Chapter 9: Regulations, Maintenance Forms, Records, and Publications

Chapter: Regulations, Maintenance Forms, Records, and Publications

Overview

This chapter provides a comprehensive examination of the regulatory framework governing aircraft maintenance in the United States, with particular emphasis on the Code of Federal Regulations (CFR) Title 14, the documentation requirements for maintenance actions, and the responsibilities of certificated maintenance personnel. The material covers the critical intersection between regulatory compliance, airworthiness determination, and proper recordkeeping—three pillars that ensure the continued safety and legal operation of aircraft. Understanding these concepts is fundamental for every Aircraft Maintenance Engineer (AME), as they form the legal and procedural foundation upon which all maintenance activities are built.

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Key Concepts

1. Airworthiness and the Chain of Regulatory Authority

The concept of airworthiness is the central organizing principle of aviation maintenance regulation. An aircraft is considered airworthy when it conforms to its type design and is in a condition for safe operation. This determination rests on a hierarchy of regulatory requirements:

• 14 CFR Part 21 establishes the certification requirements for aircraft and aircraft parts, including the type certificate and the approval of replacement parts.
• 14 CFR Part 43 governs maintenance, preventive maintenance, rebuilding, and alteration of aircraft. It defines who may perform maintenance, what standards must be met, and what records must be created.
• 14 CFR Part 65 certifies airmen, including mechanics (A&P) and repairmen, and defines the privileges and limitations of each certificate.
• 14 CFR Part 91 establishes general operating and flight rules, including inspection requirements and the operational status of installed equipment.

The relationship between these regulations is hierarchical: Part 21 establishes the design standard, Part 43 governs how that standard is maintained, Part 65 ensures the personnel performing maintenance are qualified, and Part 91 dictates the operational conditions under which the aircraft may be flown.

2. Maintenance Personnel Privileges and Limitations

The distinction between an Airframe and Powerplant (A&P) mechanic and an Inspection Authorization (IA) holder is critical to understanding maintenance authority:

A&P Mechanic Privileges:

• Perform and supervise maintenance, preventive maintenance, and alterations
• Approve for return to service any aircraft or component after minor repairs or alterations
• Perform 100-hour inspections and sign them off
• Cannot perform annual inspections or approve major repairs for return to service

Inspection Authorization (IA) Privileges:

• All privileges of an A&P mechanic
• Perform annual inspections and sign them off
• Approve major repairs and major alterations for return to service
• Perform progressive inspections
• Must hold an A&P certificate for at least three years and meet specific experience requirements

The critical limitation is that major repairs and major alterations require final inspection and approval by an IA or an appropriately rated repair station, even if the physical work was performed by an A&P mechanic. This separation of work performance from approval authority ensures independent verification of complex maintenance actions.

3. Classification of Repairs: Major vs. Minor

The classification of a repair determines the documentation requirements and the approval authority needed. 14 CFR Part 43, Appendix A provides the definitive list of what constitutes a major repair or major alteration.

Major Repairs are those that, if improperly done, might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness. Examples include:

• Repair of primary structural components (wing spars, engine mounts, control surfaces)
• Welding of structural components
• Repair of landing gear struts and actuating cylinders
• Major alterations to the fuel system
• Repair of rotor blades on helicopters

Minor Repairs are all other repairs that do not meet the threshold for major classification. Examples include:

• Replacement of control cables
• Replacement of landing gear actuators
• Tire replacement
• Repair of minor cracks in non-structural fairings
• Avionics wiring repairs

The classification is not always intuitive. For example, replacing a landing gear actuator is a minor repair, while welding an engine mount is a major repair. The mechanic must consult Part 43 Appendix A to make the correct determination, as misclassification can lead to regulatory violations.

4. Airworthiness Directives (ADs)

Airworthiness Directives are legally enforceable rules issued by the FAA that apply to specific aircraft, engines, or components. They are issued when an unsafe condition exists and the condition is likely to exist in other products of the same type design.

