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Explanation of Primary Regulations Part 43 (Part One)

Filed Under: Regulations, Maintenance Forms, Records, and Publications

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

Section 43.1—Applicability

Paragraph (a) states quite clearly that aircraft (whether U.S.- or foreign-registered operating under 14 CFR part 121 or 135) and component parts thereof must be maintained in accordance with the rules set forth in this part. Although paragraph b states quite clearly the type of aircraft that this part does not apply to, it seems to have led to considerable confusion within the aviation industry. If an aircraft is flying with a Special Airworthiness—Experimental Certificate (FAA Form 8130-7, Special Airworthiness Certificate—pink color certificate) and that is the only airworthiness certificate this aircraft has ever had, then 14 CFR part 43 does not apply.

Conversely, sometimes during maintenance (especially STC modification—the STC is addressed later in this chapter), it becomes necessary to temporarily place the aircraft into Special Airworthiness—Experimental. This is done to show compliance with federal regulations. These aircraft must still be maintained in accordance with 14 CFR part 43, because the aircraft had a different kind of airworthiness (in this example a Standard) prior to being issued the Special Airworthiness Certificate.

 

Section 43.2—Records of Overhaul and Rebuilding

These terms are not defined in 14 CFR part 1 and are given full explanation in this subpart. Each term states that it may not be used to describe work done on an aircraft, airframe, aircraft engine, propeller, appliance, or component part unless that item has been:

  • Disassembled
  • Cleaned
  • Inspected
  • Repaired, as necessary
  • Reassembled
  • Tested

The key difference between the two terms is in determining how the item is tested. If it is “tested in accordance with approved standards acceptable to the Administration that have been developed and documented by the manufacturer, the item is said to be overhauled.” This is basically another way of describing “service limits,” a term frequently used to describe manufacturer specified acceptable limits for used parts. A “rebuilt item, on the other hand, must be tested to the same tolerances and limits as a new item.”

Section 43.3—Persons authorized to perform maintenance, preventive maintenance, rebuilding, and alterations

There are nine different persons who may perform maintenance: (Reminder: Per 14 CFR part 1, the FAA definition of a person is “an individual, firm, partnership, corporation, association, joint-stock association, or governmental entity. It includes a trustee, receiver, assignee, or similar representative of any of them.”)

  1. Certificated mechanic, per 14 CFR part 65
  2. Certificated repairman, per 14 CFR part 65
  3. Person working under the supervision of a certificated mechanic or repairman
  4. Holder of repair station certificate
  5. Holder of an air carrier certificate
  6. Except for holders of a sport pilot certificate, the holder of a pilot certificate issued under part 61 may perform preventive maintenance on any aircraft owned or operated by that pilot which is not used under 14 CFR part 121, 129, or 135. The holder of a sport pilot certificate may perform preventive maintenance on an aircraft owned or operated by that pilot and issued a special airworthiness certificate in the light-sport category.
  7. Pilot of a helicopter (when operated under 14 CFR part 135 and in remote areas) may perform specific preventive maintenance actions. These actions may only be accomplished under the following conditions:
    • The mechanical difficulty or malfunction occurred en route to or in the remote area.
    • The pilot has been satisfactorily trained and is authorized in writing by the certificate holder to perform the required maintenance.
    • There is no certificated mechanic available.
    • The certificate holder has procedures to evaluate the work performed when a decision for airworthiness is required. The work done is listed in paragraph (c) of Appendix A of this chapter.
  8. Holder of part 135 certificate may allow pilots of aircraft with nine or less passenger seats to remove and reinstall cabin seats and stretchers and cabin mounted medical oxygen bottles. These actions may only be accomplished under the following conditions:
    • The pilot has been satisfactorily trained and is authorized in writing by the certificate holder to perform the required maintenance.
    • The certificate holder has written procedures available to the pilot to evaluate the work performed.
  9. Manufacturer may inspect and rebuild any item it has manufactured.
 

Section 43.5—Approval for return to service after maintenance, preventive maintenance, rebuilding, and alterations

Approving an aircraft component for return to service after maintenance, preventive maintenance, rebuilding, or alteration must be done by creating an appropriate maintenance record entry as required by either 14 CFR part 43, section 43.9 or 43.11. This may include the use of FAA Form 337, Major Repair and Alteration, if the maintenance action was a major repair or a major alteration. Whenever a maintenance action is being planned, it is critical that the technician understands exactly:

  1. What he/she is going to do.
  2. How that work is classified by the FAA.
  3. What type of documentation is required to support this activity.

First consider whether this a repair or an alteration. This should be a relatively simply decision since a repair basically returns the aircraft to its previous or unaltered condition (i.e., replacing magnetos, an exhaust system, tires, or brakes). Even replacing an entire engine (although it is a big job) is still a repair if it is the one properly specified for that aircraft. An alteration on the other hand, always changes or modifies the aircraft from its previous state (i.e., installing winglets, new avionics, or an engine that is not listed in the aircraft TCDS).

