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.

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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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d. Contract Maintenance Requirements. Sections 121.368 and 135.426 require:

(1) Each certificate holder must be directly in charge of all covered work done for it by a maintenance provider.

(2) Each maintenance provider must perform all covered work in accordance with the certificate holder’s maintenance manual.

(3) No maintenance provider may perform covered work unless that work is carried out under the supervision and control of the certificate holder.

(4) Each certificate holder who contracts for maintenance, preventive maintenance, or alterations must develop and implement policies, procedures, methods, and instructions for the accomplishment of all contracted maintenance, preventive maintenance, and alterations. These policies, procedures, methods, and instructions must provide for the maintenance, preventive maintenance, and alterations to be performed in accordance with the certificate holder’s maintenance program and maintenance manual.

(5) Each certificate holder who contracts for maintenance, preventive maintenance, or alterations must ensure that its system for the continuing analysis and surveillance of the mainte nance, preventive maintenance, and alterations carried out by the maintenance provider, as required by §§ 121.373(a) and 135.431(a), contains procedures for oversight of all contracted work.

(6) The policies, procedures, methods, and instructions required by paragraphs 9-1d(4) and 9-1d(5) must be acceptable to the FAA and included in the certificate holder’s maintenance manual, as required by §§ 121.369(b)(10) and 135.427(b)(10).

(7) Each certificate holder who contracts for maintenance, preventive maintenance, or alterations must provide to its FAA certificate-ho ld i ng district office (CHDO) a list of maintenance providers in a format acceptable to the FAA. This list must include the name and physical (street) address, or addresses, where each maintenance provider performs work for the certificate holder, and a description of the type of maintenance, preventive maintenance, or alteration that is to be performed at each location. The list must be updated with any changes, including additions or deletions, and the updated list provided to the FAA in a format acceptable to the FAA by the last day of each calendar month.

(a) When submitting the maintenance provider list (MPL) required by §§ 121.368(h) and 135.426(h) to the FAA, there are two MPL templates available to air carriers which are acceptable to the FAA: MPL Template-Excel and MPL Template-XML. Both templates can be downloaded from the Flight Standards Service Aircraft Maintenance Divis io n (AFS-300) Web site under the AFS-300 Job Aids section. Two additional MPL informational files are available on the Web site:

1. MPL Import – This document defines field names, descriptions, field length, and other informatio n required to understand the required structure of both of the supported formats.

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2. MPL Informat io n – This document provides informatio n and instructio ns about contractors used by 14 CFR parts 121, 135, 121/135, and 145 in two formats; these formats are Excel and XML.

(b) Once completed, the MPL must be submitted to the air carrier’s FAA CHDO by the last day of each calendar month. The AFS-300 Web site can be found at http://www.faa.gov/about/office_org/headquarters_offices/avs/offices/afs/afs300/.

NOTE: The MPL does not include subcontractors used by the MP. The air carrie r should accept the MP’s subcontractors at the forefront of the contractual agreement and ensure that procedures exist to notify the air carrie r of any future changes.

9-2. RESPONSIBILITY FOR MAINTENANCE PERFORMED BY OTHERS. Consistent with part 121, § 121.1(b), part 135, § 135.1(a)(2), and others, when you use an MP to accomplis h all or part of the maintenance activities on your airplane or its component parts, that MP becomes part of your maintenance organization and falls under your control. Additionally, §§ 121.363 and 135.413 make it clear that you remain primarily responsible for all of the maintenance performed by that MP on your aircraft. You must determine that the MP has the capability to do your work on your behalf, direct their work, and determine that their work was done satisfactorily according to your manual and your standards. Because all work on your aircraft must be performed in accordance with your maintenance manual and your maintenance program, you must also provide the MP with appropriate materia l from your mainte na nce manual for that work. You must ensure that the MP follows the procedures in your manual that you have provided (see subparagraph 3-2c). You should accomplish this through work-in-progress audits while the MP is actually accomplishing the work. Your manual system should accommodate work performed for you by each MP. The policy and procedures portion of your maintenance manual should assign clear authority and responsibilities and outline procedures for your personnel to administer, control, and direct all contract maintenance. You should arrange the technical material that you provide for the use and guidance of the MP. You should have a written contract with anyone performing contract maintenance for you on a continuing basis. This will help ensure that your responsibilities are addressed. In the case of major operations, such as engine, propeller, or airframe overhaul, the contract should include a specification for the work. You should include or reference that specification in your manual system.

