AC 120-16G

Advisory circular · Air Carrier Maintenance Programs

Approved
January 4, 2016
Last reviewed
August 6, 2024
Cancels
AC120-16F
Family
AC 120-16 · 6 versions
Revision
G
14 CFR parts
121, 135
14 CFR sections
§ 135.411

Guidance, not mandatory unless a rule or AD requires it. DRS record last changed November 22, 2025.

Show pages 20–31

CHAPTER 8. MAINTENANCE RECORDKEEPING SYSTEM

8-1. REASONS FOR MAKING AND KEEPING MAINTENANCE RECORDS. Your primary reason to make and retain air carrier maintenance records is to show that the U.S. standard airworthiness certificate on your aircraft is effective and that your aircraft is Airworthy. A U.S. standard airworthiness certificate is effective only as long as the maintenance and alterations are performed according to the requirements of the FAA’s regulations. If your required aircraft maintenance records are incomplete or inaccurate, it can render your aircraft’s U.S. standard airworthiness certificate ineffective. Maintenance actions, in almost all cases, become intangible or abstract after the fact. Therefore, in order for you to make a maintenance action tangible, you must make a record of that maintenance action. Additionally, making a record of certain summary informatio n supports identificatio n of the current inspectio n and airworthiness status of your aircraft.

8-2. PART 43 REQUIREMENTS. You can find the basic requirement to make a maintenance record in 14 CFR part 43, § 43.9(a); however, § 43.9(b) indicates that the governing requirements for you, an air carrier, are found in 14 CFR part 121 or 135. That is another way of saying that the recordkeeping requirements of § 43.9(a) do not apply to you. However, the requireme nt s of § 43.9(b) are consistent with the air carrier maintenance recordkeeping requireme nt s of part 121, §§ 121.369(c) and 121.380(a) and (c), or part 135, §§ 135.427(c) and

135.439.

8-3. WORK PERFORMED BY A PART 145 CERTIFICATED REPAIR STATION (CRS).

a. Retaining Records. Title 14 CFR part 145, § 145.219 sets forth requirements for a CRS to retain certain records of maintenance that it performs. It also requires the repair station to make those records available to the FAA. However, these §§ 43.9(a) and 145.219 requirements do not apply when the repair station is accomplis hing any work on your aircraft.

b. Copies of Records. The wording of the § 145.205 regulations, as well as 14 CFR part 119, § 119.1(c), and §§ 121.1(b), and 135.1(a)(2), compel a part 145 CRS to follow the procedures and requirements of your maintenance program and applicable sections of your maintenance manual when accomplishing any maintenance or alterations on your aircraft.

Consequently, a CRS must use the performance standards of part 121 or 135, including the recordkeeping requirements, instead of following the provisions in part 145 and the repair station’s Repair Station Manual (RSM). This is consistent with the requirements of the Paperwork Reduction Act, which does not permit the government to require two separate but identical sets of records. The responsibility for retaining records in accordance with the retention requirements of §§ 121.380(c) and 135.439(b) rests with you, the air carrier, not the repair station. However, if a part 145 repair station wants to retain a copy of those records generated by working on your aircraft, our regulatio ns do not preclude them from doing so. Asking the part 145 repair station to keep your records for you is consistent with regulatio ns, although you are responsible for retaining them and making them available to the FAA. This is consistent with the requirements of § 119.59(c).

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8-4. AIR CARRIER MAINTENANCE RECORDKEEPING.

a. Maintenance Records are Important For:

(1) The air carrier, in fulfilling its responsibility to determine, validate, and maintain the airworthiness status of its aircraft; and

(2) The FAA, for use during a continuing review of aircraft maintenance records as a direct means of determining the airworthiness and safety status of air carrier aircraft.

b. Review ing Maintenance Recor ds. Because reviewing maintenance records is often the only direct means of determining the accomplishment of required maintenance, Federal law treats the act of intentionally failing to make and keep, as well as the act of intentionally falsifying, mutilating, or altering air carrier aircraft records, as a criminal act subject to the imposit io n of substantia l fines and/or impriso nme nt.

