FAR 21.50 — Continued Airworthiness Instructions
FAR 21.50 requires design approval holders to furnish Instructions for Continued Airworthiness and share airworthiness limitations updates with operators.
In Plain English
FAR 21.50 sets the rules manufacturers must follow to give owners and operators the information needed to keep an aircraft airworthy over its life. While this rule targets type certificate (TC) and supplemental type certificate (STC) holders rather than pilots, it directly affects what maintenance data your mechanic relies on.
Key points:
- Rotorcraft updates: A TC holder for a rotorcraft must share any FAA-approved changes to replacement times, inspection intervals, or related procedures in the Airworthiness Limitations section of the Rotorcraft Maintenance Manual with any operator of that rotorcraft type who requests them.
- ICA delivery: For aircraft, engines, and propellers applied for after January 28, 1981, the design approval holder must furnish at least one complete set of Instructions for Continued Airworthiness (ICA) to the owner at delivery or first standard airworthiness certificate issuance.
- Ongoing access: The holder must make those instructions, and any changes, available to anyone required to comply with them.
- Commercial parts: If the holder designates parts as commercial, a Commercial Parts List with supporting safety data must be submitted to the FAA and included in the ICA.
Why it matters: this rule is why your maintenance shop has access to current manuals, life-limits, and inspection intervals — the foundation of legal airworthiness.
Regulation Text
14 CFR § 21.50§ 21.50 Instructions for continued airworthiness and manufacturer's maintenance manuals having airworthiness limitations sections.
(a) The holder of a type certificate for a rotorcraft for which a Rotorcraft Maintenance Manual containing an “Airworthiness Limitations” section has been issued under § 27.1529 (a)(2) or § 29.1529 (a)(2) of this chapter, and who obtains approval of changes to any replacement time, inspection interval, or related procedure in that section of the manual, must make those changes available upon request to any operator of the same type of rotorcraft.
(b) The holder of a design approval, including either a type certificate or supplemental type certificate for an aircraft, aircraft engine, or propeller for which application was made after January 28, 1981, must furnish at least one set of complete Instructions for Continued Airworthiness to the owner of each type aircraft, aircraft engine, or propeller upon its delivery, or upon issuance of the first standard airworthiness certificate for the affected aircraft, whichever occurs later. The Instructions for Continued Airworthiness must be prepared in accordance with §§ 23.1529, 25.1529, 25.1729, 27.1529, 29.1529, 31.82, 33.4, 35.4, or part 26 of this subchapter, or as specified in the applicable airworthiness criteria for special classes of aircraft defined in § 21.17(b), as applicable. If the holder of a design approval chooses to designate parts as commercial, it must include in the Instructions for Continued Airworthiness a list of commercial parts submitted in accordance with the provisions of paragraph (c) of this section. Thereafter, the holder of a design approval must make those instructions available to any other person required by this chapter to comply with any of the terms of those instructions. In addition, changes to the Instructions for Continued Airworthiness shall be made available to any person required by this chapter to comply with any of those instructions.
(c) To designate commercial parts, the holder of a design approval, in a manner acceptable to the FAA, must submit:
(1) A Commercial Parts List;
(2) Data for each part on the List showing that:
(i) The failure of the commercial part, as installed in the product, would not degrade the level of safety of the product; and
(ii) The part is produced only under the commercial part manufacturer's specification and marked only with the commercial part manufacturer's markings; and
(3) Any other data necessary for the FAA to approve the List.
[Amdt. 21-23, 33 FR 14105, Sept. 18, 1968, as amended by Amdt. 21-51, 45 FR 60170, Sept. 11, 1980; Amdt. 21-60, 52 FR 8042, Mar. 13, 1987; Amdt. 21-90, 72 FR 63404, Nov. 8, 2007; Amdt. 21-92, 74 FR 53386, Oct. 16, 2009; Doc. No. FAA-2015-1621, Amdt. 21-100, 81 FR 96689, Dec. 30, 2016]
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Oral Exam Questions a DPE Might Ask
Q1Who is responsible for providing the Instructions for Continued Airworthiness when you take delivery of a new aircraft?
Per FAR 21.50(b), the holder of the design approval (TC or STC) must furnish at least one complete set of Instructions for Continued Airworthiness to the owner at delivery or upon issuance of the first standard airworthiness certificate, whichever is later.
Q2If a rotorcraft manufacturer changes a replacement time in the Airworthiness Limitations section, are they required to share that change with operators?
Yes. FAR 21.50(a) requires the type certificate holder to make FAA-approved changes to replacement times, inspection intervals, or related procedures in the Airworthiness Limitations section available upon request to any operator of the same rotorcraft type.
Q3What must a design approval holder do to designate a part as a commercial part?
Under FAR 21.50(c), the holder must submit a Commercial Parts List to the FAA, along with data showing the part's failure wouldn't degrade safety, that it's built only to the commercial manufacturer's specs and markings, and any other data the FAA needs to approve the list.
Studying for a checkride?
§21.15 Type Certificate Application
FAA application form, aircraft drawings, and engine data
§21.17 Certification Basis
Applicable airworthiness, noise, and emission rules
§21.20 Compliance Showing
How applicants show compliance to the FAA
§21.31 Type Design
Drawings, specifications, dimensions, and limitations
§21.41 Type Certificate
What the certificate includes once the design is approved
§21.47 Type Certificate Transferability
Transfer and licensing notices for FAA type certificates
Related Sections in Part 21