9-3. UNSCHEDULED CONTRACT MAINTENANCE PERFORMED AWAY FROM REGULAR FACILITIES. Sometimes, you will need maintena nce performed on your aircraft while it is away from your regular maintenance facilities. You also may need maintenance services on short notice. Your maintenance manual should include procedures for obtaining these services under these unanticipated conditions. You should never use the term “emergency maintenance” to describe short notice, unscheduled maintenance, as such terms imply to your employees and your MPs that the FAA’s regulatio ns and your procedures do not have to be followed. “Emergency” means that a serious situation has occurred unexpectedly, involves a peril to life or property, and demands immediate action. An out-of-commission aircraft parked on an airport ramp could hardly constitute a peril to life or property. You should outline the procedural steps that you will take to control and direct the unscheduled maintenance Par 9-1 Page 39

accomplished by your MP. Unscheduled, short notice requirements for maintenance do not void your responsibility to determine that your MP has the organizatio n, adequate facilities and equipment, competent personnel, and appropriate portions of your manual for the work that needs to be done. These determina t io ns must be made before any MP starts to work on your aircraft. These procedures and method of determination should be in your manual.

9-4. AIRWORTHINESS RELEASE OR AIRCRAFT LOG ENTRY REQUIRED BY §§ 121.709 AND 135.443. For the purposes of contract maintenance, it is important to note that §§ 121.709(b)(3) and 135.443(b)(3) outline specific requirements for the persons authorized to sign an airworthiness release or aircraft log entry. As defined in part 1, § 1.1, a person is an individual, firm, partnership, corporation, company, association, joint stock association, or government entity. Thus, a repair station, as a company, qualifies as a person defined in § 1.1 and can prepare, or cause to be prepared, an airworthiness release or an appropriate entry in the aircraft log. Such a release or aircraft log entry is limited to the work the repair station is rated to perform and actually performs on an aircraft for certificate holders operating under 14 CFR parts 121, 125, and 135. However, in preparing the airworthiness release or aircraft log entry, the person or, in this instance, the part 145 certificated repair station (CRS), must comply with the procedures set forth in the part 121 or 135 certificate holder’s manual for preparing the airworthiness release or aircraft log entry. Because there is no reference to “person” in §§ 121.709(b) or 135.443(b), the “certificate holder” refers not to the repair station, but the part 121 or 135 certificate holder for whom the repair station is performing maintenance. This provision corresponds to the part 121 and 135 certificate holder’s duty under §§ 121.367 and 135.425 to ensure that not only are competent personnel performing maintenance on their fleets, but that each aircraft released to service is airworthy.

a. Log Entry or Airworthiness Release Form. You must designate each individ ual authorized to execute the log entry or Airworthiness Release Form for you by name and occupationa l title. The individ ua l making the log entry or Airworthiness Release Form acts as your authorized agent. He or she certifies that the maintenance was accomplished according to your maintenance manual and maintenance program procedures, and that no known condition exists that would make the aircraft unairworthy. This arrangement does not reduce the responsibility of maintenance personnel to accomplish maintenance functio ns or tasks in accordance with your manual.

b. Proce dure s for Log Entry or Airworthine ss Re le ase Form. Consistent with §§ 121.709(b)(1) and 135.443(b)(1), you must include in your maintenance manual the procedures for making an aircraft Airworthiness Release Form or log entry. Our regulatio ns require you to make a log entry or complete an Airworthiness Release Form before you can operate your aircraft for any reason after you have accomplished any maintenance. You are required to make a log entry or an Airworthiness Release Form. Other than form or format, there is no legal or technical difference between an Airworthiness Release Form and a log entry.

9-5. EVALUATING NEW MAINTENANCE PROVIDERS. Before you can use an MP for the first time, you must determine that the MP candidate complies with pertinent requirements of part 121 subpart L or part 135 subpart J. In most cases, you would conduct an onsite audit. You must demonstrate, through this audit or by some other means, that the MP has an adequate organization, adequate facilities and equipment, competent personnel, and is capable of Par 9-3 Page 40

performing the work consistent with the requirements of your program. You should use a risk assessment process to determine whether to accomplish an onsite audit or not. Your risk assessment should take into account what happens (the failure effect) when the aircraft part or aircraft system that the MP works on fails. If the failure effect is safety, your procedures should mandate an initial onsite audit along with recurrent onsite audits, as well as the posting of a resident employee at the MP’s facilit y, who is assigned audit and oversight duties.