8-5. MAKING AND KEEPING REQUIRED RECORDS.

a. Recor dkeeping System . FAA regulatio ns (§ 121.369(c) or § 135.427(c)) require you to have and use a recordkeeping system for the preservation and retrieval of all work performed on your aircraft. You must document your system in your maintenance manual. The primary objectives of these systems are the generation, storage, retention, and retrieval of accurate and complete air carrier aircraft maintenance records. As stated earlier, these records are primarily made to show that the U.S. standard airworthiness certificate of your air carrier aircraft is effective, and that your aircraft is Airworthy and capable of safe flight.

b. Record Locations. FAA regulatio ns (§ 119.59(b)(1)(ii)) also require you to make and keep a listing that identifies the location of each record, document, and report that you are required to make and keep, as well as a listing that identifies each person that is responsible for each of those records, documents, and reports.

c. Airworthine ss Dire ctive s (AD). FAA regulatio ns (§§ 121.380(a)(2)(vii) and

135.439(a)(2)(v)) also require you to keep a record of the current status of applicable ADs, includ ing the date and methods of compliance, and, if the AD involves recurring action, the time and date when the next action is required.

8-6. REQUIRED AIR CARRIER MAINTENANCE RECORDS. Current requirements found in §§ 121.380 and 135.439 call for two types of records: a list of current status infor mat io n, and air carrier airworthiness release form records.

8-7. WHEN TO MAKE RECORDS AVAILABLE TO THE FAA. Section 119.59(c) mandates that you must make your air carrier maintenance records available to us. We can require you to make your records available to us at any time.

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8-8. RESPONSIBILITY FOR MAKING RECORDS AVAILABLE TO THE FAA.

Under § 119.59(b)(1), you must make a list of persons in your organization that you have designated to be responsible for making each required maintenance record, document, or report available to the FAA upon request. You must make a list of the location of each record, document, or report. You must keep this list current and make it available to the FAA at your principal base of operations.

8-9. REQUIRED RECORDS. You are required to make and keep certain current status records. Current status recordkeeping requirements are listed in §§ 121.380 and 135.439 and explained as follows :

a. Total Time in Service. The total time in service of the airframe, each installed engine, and each installed propeller is a record that contains the time in service accrued since new or rebuilt, expressed in hours, landings, or cycles.

NOTE: It is important for you to know that “rebuilt” does not have the same meaning as “overhauled” (§ 43.2(b)).

b. Current Status of Each Life-Limited Part. The current status of each life-limited part of each airframe, engine, propeller, and appliance means a record that contains at least the following information:

(1) Time in service since new, expressed in the appropriate parameter (e.g., hours, cycles, calendar-time);

(2) The time in service remaining to the specified life limit expressed in the appropriate parameter (e.g., hours, cycles, calendar-time);

(3) The specified life limit expressed in the appropriate parameter (e.g., hours, cycles, calendar-time); and

(4) A record of any action that alters the part’s life limit or changes the parameter of the life limit.

NOTE: If you conduct operations under part 135, total time in service and the current status of life-limited parts also includes rotors.

c. Time Since Last Overhaul. The listing of the time since last overhaul means a record that contains at least the following information:

(1) An identification of the item that requires overhaul and its associated scheduled overhaul interval;

(2) The time in service since the last overhaul was accomplished;

(3) The time in service remaining until the next scheduled overhaul is due; and

(4) The time in service when the next scheduled overhaul is due.

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NOTE: The listing of time since last overhaul refers to summary current status information. You must not confuse it with an overhaul record, which is a description of the work performed and the identification of the person who performed and/or issued the approval for re turn to se rvice.

d. Current Inspection Status of the Aircraft. The current inspection status of the aircraft means a record that contains at least the following information:

(1) A listing identifying each of the scheduled inspection packages, and each task and their associated intervals required by the maintenance program under which the aircraft is mainta ined ;

(2) The time in service accrued since the last accomplishment of each of the scheduled inspection packages and tasks required by the maintenance program under which the aircraft is mainta ined ;

(3) The time in service remaining until the next accomplishment of each of the scheduled inspection packages and tasks required by the maintenance program under which the aircraft is maintained; and

(4) The time in service when the next accomplishment of each of the scheduled inspection packages and tasks required by the maintenance program under which the aircraft is mainta ined is due.

e. Current Status of Applicable ADs. The current status of applicable ADs means a record that contains at least the following infor mat io n:

(1) Identification of the particular airframe, engine, propeller, appliance, or component to which the AD applies;