The second question to consider is whether or not the work that to be performed constitutes a major or a minor maintenance action. A “major” action is typically one that might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness and that are not done according to accepted practices or cannot be done by elementary operations. This is a much more complex question, but it is extremely important as it drives the final question concerning the substantiating documentation. Please refer to 14 CFR part 1 and part 43, appendix A, for additional clarification and examples.

The third question deals with the type of documentation required to substantiate the work performed. Minor repairs and alterations need only to refer to “acceptable” data, such as manufacturers’ maintenance manuals or AC 43.13-1. The maintenance action can simply be recorded in the maintenance record as a logbook entry. Major repairs and alterations require “approved data.” Some examples of approved data are AD notes, STCs, TCDS, DER-specific delegations, and FAA-approved manufacturer Service Bulletins (SB).

Sometimes the repair or alteration being performed does not have previously-approved data. In that case, the technician may request that the FAA accomplish a “Field Approval.” In this procedure, the technician completes the front side of Form 337 through block 6 (leaving block 3 open for later FAA approval) and then indicates in block 8 on the back what work is to be done and what the substantiating reference data is. Form 337 is then submitted to the local FAA FSDO office for review and approval by an ASI. If necessary, this ASI may seek input from other ASIs or FAA specialists to assist in the review of the data. If the data is found to comply with FAA regulations, the ASI enters one of the following statements in block 3, depending on whether the ASI has performed a review of the data only or has physically inspected the aircraft:

  • “The technical data identified herein has been found to comply with applicable airworthiness requirements and is hereby approved for use only on the above described aircraft, subject to conformity inspection by a person authorized in 14 CFR part 43, section 43.7.”

or

  • “The alteration or repair identified herein complies with the applicable airworthiness requirements and is approved for use only on the above described aircraft, subject to conformity inspection by a person authorized in 14 CFR part 43, section 43.7.”
 

Section 43.7—Persons authorized to approve aircraft, airframes, aircraft engines, propellers, appliances, or component parts for return to service after maintenance, preventive maintenance, rebuilding, or alteration

There are seven different persons listed in this section who may sign RTS documentation:

  1. Certificated mechanic or holder of an inspection authorization (IA)
  2. Holder of a repair station certificate
  3. Manufacturer
  4. Holder of an air carrier certificate
  5. Certificated private pilot
  6. Repairman certificated with a maintenance rating for light sport aircraft (LSA) only
  7. Certificated sport pilot for preventive maintenance on an aircraft owned and or operated by him or her

Note that although a certificated repairman is authorized to work on a product undergoing maintenance, preventive maintenance, rebuilding, or alterations (refer to 14 CFR part 43, section 43.3), he or she is not authorized to approve that product for RTS. He or she must make the appropriate maintenance record entry per the requirements of 14 CFR part 43, section 43.9 or 43.11.

Section 43.9—Content, form and disposition of maintenance, preventive maintenance, rebuilding, and alteration records (except inspection performed in accordance with parts 91 and 125, and sections 135.411(a)(1) and 135.419 of this chapter)

The first observation is that this section specifically excludes inspection entries (those are covered in 14 CFR part 43, section 43.11). This section deals exclusively with maintenance record entries. The next observation is that the list of maintenance actions includes “preventive maintenance.” As stated in the explanation of 14 CFR part 43, section 43.3, a certificated pilot is authorized to perform preventive maintenance on the aircraft he or she owns or operates. Therefore, remember that the pilot must make a record entry of the preventive maintenance he or she has accomplished. There are three distinct issues to be addressed in the maintenance entry and they answer the questions of “what?, when?, and who?”

  • What — a description of the work performed
  • When — the date the work was completed
  • Who
    • — the name of the person who did the work if other than the person who approves the RTS
    • — the signature, certificate number, and type of certificate of the person who is approving the work for RTS

NOTE: Frequently, logbooks have a statement entered that ends something like this: “ … and is hereby returned to service. Joe Fixer A&P, Certificate #123456789.” As this section of the regulation currently reads, that part of the record entry is not required. Title 14 of the CFR part 43, section 43.9 clearly states that “the signature constitutes the approval for return to service only for the work performed.” Furthermore, the technician is only signing off the work he or she has done. Later, 14 CFR part 43, section 43.11 explains that an inspection write-up usually carries a broader scope of responsibility. This section is very clear that the entry completed in accordance with this section only holds the technician responsible for the service maintenance action he or she entered.

If the maintenance accomplished was a major repair or alteration, the work must be documented on FAA Form 337 and requires supporting approved data. If the maintenance action was a major repair and it was done by a certificated repair station, a signed copy of the completed customer work order accompanied by a signed maintenance release may be used in lieu of the FAA Form 337.

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