NOTE: Since the failure effect of parts and systems that come under essential maintenance concerns safety, the air carrie r shouldhave robust policies and procedures to qualify, supervise, and control these MPs, which should include onsite audits.

9-6. CONTINUING MAINTENANCE PROVIDER OVERSIGHT. Ensuring that each one of your MPs is in continuo us compliance is a major functio n of your CASS. You should use your risk-based process for establishing a schedule for auditing and inspecting each of your MPs.

Inherent with a risk-based process, you may determine that some of your MPs do not require an onsite audit. Consistent with the “performance” wording of § 121.373 or § 135.431, the audits that you accomplish should be primarily work-in-progress audits that serve to determine that your MPs are followin g your manual. The audits should be accomplished by trained auditors, and the results analyzed by trained analysts. The results of the analysis should permit you to determine each MP’s continuing compliance with part 121 subpart L or part 135 subpart J, as appropriate, and your maintenance program.

9-7. USING A CERTIFICATED REPAIR STATION (CRS) AS ONE OF YOUR MAINTENANCE PROVIDERS.

a. Arrangements for Maintenance. If you decide to exercise your authority under § 121.379 or § 135.437 to make arrangements with other persons to accomplish contract maintenance for you as provided in your manual, you may choose to make these arrangements with an FAA CRS, but these rules do not require you to do so. The scope of your authorization to make arrangements for maintenance is very broad; you can make arrangements for maintenance with any person as that term is defined in 14 CFR part 1, § 1.1, as long as that MP accomplishes your maintenance in accordance with your manual and maintenance program. Although the § 1.1 term “person” include s a CRS, it also includes anyone who does not hold an FAA certification.

b. Part 145 MP. The air carrier regulatory and maintenance program requirements that you would use to qualify an MP that holds a current part 145 repair station certificate are exactly the same as those that you would use for an MP who does not hold a current part 145 repair station certificate; there is no difference. Consistent with § 119.1(c), § 121.1(b), or § 135.1(a)(2), each person, whether certificated or not, that is employed or used by you for any maintenance, preventive maintenance, or alteration of your aircraft is required to comply with the part 121 requirements and your maintenance program requirements, not 14 CFR part 65 or 145 requireme nt s (see paragraph 8-3). Further, your § 121.379(b) or § 135.437(b) authorization to approve your aircraft for return to service after maintenance extends to the work accomplished under your § 121.379(a) or § 135.437(a) authorization to make arrangements with other persons for maintenance.

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CHAPTER 10. PERSONNEL TRAINING

10-1. MAINTENANCE PROGRAM TRAINING REQUIREMENTS. You can find your specific air carrier maintenance training requirements in certain sections of 14 CFR part 121 subpart L and part 135 subpart J. Part 121, § 121.375 and part 135, § 135.433 require you to have a training program that ensures each person (including inspection personnel) who determines the adequacy of work done for you is fully informed about procedures, techniques, and new equipment in use, and is competent to perform his or her duties. There is an additional implied training requirement in part 121 subpart L and part 135 subpart J based on your responsibility to provide competent personnel for the proper performance of your maintenance program. A training program is the logical means for ensuring that maintenance personnel are competent.

FAA regulatio ns allow you to develop a training program that fits your particular needs.

10-2. TYPES OF TRAINING. Some of the possible types of training in your training program are initial training, recurrent training, specialized training, competency-based training, and maintenance provider (MP) training. You should select the appropriate training for your personnel, includ ing your MP personnel, which you should base on an assessment of training needs. This assessment is a reflection of the required knowledge, skills, and ability to properly accomplish a given task or function, and the current capability of those who you would assign a particular task or function.