(2) The AD number (and/or regulatory amendment number);

(3) For new ADs, the time when the AD action is due, expressed in the appropriate parameter (e.g., hours, cycles, calendar-time);

(4) The date when the required action was accomplished and the time in service expressed in the appropriate parameter (e.g., hours, cycles, calendar-time);

(5) If the requirement is recurring or not due yet, the date when the next action is due, and the time in service expressed in the appropriate parameter (e.g., hours, cycles, calendar-time); and

(6) With regard to an AD, the method of compliance means a concise description of the action taken to comply with the requirements of the AD. If the AD or its referenced manufacturer’s service bulletin (SB) permits the use of more than one method of compliance, the record must include a reference to the specific method of compliance used. If you use an alternative method of compliance (AMOC) to comply with an AD, the method of compliance means a description of the AMOC and a copy of the FAA approval.

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NOTE: You should not confuse the current status listing of an AD or me thod of compliance with an AD record of accomplishment, which is a description of the work and who performed it and/or issued the approval for re turn to se rvice. They are two separate and distinct records.

f. Current Major Alterations of Each Airframe, Engine, Propeller, and Appliance.

A listing means a record that contains at least the following information:

(1) A listing identifying each major alteration, as well as the associated item that has been altered; and

(2) A description of, or reference to, the FAA-approved technical data that you used to make the major alteration.

NOTE: If you conduct operations under part 135, you must include in this listing all current major repairs, as well as major alterations, and you must include major repairs and major alterations to each rotor.

NOTE: The listing of the current major alterations refers to summary current status information. You must not confuse this with a major alteration report, which is a description of the work performed, a description of the FAA-approved technical data used to make the major alteration, and the identification of the individual who performed and/or issued the approval for re turn to se rvice. You must not confuse this listing with the requirement to submit a copy of each report of a major alteration to the FAA. There are two different requirements—one for a major alteration current status listing, and one for a report for each major alteration that you accomplish.

g. Airworthine ss Re le ase Form. All the records necessary to show that all requirements for the issuance of an Airworthiness Release Form have been met. These records support the use of an Airworthiness Release Form, which is not part of the aircraft maintenance logbook. While the regulatory requirement for these records does not provide a detailed list of these records, this requireme nt is generally accepted to mean:

(1) Detailed records of all scheduled maintenance that has not been superseded by work of equivalent scope and detail;

(2) Detailed records of the last overhaul for items that required an overhaul;

(3) Detailed records of all unscheduled maintenance that has not been superseded by work of equivalent scope and detail; and

(4) Copies of the Airworthiness Release Form covering the last 60 days of operation.

8-10. OTHER REQUIRED RECORDS AND REPORTS. The FAA regulatio ns require you to make other reports and records as discussed in this paragraph. You can use these records and reports to review your maintenance operations to determine the adequacy of the maintenance portion of your air carrier manual and the effectiveness of your CAMP. These records are one of Par 8-9 Page 31

the sources of informatio n for your Continuing Analysis and Surveillance System (CASS). The FAA also uses these reports in its continuo us oversight of your maintenance program activities.

a. Maintenance Log. Sections 121.701 and 135.65 require any person who takes action in response to a reported or observed failure or malfunction to make a record of that action in the maintenance log of the aircraft. These air carrier maintenance log entries correspond to the maintenance recording requirements of § 43.9(b). You also must ensure that each pilot in command (PIC) ensures that all mechanical irregularities occurring during flight time are entered in the maintenance log at the end of that particular flight time, consistent with §§ 121.563 and 135.65.

b. Airworthiness Release Form or Log Entry.

(1) Your Airworthiness Release Form or Log Entry required by § 121.709 or § 135.443 corresponds to the approval for return to service requirements of §§ 43.5, 43.7(e), 121.379(b), and 135.437(b). Furthermore, parts 121 and 135 require you to prepare either an Airworthiness Release Form or a log entry before you can operate your air carrier aircraft after you perform any maintenance, preventive maintenance, or alterations, whether you operate the aircraft in air transportation or not.

(2) Your approval for return to service certification and documentation required by § 121.709 or § 135.443 is a singular requirement, but you may execute it in one of two ways:

(a) You may complete an Airworthiness Release Form and give it to the PIC. If you use an Airworthiness Release Form, you must keep it separate and distinct from the aircraft log.

