance manuals and Instructions for Continued Airworthiness (ICAs) provide crucial, model-specific guidance for inspections.9 For aircraft powered by Lycoming engines, for instance, Lycoming publishes service bulletins and service letters that, while often advisory for Part 91 operators, may contain important recommendations for maintaining engine longevity and performance.10 Similarly, aircraft manufacturers like Textron Aviation (Cessna, Beechcraft) and Piper Aircraft provide detailed maintenance schedules, progressive inspection programs, and service information that complement the FARs.11
It’s also vital to comply with Airworthiness Directives (ADs) issued by the FAA. ADs are legally enforceable regulations that address unsafe conditions in aircraft, engines, propellers, or accessories.12 They often mandate specific inspections, repairs, or replacements within a certain timeframe or at a particular operating hour. Failure to comply with an applicable AD renders an aircraft unairworthy, regardless of its compliance with other inspection requirements.
THE AERO CENTER ADVANTAGE: REDUCING DOWNTIME
Understanding and navigating these complex regulations requires expertise and dedication. At The Aero Center, we specialize in servicing single-engine and twin-piston aircraft, ensuring full compliance with all FARs, manufacturer’s specifications, and Airworthiness Directives. Our team of experienced aviation mechanics is intimately familiar with the inspection requirements for all major piston aircraft, including those from Lycoming, Continental, Cessna, Piper, and Beechcraft.
We proudly serve all of California, Arizona, and Nevada, bringing unparalleled aviation maintenance services to a wide region. We understand that aircraft downtime can be costly and disruptive, which is why The Aero Center operates as the only 24/7 aviation maintenance center in the area. This round-the-clock availability significantly reduces downtime for your aircraft, getting you back in the air safely and efficiently. Whether it’s a scheduled annual inspection or an unexpected repair, our commitment to prompt and expert service means less time on the ground and more time in the sky.
FOOTNOTES
- Federal Aviation Administration. Title 14 Code of Federal Regulations (CFR) Part 91: General Operating and Flight Rules.13 Available at: https://www.ecfr.gov/current/title-14/chapter-I/subchapter-F/part-91
- Federal Aviation Administration. Title 14 Code of Federal Regulations (CFR) Part 43: Maintenance, Preventive Maintenance, Rebuilding, and Alteration.14 Available at: https://www.ecfr.gov/current/title-14/chapter-I/subchapter-C/part-43
- Federal Aviation Administration. Appendix D to Part 43—Scope and Detail of Items (as Applicable to the Particular Aircraft) To Be Included in Annual and 100-Hour Inspections. Available at: https://www.ecfr.gov/current/title-14/chapter-I/subchapter-C/part-43/appendix-Appendix%20D%20to%20Part%2043
- Federal Aviation Administration. Airworthiness Directives (ADs). Available at: https://www.faa.gov/regulations_policies/airworthiness_directives/
The Aero Center is located at William J. Fox Airfield KWJF | Lancaster, CA.. Contact us at 209.885.6950 for any questions or to schedule an appointment.