us. Deparrment 

of Transportation 

Federal Aviation 

Administration 

#4”jc/-bfy&/ 

Advisory Oal sll ~7 

Circular 

Subjti:PRODUCTION UNDER TYPE CERTIFICATE Dote: 7/l/82 AC No: 21-6~ 

ONLY Initiated by: &&20() Change: 

1. PURPOSE. -I_ ?his advisory circular provides information concerning Subpart F 

of Federal Aviation Regulations (FAR) Part 21 and sets forth an acceptable 

means, not the sole means, of clwnpliance with its requirements. 

2. CANCELIATION. Advisory Circular 21-6, Production Under Type Certificate 

'Only, dated May 26, 1967. 

3. RELATED FEDERAL AVIATION FBGULATIONS. FAR Part 183 

4. DEFINITIONS. As used herein, the following definitions apply: 

a. Manufacturer. !Ihe holder or licensee of a type certificate, producing 

duplicate products in accordance with FAR Part 21, Subpart F. 

b. Supplier. Any person who furnishes articles or services related to the 

manufacture of type ertificated products. 

c. Article. A material, part, component, assembly or appliance which is 

used in the type certificated product, as specified in the type design data. 

d. Aircraft Certification Office (ACO). l'he office that ministers the 

type certificate and production approval of products in the area where the 

manufacturer is located. 

District Office. 'Ihe FAA Manufacturing Inspection District Office 

(MI;; responsible for the evaluation and the inspection of the manufacturer's 

facilities. 

5. DISCUSSION. This advisory circular covers only those sections of FAR 

Part 21, Subpart F, where further discussion, information, or exmnples muld be 

helpful. The headings of each of the following main paragraphs refers to the 

applicable section of Subpart F. 
AC 214 

a. FAR 21.121 Applicability. The term "production under a 

certificate only" refers to the production of a product by a type 

holder or his licensee without related production certificate. 

711/82 

type 

certificate 

b. FAR 21.123 Production Under Qpe Certificate. 

(1) A manufacturer who has been issued a type certificate (Tc) is 

qiven six months under FAR 21.123(c) to establish and implement a production 

inspection system, unless the manufacturer has applied for a production 

certificate under FAR 21, Subpart G. IXlrinq the six (6) month period from the 

date of issuance of the Tc each completed product or part thereof is subject to 

FAA inspection prior to the issuance of aimrthiness certificates. Because of 

limited monetary and manpower resources, these inspections may be delayed and/or 

very time consuminq, and would normally allow a very low production rate by the 

manufacturer. It is, therefore, to the manufacturer's advantage to develop and 

implement an approvable production inspection system as quickly as possible. As 

the manufacturer's individual fabrication, assembly, and inspection operations 

are found to be in compliance with the requlations, they may be FAA approved on 

a progressive basis. When areas are found to be in compliance, the FAA may 

thereafter reduce its inspection and increase its reliance on the manufacturer's 

production inspect ion system. When the total production inspection system has 

been found in compliance with the regulations, the cognizant AC0 will issue the 

letter of approval of the production inspection system. Subsequent FAA . 

inspections will be for the purpose of surveillance of the approved system to 

determine continued ccmpliance. 

(2) Upon the estblishment of the production inspection system; 

FAR 21.123(d) requires the manufacturer to submit to the FAA a manual that 

describes the system and the means of making the determinations required 

by FAR 21.125(b). ?he local FAA Manufacturing Inspection District Office 

(MIDO) will evaluate the manual to determine whether the contents are 

ad-ate and provide a clear, completed description of the various systems, 

tests, procedures, records, and forms which will be the means for compliance 

with FAR 21.125 through 21.130. When the manual is considered acceptable, the 

district office will conduct a physical inspection of the various areas of the 

production inspection system. 

(3) In the event a manufacturer does not establish and implement a 

production inspection system within six (6) months from the date of issuance of 

the K, the manufacturer may request an extension of the time period when there 

are unusual or extenuating circmstances that muld preclude the establishment 

of the production inspection system. A request for the extension may be made to 

the Regional Director of the Aircraft Certification Directorate. The request 

should include information, views, and argments to substantiate that the reason 

for the extension was unavoidable. If the manufacturer does not establish and 

implement a production inspection at the end of the six (6) month period, and 

there are no extenuating circLanstances to preclude the establishment and 

implementation, the FAA will discontinue inspections until an approvable system 

has been established. 

c. FAR 21.125 Production Inspection System: Materials *view Board. The 

basic requirements for the production inspection system and materials review 

board are generally self-explanatory as outlined in FAR 21.125, and the 

following paragraphs provide an example of acceptable compliance: 

2 Par 5 
7/l/82 AC 21+A 

(1) Materials Review Board. An effective materials review board is 

of primary importance in the functioning of an efficient production inspection 

system since it controls the inspection, identification, rework, and use of 

.damaged or nonconforming articles, including the isolation or scrapping of 

unusable articles. The functions of the board are to determine that: 

(a) Appropriate data is submitted to the FAA for engineering 

approval, when a materials review board decision results in a change to the 

product (reference FAR Part 21, Subpart D). 