Key Characteristics of ADs:

• Mandatory compliance: No person may operate an aircraft to which an AD applies unless the AD has been complied with
• Not condition-based: Life limits and compliance times cannot be extended based on the condition of the part
• Types: ADs may require inspections, modifications, parts replacement, or operational limitations
• Repetitive vs. one-time: Some ADs require recurring actions at specified intervals; others are one-time requirements

Documentation Requirements for AD Compliance:

The maintenance record must include:

• The AD number (including amendment or revision)
• The method of compliance
• The date of compliance
• The signature and certificate number of the person performing the work

An aircraft with an overdue or non-compliant AD is not airworthy, regardless of the physical condition of the aircraft. The discovery of a non-compliant AD during an inspection requires that the AD be accomplished before the aircraft can be returned to service.

5. Inspection Requirements

The regulatory framework establishes specific inspection intervals and types:

Annual Inspection (14 CFR 91.409):

• Required within the preceding 12 calendar months
• Must be performed by an IA
• Applies to all aircraft not operating under a progressive inspection program
• The inspection is valid for 12 months from the date of sign-off, regardless of whether the aircraft was operated

100-Hour Inspection (14 CFR 91.409):

• Required for aircraft carrying persons for hire or giving flight instruction for hire
• Must be performed within the preceding 100 hours of operation
• Can be performed by an A&P mechanic
• The inspection interval is based on hours of operation, not calendar time

Preflight Inspection:

• Required before every flight
• Performed by the pilot
• Includes only those items specified in the aircraft's Pilot Operating Handbook

Progressive Inspection:

• An alternative to annual inspections
• Must be approved by the FAA
• Allows the inspection to be broken into smaller segments performed at more frequent intervals

6. Maintenance Record Entries

14 CFR 43.9 establishes the requirements for maintenance record entries. Every maintenance action, preventive maintenance, or alteration must be documented with:

• A description of the work performed (or reference to data acceptable to the Administrator)
• The date of completion
• The signature and certificate number of the person approving the aircraft for return to service

Critical Principles of Record Entries:

• The entry must be made by the person who performed the work or directly supervised it
• Entries cannot be signed by someone who did not perform or supervise the work
• Falsification of maintenance records is a serious violation that can result in certificate action
• Unclear or incomplete entries must be corrected with a new entry that references the original—never by erasing or altering the original
• If a previous entry was made by someone without proper certification, the work must be performed again by a qualified person and documented properly

Return-to-Service Entries:

For inspections, the entry must state that the inspection was performed in accordance with the applicable regulations and that the aircraft is approved for return to service. Any discrepancies found must be listed, and if they affect airworthiness, they must be corrected before the aircraft is returned to service.

7. FAA Form 337

FAA Form 337 (Major Repair and Alteration form) is the official record for major repairs and major alterations. Key requirements include:

• Must be completed for all major repairs and major alterations
• Must be signed by the person performing the work and approved by an IA or repair station
• Must be retained permanently with the aircraft records
• When performed by a repair station, must be submitted to the FAA within 48 hours
• When performed by a mechanic, must be retained with the aircraft records

The form must include a description of the work, the method of compliance, and reference to approved data used. FAA Form 337 is not used for inspections or minor repairs.

8. Inoperative Equipment and Deferred Maintenance

14 CFR 91.213 provides the framework for operating with inoperative equipment:

• If equipment is installed but inoperative, it must be deactivated and placarded "INOPERATIVE"
• A logbook entry must be made documenting the deactivation
• The aircraft may be operated if the inoperative equipment is not required for the type of operation
• If the aircraft has a Minimum Equipment List (MEL), the MEL may provide specific deferral procedures

For example, an inoperative transponder does not affect VFR operations in uncontrolled airspace, but it must be deactivated and placarded. The equipment can remain installed but must be clearly identified as inoperative to prevent inadvertent use.

