8900.1 CHG 486



Section 1  Safety Assurance System: Evaluate and Approve Aircraft Parts, Parts Pool, and Parts Borrowing Authorization

3-3756    REPORTING SYSTEM(S). Use Safety Assurance System (SAS) automation. This section is related to SAS Element 4.7.2 (AW), Aircraft Parts/Material Control.

3-3757    OBJECTIVE. This chapter provides guidance in evaluating and approving aircraft parts, a Title 14 of the Code of Federal Regulations (14 CFR) part 121 parts pool, and a 14 CFR parts 121 and 135 (10 or more) parts borrowing authorization.

3-3758    GENERAL.

A.    Definitions.

1)    Articles. Materials, parts, or appliances.
2)    Operator-Manufactured Parts. Parts manufactured and documented by the operator for use only on that operator’s aircraft. The parts must comply with the original type design and cannot be part of a pool or borrowing agreement.
3)    Parts. Any engine, propeller, component, accessory, material, or hardware used on an air carrier aircraft.
4)    Parts Manufacturer Approval (PMA). PMA parts are parts produced by manufacturers other than the type certificate holder (TCH). These parts must be identical to parts covered under a type certificate (TC), and they must be marked as such. Federal Aviation Administration (FAA) manufacturing inspectors or a manufacturer with PMA authority may approve these parts for use.
5)    Supplemental Type Certificate (STC). When a major change in type design does not require a new application for a TC, an STC is issued. Parts manufactured under an STC are approved under the STC.
6)    Technical Standard Order (TSO). A TSO is a minimum performance standard for specified articles used on civil aircraft and is issued by FAA Engineering. These articles may be used on a variety of equipment items.
7)    Type Certificate (TC). As defined by 14 CFR part 21, 21.41, a TC includes the type design, operating limitations, Type Certificate Data Sheet (TCDS), applicable regulations, and any other conditions or limitations prescribed by the Administrator.

B.    Certification Standards. An operator must ensure that all replacement parts meet or exceed original certification standards. Standard hardware and materials can be used and exchanged without special procedures. When special requirements must be met, accurate documentation must be maintained. Purchase, use, and exchange of parts require special procedures that must be part of the operator’s manual, and in certain circumstances, part of the operator’s operations specifications (OpSpecs).

3-3759    PARTS POOL AGREEMENT AUTHORIZATION. These authorizations apply only to part 121 operators operating outside the United States.

A.    When Operating Under This Authorization. All other provisions for part 121 remain applicable. In addition, part 121, 121.361(b) requires surveillance of the foreign facilities and their procedures to ensure that all work on pooled parts is performed according to the operator’s manuals.

B.    These Authorizations are Approved by Issuance of OpSpecs. The OpSpecs are required only to list those participants (and their locations) inspected by the operator and acceptable to the FAA.

1)    In instances where several U.S.-certificated operators use a foreign facility, the FAA does not object to a participating operator accepting another participating operator’s initial or biennial inspection report, provided the operator’s manual reflects the arrangement.
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2)    Section 121.361 permits deviation allowing the return to service and use of airframe components, powerplants, appliances, and spare parts thereof that have been maintained, altered, or inspected by persons employed outside the United States who do not hold U.S. Airman Certificates. The operator’s OpSpecs authorize this deviation.
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C.    Foreign Facility Inspections.The operator must have in its manual procedures to inspect the parts pooling facilities. The manual also must include procedures to ensure the maintenance of parts according to the operator’s maintenance manuals.


A.    Time Limits. A certificate holder operating under part 121 or part 135, 135.411(a)(2) may be issued OpSpecs to allow it to borrow a part with a higher time since overhaul than authorized, subject to certain conditions and limitations. Since no regulations govern this activity, the OpSpecs must specify that the operator can borrow a part from another operator when the time in service of the available part exceeds the operator’s approved overhaul time limit. The parts, however, cannot exceed the lender’s approved time limits.

B.    Landing Limits. If the number of landings controls the part’s service or overhaul time limit, an operator may borrow and use a part for a maximum of 100 hours or 50 landings when the time in service of the part exceeds the borrower’s approved time limits. The following limitations must be met:

1)    The part must have a minimum of 200 hours or 100 landings (if approved time is controlled by landings) remaining before service or overhaul in the lender’s program.
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2)    The part may not be operated beyond its approved life limit.