It is not included in the maintenance record requirements. The separate and distinct requirement corresponds to the requirements in §§ 121.380(a)(1) and 121.709(d). In modern day environments, you are most likely to use the log entry method to comply with § 121.709 or § 135.443. Other than form or format, there is no legal or technical difference between an Airworthiness Release Form and a log entry.

(b) If you make a log entry, you do not have to issue an Airworthiness Release Form. To avoid confusio n and to be consistent with the regulatio ns, you should not identify this entry in the aircraft log as an airworthiness release. We understand that few air carriers use a separate Airworthiness Release Form.

(3) Consistent with §§ 121.709(d) and 135.443(d), you may include a statement in your manual that the signature in the aircraft log of an authorized, appropriately certificated individual constitutes an approval for return to service under your air carrier maintenance program. Such an authorized signature constitutes the four air carrier approvals for return to service certifications without restating each one of the certifications. You must prepare your Airworthiness Release Form or log entry in accordance with procedures in your manual and must include the following four certificatio ns consistent with statutory consideratio ns for operations with the highest degree of safety in the public interest:

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(a) The work was performed in accordance with the requirements of your manual;

(b) All items required to be inspected were inspected by an authorized person who determined the work was satisfactorily completed;

(c) No known conditio n exists that would make the aircraft unairworthy; and

(d) So far as the work performed is concerned, the aircraft is in condition for safe operation.

(4) The Airworthiness Release Form or log entry must be signed by an appropriately certificated individual who is authorized by you to make the Airworthiness Release Form or log entry on your behalf.

NOTE: The Airworthine ss Release Form or log entry must be accomplished by an authorized mechanic or repairman on your behalf under your part 121 or 135 certificate authorizations. This is consistent with the requirements and authorizations of § 43.7(e), 121.379(b), or 135.437(b), and § 121.709(b)(3) or 135.443(b)(3).

NOTE: Consistent with regulations, no individual may issue an Airworthine ss Re le ase Form or make a maintenance log entry unless you have authorized them.

(5) Your maintenance manual should include detailed procedures for accomplishing the Airworthiness Release Form or log entry after you accomplish any maintenance on your aircraft.

Your procedures should include processes designed to ensure that you do not operate your aircraft after any maintenance, preventive maintenance, or alteration is accomplished, unless you complete the Airworthiness Release Form or maintenance log entry.

(6) Your maintenance manual should include detailed procedures for qualifying and authorizing each individ ual that you use to accomplish your § 121.709 or 135.443 Airworthiness Release Form or log entry. These procedures should include a positive, readily available means for you to document and transmit the authorizatio n to the individ ual, includ ing the scope and limitations of their authorization.

c. Service Difficulty Reports (SDR). You are required to make SDRs by §§ 121.703 and 135.415. While analysis of these reports can help your CASS identify deficie nc ies within your maintenance program, these reports are also our primary means of gathering information for our Service Difficulty Reporting Subsystem (SDRS).

d. Mechanical Interruption Reports. We require you, under §§ 121.705 and 135.417, to make mechanical interruption reports. These reports document those instances when there is an interruptio n to one of your flights, unscheduled change of aircraft en route, or unscheduled stop or diversion from a route caused by known or suspected mechanical difficulties that are not required to be reported under the SDR reporting requirements of § 121.703. You are also required to report the number of engines that you removed prematurely because of malfunction, failure, or defect, listed by make, model, and the aircraft type in which it was installed. If you Par 8-10 Page 33

operate aircraft with propellers, you must report the number of propeller featherings in flight, listed by type of propeller, and engine and aircraft on which it was installed. You do not need to report propeller featherings for training, demonstration, or flight check purposes. This is a prime indicator of deficiencies in the effectiveness of your maintenance program. Moreover, Root Cause Analys is (RCA) of these events is one of your most useful means of oversight of the level of effective ne ss of your maintenance program.