(b) Provisions are made for appropriate corrective action to 

preclude recurrences of discrepancies when the nonconforming, or otherwise 

unsatisfactory, articles result fran deficiencies in manufacturing procedures, 

processes, design, or any other condition. 

(c) The records required to be maintained are periodically reviewed 

and evaluated to determine the effectiveness of the corrective action program 

and to reveal problem areas as they arise. 

(2) Suppliers. The system established for control of incoming materials 

and bought or subcontracted parts should provide for inspections and tests of 

such articles at the supplier's facility by the manufacturer, if the articles 

cannot or will not be completely inspected upon receipt at the manufacturer's 

plant. 

(3) Storage and Issuance. A reliable, well-controlled storage and 

issuance system, for articles used in the praluct, is a major factor in 

manufacturing a conforming and safe product. Some of the objectives of such a 

system are to ensure that: 

(a) Articles in storage are adequately protected, segregated, and 

identified; 

(b) Articles subject to deterioration from prolonged storage are 

periodically reinspected and disposed of as required; 

(c) Articles being delivered to, or stored in fabrication or 

shipping areas are protected from damage; 

(d) All applicable design changes are incorporated prior to release 

of stored articles for installation in the product; 

(e) cxlly those articles which are identified as having passed 

canpany inspection are received into and issued from finished stores. 

(4) Processes. !Ihe production inspection system should be designed to 

ensure that each process or related service is performed by trained and 

qualified personnel, and that temperatures, solutions, curing times, or any 

other critical factors and equipment are periodically inspected, and that the 

inspections are documented. 'Ihese processes or related services are 

acccanplished to United States or recognized industry specifications when deemed 

appropriate for the particular application. (kamples: Military specification, 

MIGH-6088, "Heat Treatment of Aluminum Alloys," Federal specification, 

Par 5 3 
AC 21-6~ 7/l/82 

QQ-P-416, "Electra-deposition of Cadmium Plate," Aerospace Material 

specification, AMS 2410, "Silver Plating, Nickel Strike, High Bake," etc.) 

(5) Planning. The following paragraphs provide an example of an 

acceptable means of compliance with FAR 21.125(b)(5), which entails the 

establishment of a planning system that will ensure all required inspections 

and tests are conducted in the proper sequence ,when articles and processes 

are in an inspectable condition, as established by fabrication and inspection 

instructions, shop travelers, check lists, or similar media. Such a planning 

system should provide for the establishment and control of inspection procedures which mid ensure that each article used in the product is inspected for 

conformity to the type design. The production inspection system should provide 

for: 

(a) Classification of design characteristics and related 

manufacturing characteristics of all articles, processes, services, and the 

ccmpleted product, so that the most effective fabrication inspection methods 

and process controls muld be used with respect to critical and major 

characteristics and defects. 

(b) Selection of appropriate inspection methods and plans for 

each classification to assure that all characteristics affecting safety will be 

inspected, and reinspected as required, to assure mnformity to approved design 

data. 

used on 

defects 

methods 

(c) Selection and control of-statistical quality control methods 

noncritical characteristics to assure that any nonconformities or 

which may be in a lot accepted under statistical quality control 

will not result in an unsafe condition in an end product or spare part. 

(6) Inspection Stations. An effective production inspection system 

should provide for inspection stations at each major stage of production, 

maintain data, technical material, and records which may be required in the 

performance of inspections or tests at that particular stage of production. 

!lB ensure that all articles, processes, procedures, and the complete products 

are properly inspected, it is also normal procedure to employ a sufficient 

n&r of appropriately gualified inspectors to ensure that all required 

inspections can be methodically performed, with no undue pressure arising 

because of production schedules. 

(7) Inspection Status. Articles will be identified with stamps or 

marks traceable to the individual inspector, properly controlled to ensure that 

only articles which have been inspected and accepted are used in the finished 

product. Ebr example: 

(a) Suitable acceptance, rework, or rejection stamps should be 

placed on articles subjected to processing, testing, and inspection. Such 

stamps should be applied to articles subjected to heat-treating, welding, 

soldering, brazing, bonding, hardness tests, proof testing, laboratory 

analysis, radiographic inspection, ultrasonic inspection, magnetic particle 

inspection, etc. 