10-3. INITIAL TRAINING. You should provide initial training right after you hire an employee, or when your existing employees begin to work on new equipment or a new assignment. Your initial training program may include subjects such as employee indoctrination or orientat io n; maintenance department policies and procedures; maintenance recordkeeping and documentation; aircraft systems or ground equipment; specific skills (e.g., avionics, composite repair, aircraft run-up and taxi); skills upgrade; human factors; task-specific training;

hazardous materials (hazmat); or Enviro nmental Protection Agency (EPA) and Occupational Safety and Health Administ rat io n (OSHA) regulat io ns familia r iza t io n. Your init ia l training should also include a competence-based assessment of employees. This evaluates an employee’s previous training and experience and helps identify his or her specific individ ual training needs.

The objective is to provide training that addresses the gap between required competence and the competence an individual already has.

10-4. RECURRENT TRAINING. Recurrent training is education occurring on a repetitive basis. You must provide maintenance personnel with the informatio n and skills necessary to maintain your standard of competence. This training also accommodates the introduction of new aircraft; aircraft modifications; new or different ground equipment; new procedures, techniques, and methods; or other new informatio n. Your recurrent training, although occurring on a repetitive basis, may not adhere to a defined schedule. You should not provide repetitive informatio n in recurrent training unless it is needed to maintain the desired degree of competence. Your recurrent training may include:

• Continuing competency training designed to maintain regulatory and certificate currency requirements.

• Refresher training on a seldom-accomplished task or seldom-used skill.

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• Update training for particular tasks or skills. Update training can include training bullet ins, bullet in board items, self-study tasks, and computer-based instruction (CBI).

• Any other continuing education or training that may not be provided on a defined schedule.

10-5. SPECIALIZED TRAINING. Your specialized training should focus on competence in specific tasks or Areas of Responsibility (AOR), such as Required Inspection Items (RII), borescope, nondestructive testing, or flight control rigging. You might provide this training with initial or recurrent training. You do not need to limit it to maintenance subjects, but instead may include management skills training for new supervisors, computer skills, or other training necessary because of a change in an individual’s duties and responsibilities.

10-6. M AINTENANCE PROVIDER TRAINING. Your training program must provide appropriate information to each employee of a MP about your specific program. The training should include functio n-specific training appropriate to each person’s job assignment or AOR.

You do not need to provide training to MP personnel in areas that do not concern them. For example, training on aircraft log procedures and minimum equipment list (MEL) procedures would not be required for aircraft interior cleaners, but would be required for maintenance personnel assigned to oncall maintenance for you.

NOTE: If your MP has specific types of training for its personnel, you do not need to duplicate that training for those individuals. However, you must ensure your MP actually has provided the training, and that the training meets your own needs and training standards. This could be a Continuing Analysis and Surveillance System (CASS) work-in-prog re ss audit.

10-7. COMPETENCY-BASED TRAINING. Although air carriers historically have provided a specified number of maintenance training hours to ensure employees have the competencies needed for their jobs, studies have shown that it may be better for you to train to a competency-based standard. You do not have to perform this type of training on a defined schedule or for a specific number of hours. Rather, you should test each individ ual to evaluate what training he or she needs, and then use these evaluatio ns to identify those personnel who retain a high level of subject competence and who may not require a particular block of instructio n. Conversely, you also should identify those individ uals who require more training.

Training to competence permits you to tailor training programs to the specific requirements of your individ ual maintenance personnel and MPs.

a. When to Require Competency-Based Training. You could use competency-based training to raise an employee’s level of competence to that level required by the individual’s duties and responsibilities. You should have procedures to determine when an individual requires competency-based training. You may determine the nee d for this type of training through pre- or post-employment testing, or through the analysis and corrective action functio ns of your CASS.

If you use competency-based training, it should specifically address the lack of competence. In some instances, competency-based training may consist of an appropriately knowledgeable person simply reviewing procedures with an employee through on-the-job training (OJT). You should design competency-based training to fix an immed iate knowledge or skill deficie nc y, and Par 10-4 Page 44

the training may focus on one individ ual or a small group. You may include competency-based training in your initial or recurrent training requireme nts.

b. Com petency Deficiencies. For those circumstances where you identify a competency deficiency through the investigatio n of an event, your competency-based training should show an individual what happened, why it happened and demonstrate, in a positive manner how to prevent it from happening again.

c. Competency Improvement Training. You should orient your competency improvement training toward correcting personnel competence deficiencies that you have identified through your CASS.

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