8-11. REQUIREMENTS FOR REPORTS OF MAJOR ALTERATIONS AND MAJOR REPAIRS.

a. Part 121 Major Repair and Major Alteration Reports. If you conduct operations under part 121, § 121.707 requires you to make a report of each major alteration and major repair. You must submit the major alteration report to us, and you must make the major repair report available to us for inspection. This falls under § 119.59 requirements. In addition, because you are an air carrier, you do not have to use FAA Form 337, Major Repair and Alteration (Airframe, Powerplant, Propeller, or Appliance), to report a major alteration or major repair that you or an MP accomplished.

b. Part 135 Major Repair and Major Alteration Reports. If you conduct operations under part 135, there is no requirement that requires you to submit reports of major alterations or major repairs. However, while a report is not required, the records of aircraft maintenance or alteration are required and you must make them available to us when we ask for them.

NOTE: You should not confuse these alteration and repair reports with the current status listing of major alterations required under part 121 or the current status listing of major repairs and alterations required under part 135.

8-12. REQUIREMENTS FOR HISTORICAL OR SOURCE RECORDS. You do not have to keep historical or source records to prove that your required records, such as current status records that you must make, keep, and make available to the FAA, are true and accurate.

Inherent with the requirements and objectives of your air carrier maintenance program, you must have a system to prepare, store, and retain your required maintenance records; you must monitor that system under your CASS to ensure that you are following your procedures and that they are effective. This ensures that your required records are true and accurate. Records such as the in-service history of life-limited parts (traceability back to birth) or the record of accomplishment of an AD do not need to be kept indefinitely. However, remember there are severe crimina l penalties for falsifying or failing to make or keep air carrier records. Consistent with FAA regulations, unless there is evidence to the contrary, an aircraft maintenance record produced by your maintenance recordkeeping system should be acceptable by itself, without other historic a l or source records. The important consideration here is that you have a sound and properly working recordkeeping system. You may wish to archive certain source documentation records that you used to introduce parts or components into your maintenance system. These records may include documents such as the manufacturer’s invoice for new parts, export certificates of airworthiness, documentation of a major repair or alteration, or other similar information that may be useful in the future. You may also have business reasons to maintain historical records, but you can keep historical records of your own choice, not because there are regulatory Par 8-10 Page 34

requirements that require you to keep various historical records. The only records that we can legally require to you to make, retain, and produce for our review are those records that we have clearly outlined in 14 CFR.

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CHAPTER 9. CONTRACT MAINTENANCE

9-1. CONTRACT MAINTENANCE. In the past, many nonregulatory words and terms have been used in the aviation industry to describe a person who performs maintenance, preventive maintenance, and alterations for an air carrier, such as outsource, contract, emergency, vendor, oncall, and maintenance, repair, and overhaul (MRO) facilities. The term contract maintenance means any maintenance, preventive maintenance, or alterations accomplished by a certificate holder’s mainte nance provider. However, the certificate holder always retains primary responsibility for any contract maintenance accomplished by a maintenance provider.

a. Maintenance Provider (MP). Title 14 CFR part 121, § 121.368(a)(1) and part 135, § 135.426(a)(1) define a maintenance provider as any person who performs maintenance, preventive maintenance, or an alteration for a certificate holder other than a person who is trained by and employed directly by that certificate holder.

b. Covered Work. Sections 121.368(a)(2) and 135.426(a)(2) define covered work as any of the following:

(1) Essential maintenance that could result in a failure, malfunction, or defect endangering the safe operation of an aircraft if not performed properly or if improper parts or materials are used;

(2) Regularly schedule maintenance; or

(3) A required inspection item on an aircraft.

NOTE: Essential maintenance is for the Required Inspection Item (RII) of on-wing maintenance. “On-wing maintenance” is to mean the entire aircraft.

In addition, covered work includes both essential maintenance and RIIs, both of which include nonscheduled maintenance. Additionally, other requirements that address both covered work and all other contract maintenance, such as the requirements for air carriers to develop policies, procedures, methods, and instructions for accomplishing all contracted maintenance, necessarily include both scheduled and nonscheduled work.

c. Directly in Charge. Sections 121.368(a)(3) and 135.426(a)(3) define directly in charge as having responsibility for covered work performed by a maintenance provider. A representative of the certificate holder directly in charge of covered work does not need to physically observe and direct each maintenance provider constantly, but must be available for consultatio n on matters requiring instructio n or decision.

NOTE: The term available for consultation may be broadly interpreted.

This allows the air carrier flexibility to use numerous information technology me thods – such as high resolution photographs, text messaging, and the Internet – to acquire the information necessary to make decisions and provide instructions.

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