9. Preventive Maintenance

14 CFR Part 43, Appendix A defines preventive maintenance as simple or minor preservation operations and the replacement of small standard parts not involving complex assembly operations. Examples include:

• Servicing of landing gear wheel bearings
• Replacing safety belts
• Replacing tires
• Replacing spark plugs
• Replacing oil filters (but not tightening a loose oil filter, which is considered maintenance)

A private pilot may perform preventive maintenance on an aircraft they own or operate, but all other maintenance requires certificated personnel. The distinction between preventive maintenance and maintenance is specific, and the list in Appendix A is exclusive—if an action is not listed, it is not preventive maintenance.

10. Approved Data and Acceptable Methods

14 CFR 43.13 requires that maintenance be performed using methods, techniques, and practices acceptable to the Administrator. Sources of approved data include:

• Manufacturer's service manuals and service bulletins
• FAA-approved repair procedures
• AC 43.13-1B (Acceptable Methods, Techniques, and Practices)
• Supplemental Type Certificates (STCs)

Important distinction: Service bulletins are not mandatory unless incorporated into an AD. However, they can serve as approved data for repairs. AC 43.13-1B provides acceptable methods but is not a substitute for manufacturer or FAA-approved data for major repairs. The use of unapproved parts or data is a violation of airworthiness standards.

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Important Regulations and Procedures

Regulatory Reference Summary

Procedures for Common Scenarios

Discovery of Unairworthy Condition During Inspection:

1. Document the condition in the inspection record
2. If the condition affects airworthiness, notify the owner and the FAA in writing
3. Make a logbook entry indicating the aircraft is not airworthy
4. Do not sign the return-to-service entry until the condition is corrected
5. If the condition is minor and does not affect airworthiness, it may be noted as a discrepancy and the aircraft returned to service

Discovery of Non-Compliant AD:

1. The aircraft is not airworthy
2. The AD must be accomplished before the aircraft can be returned to service
3. Document compliance with the AD number, method of compliance, and date
4. Do not return the aircraft to service until compliance is achieved

Correction of Incomplete or Incorrect Records:

1. Do not erase, alter, or remove the original entry
2. Make a new entry that references the original
3. Provide the missing information or correct the error
4. The new entry must include the required information per 14 CFR 43.9

Major Repair by A&P Without IA:

1. The A&P may perform the physical work
2. The repair must be classified as major per Part 43 Appendix A
3. An IA or appropriately rated repair station must perform the final inspection and approval
4. FAA Form 337 must be completed and signed by the approving authority

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Common Relationships Between Concepts

The Airworthiness Equation

Airworthiness = Type Design Conformity + Safe Condition + Regulatory Compliance

This equation demonstrates that an aircraft can be physically sound but still unairworthy if it fails to meet regulatory requirements (such as AD compliance) or if it has been modified with unapproved parts.

Documentation as Proof of Compliance

The maintenance record is the legal evidence that required actions were performed. Without proper documentation, the work is presumed not to have been done. This is why:

• AD compliance must be documented with specific details
• Inspection sign-offs must include the inspection type and result
• Major repairs require FAA Form 337
• All maintenance requires a logbook entry

Authority and Responsibility

The person who signs the maintenance record accepts legal responsibility for the work. This is why:

• Only the person who performed the work (or directly supervised it) can sign
• An A&P cannot sign for work performed by an unqualified person
• Signing for work not performed constitutes falsification
• The approving authority (IA for major repairs) verifies the work meets standards

Inspection and Repair Interdependence

During inspections, discrepancies are often found that require repair. The relationship is:

1. Inspection reveals discrepancy
2. Discrepancy is classified (major or minor)
3. Repair is performed using approved data
4. Repair is documented appropriately
5. Inspection is completed and aircraft returned to service

The inspection cannot be signed off until all discrepancies affecting airworthiness are resolved, but the inspection itself does not need to be restarted after a repair—it can be resumed and completed.

Operational Requirements and Maintenance

The type of operation determines maintenance requirements:

• IFR operations require current altimeter/static system tests (24 months)
• Commercial operations require 100-hour inspections
• VFR-only operations may not require certain equipment to be operational
• The MEL provides deferral options for specific operations

Understanding these relationships is essential for making correct airworthiness determinations and ensuring that maintenance actions are properly documented and approved.