A.    Questionable Parts. Under present regulations, the FAA does not have the authority to prevent the sale or use of aircraft parts of questionable serviceability. Although it is the operator’s responsibility to be aware of the possible consequences of using questionable parts on certificated aircraft, the inspector should offer guidance to help prevent possible problems. An operator using a part of unknown quality, condition, or origin must be able to prove conclusively that such parts conform to the provisions of 14 CFR part 43, 43.13.

B.    Proper Maintenance. The operator is responsible for maintaining parts in a condition that ensures the parts continue to meet the original type design. Procedures to ensure this proper maintenance must be part of the operator’s manual.

C.    FAA Approval System. The FAA has a parts manufacturing approval system in effect that allows the FAA to control the sale of reproduction parts. Parts manufactured under this system must display evidence of FAA approval, verifying the origin and serviceability.

D.    Manufacturing Replacement Parts. Repair stations or air carriers may manufacture replacement parts as part of their maintenance program. These parts are acceptable, provided they are manufactured according to acceptable FAA-approved data.

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E.    Replacements from Other Aircraft. Parts, appliances, and components from aircraft that have been involved in accidents or crashes are available to the industry as replacements. Section 43.13 requires that serviceability be ensured before use.

F.    Ex-Military Aircraft. Ex-military aircraft now under civilian TCs create parts problems, particularly when the original manufacturer has ceased production. Certain parts of original manufacture are available for a given aircraft for a number of years after its departure from military status. If original manufacturer fabrication can be substantiated for such parts, they are acceptable, provided they comply with all applicable Airworthiness Directives (AD).

G.    Illegal Parts. Certain parts for ex-military or currently manufactured aircraft are, and have been, scarce. Occasionally, parties other than the original or approved manufacturer produce these parts illegally and offer them for sale. These illegal parts constitute a hazard to flight safety.

H.    Imported Parts. Parts manufactured in foreign countries and supplied to U.S.-certificated operators for use on their aircraft must be imported according to 21.502.

3-3762    COORDINATION REQUIREMENTS. This task requires coordination between the involved Airworthiness inspectors and the operator. Regional coordination may be necessary.


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A.    References (current editions):

    Title 14 CFR Part 21, 21.301 through 21.320.

    Title 14 CFR Part 43, 43.13.

    Title 14 CFR Part 121, 121.361(b) and 121.379.

    Title 14 CFR Part 135, 135.411(a)(2).

    Advisory Circular (AC) 20-62, Eligibility, Quality, and Identification of Aeronautical Replacement Parts.

    AC 43.13-1, Acceptable Methods, Techniques, and Practices—Aircraft Inspection and Repair.

B.    Forms. None.

C.    Job Aids. Automated OpSpecs checklists and worksheets.

3-3764    PROCEDURES.

A.    Review Operator’s Manual for Parts Pool Authorization. Ensure the manual includes:

1)    Procedures to ensure qualified personnel of the operator’s organization perform an initial inspection of the involved foreign facilities. This inspection should ensure that facilities meet the certificate holder’s manual requirements, have properly qualified and trained personnel, and can furnish the parts intended.
2)    Procedures to provide for biennial inspections of the foreign facilities to ensure continued conformity to the operator’s manual in supplying the required parts.
3)    Inclusion of, or reference to, the foreign facilities’ maintenance programs in the operator’s manual, if applicable.
Indicates new/changed information.

B.    Review Operator’s Manual for Parts Borrowing Authorization Procedures.

1)    Ensure the manual includes the following procedures:
a)    Procedures that restrict the overhaul time limits to those authorized by OpSpecs.
b)    Procedures that restrict a remaining minimum time to overhaul to that authorized by OpSpecs.
2)    Ensure the operator has an approved list of authorized vendors, repair stations, and air carriers from which it may borrow parts.

3-3765    TASK OUTCOMES.

A.    Follow the SAS Process to Record This Activity.

B.    Complete the Task. Successful completion of this task will result in issuance of the following OpSpecs:

    OpSpec D081, Parts Pool Agreement Authorization.

    OpSpec D083, Short-Term Escalation Authorization for Borrowed Parts Subject to Overhaul Requirements.

C.    Analyze Results. Follow SAS guidance for Module 5.

3-3766    FUTURE ACTIVITIES. Follow SAS guidance.

RESERVED. Paragraphs 3-3767 through 3-3780.