(b) Articles which have been reworked and accepted as a result of 

materials review action must be so identified by a suitable stamp. 

Par 5 
7/l/82 AC 21-6~ 

(c) Articles rejected as being unusable or scrap must be plainly 

marked and subseguently controlled so as to absolutely preclude their 

installation on the product or their use as spare parts. 

(8) ?bol and Gauge Control. An important function of a production 

inspection system is to provide for the inspection and the calibration, to 

certified measurement standards, of all inspection tools, gauges, testing 

eguipnent, as well as production jigs, fixtures, templates, etc., which are 

depended upon as media for acceptance. An effective schedule should have the 

inspection intervals established on the basis that such tools and gauges are 

inspected prior to their becoming inaccurate , to ensure timely adjustment, 

replacement, or repair. A record keeping system should ensure that: 

(a) Each piece of equipment is checked prior to first usage and 

at the proper periodic interval, and markd to indicate the date the next 

inspection is due; 

(b) Each piece of eguipTlent is removed from inspection and shop 

areas or conspicuously identified to preclude usage after expiration of the 

inspection due date: and that, 

(c) Calibration standards are traceable to the U.S. National 

Bureau of Standards. 

d. FAR 21.127 Tests: Aircraft. 

(1) Prior to production flight test of aircraft any items coning under 

the provisions of Section 21.127(b)(5) should be checked. For example, it is 

important that: 

(a) !lhe means provided to level the aircraft are accurate and 

in conformity with type design data. 

(b) Each aircraft is weighed to determine that the empty weight 

and center of gravity is in conformity with the type design data. 

(2) The flight test procedure and flight check-off form, required 

to be established and approved under FAR 21.127, should be submitted to the 

FAA Aircraft Certification Office for approval , and may be included in the 

descriptive data discussed under paragraph 5b(2). 

e. FAR 21.128 Tests: Aircraft Engines. 

(1) "Ihe test eguipnent used for the test runs should be capable of 

output determinations of accuracy sufficient to assure that the engine output 

delivered complies with the official ratings and operating limitations. 

(2) Following the tests prescribed by FAF? 21.128, each engine is 

subject to inspection by the FAA to determine that the engine is in condition 

for safe operation. Such inspection may also include internal inspection 

and examination to ensure that no unsafe condition exists. Thedegree of 

internal inspections will normally be determined by the cumulative results 
AC 21-6~ 7/l/82 

of such inspections conducted on the first production engines, and by 

service experiene. The FAA may consider a statistical plan for internal 

engine inspections if the manufacturer submits a proposal based on product 

uniformity, a satisfactory history of previous internal inspections, and 

service experience. 

f. FAR 21.129 Tests: Propellers. - 

(1) An acceptable functional test for variable pitch propellers muld 

include 25 corrq?lete cycles of the control throughout the propeller pitch and 

rotational speed ranges. In addition, for feathering and/or reversing 

propellers, there should be accomplished five cycles of feathering operation 

and five cycles of reversing operation from the lowest normal pitch to the 

maximum reverse pitch. 

(2) Following the functional test, each propeller is subject to 

inspection by the FAA in a similar manner as that described for engines in 

paragraph 5e(2) of this circular. 

9. FAR 21.130 Statement of Conformity. Upon receipt of the statement of 

conform%y, the FAA will inspect the canpleted product to determine that it 

conforms to the type design and is in condition for safe operation. If so, 

an airworthiness certificate will be issued for aircraft, or an Aimrthiness 

Approval Tag, FAA Form 8130-3, will be issued for an engine or propeller. 

h. General. 

(1) Identification of Replacement Parts. Approved replacement parts 

may be identified: 

a. With an FAA Form 8130-3 (Formerly FAA Form 186), Airworthiness 

Approval Tag. An Airworthiness Approval Tag identifies a part or group of 

parts that have been approved by authorized FAA representatives, or 

b. With a shipping ticket, invoice, or other document which 

provides evidence that the part was produced by a manufacturer holding an FAA 

Approved Production Inspection System issued under FAR Part 21, Subpart F. 

c. Such parts produced, which are not accompanied by either of 

the above listed items, are not considered to be FAA approved parts. 

(2) Designated Manufacturing Inspection Representatives. Following 

approval of the production inspection system, the manufacturer may obtain the 

appointment of individuals in his employ as Designated Manufacturing Inspection 

Representatives (DMIR) for the purpose of issuing airworthiness certificates 

and/or aimrthiness approval tags. (Reference FAR Part 183). 

& 

Director of Airworthiness 

4 Par 5