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Airworthiness Certificate Classification

FAR 21.175 — Airworthiness Certificate Classification

FAR 21.175 explains the two classes of airworthiness certificates—standard and special—and which aircraft categories fall under each. Study guide for pilots.

In Plain English

FAR 21.175 divides airworthiness certificates into two classes: standard and special. Knowing which one your aircraft holds matters because it determines what operations are legal and what limitations apply.

Standard airworthiness certificates are issued to aircraft type certificated in the:

  • Normal, utility, acrobatic, commuter, or transport category
  • Manned free balloon category
  • Special classes of aircraft

Special airworthiness certificates are issued for:

  • Aircraft type certificated in the primary, restricted, provisional, or limited category
  • Aircraft certificated in the light-sport category
  • Aircraft operating for an experimental purpose
  • Aircraft operating under a special flight permit (a.k.a. ferry permit)

Operationally, a standard certificate generally allows broad civil use within the category's limits, while a special certificate carries operating restrictions tied to the certificate's purpose. As pilot in command, you should be able to identify your aircraft's certificate type during preflight and explain its implications.

Regulation Text
14 CFR § 21.175
§ 21.175 Airworthiness certificates: classification. (a) Standard airworthiness certificates are airworthiness certificates issued for aircraft type certificated: (1) In the normal, utility, acrobatic, commuter, or transport category; (2) As manned free balloons; or (3) As special classes of aircraft. (b) Special airworthiness certificates are airworthiness certificates issued for: (1) Aircraft type-certificated in the primary, restricted, provisional, or limited category; (2) Aircraft certificated in the light-sport category; (3) Aircraft operating for an experimental purpose; or (4) Aircraft operating under a special flight permit. [Docket No. FAA-2023-1377, Amdt. 21-109, 90 FR 35205, July 24, 2025]
Oral Exam Questions a DPE Might Ask
Q1What are the two classes of airworthiness certificates, and how do they differ?
Per FAR 21.175, the two classes are standard and special. Standard certificates are issued to aircraft in the normal, utility, acrobatic, commuter, transport, manned free balloon, or special class categories, while special certificates cover primary, restricted, provisional, limited, light-sport, experimental, and special flight permit operations.
Q2Under which class of airworthiness certificate does a light-sport aircraft operate?
FAR 21.175(b)(2) places aircraft certificated in the light-sport category under a special airworthiness certificate.
Q3If an aircraft is being flown on a special flight permit, what type of airworthiness certificate is that?
A special flight permit is a special airworthiness certificate under FAR 21.175(b)(4), issued for aircraft that may not currently meet applicable airworthiness requirements but can be flown safely under specific conditions.
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Related Sections in Part 21
§ 21.1
Certification Procedures
§ 21.101
Type Certificate Changes
§ 21.11
Type Certificate Applicability
§ 21.111
STC Applicability
§ 21.113
Supplemental Type Certificate
§ 21.115
Supplemental Type Certificates
§ 21.117
Supplemental Type Certificates
§ 21.119
STC Privileges
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FAR 21.175 — Airworthiness Certificate Classification