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Supplemental Type Certificates


For information regarding the supplemental type certificate application process, contact the FAA Aircraft Certification Office (ACO) in your geographic area.  The “Application Guide for Obtaining a Supplemental Type Certificate,” and other related advisory, policy and guidance information is available on the STC Regulations & Policies page.

For information regarding the “One-only” STC application process involving non U.S. registered aircraft, where the U.S. is the State of design, see Order 8110.4, paragraph 4-15c.

STC process - major steps, as required

  • Applicant applies for STC
  • Familiarization and preliminary type certification board (TCB) meetings
  • FAA develops certification program plan
  • Establishment of certification basis by FAA
  • Applicant submits data for approval
  • FAA design evaluation
  • FAA and applicant hold specialists and interim type certification meetings, as required
  • FAA performs conformity inspections
  • Engineering compliance determinations
  • Pre-flight TCB Meeting
  • Applicant performs ground inspections, ground tests, and flight tests
  • FAA reviews manufacturer's flight test results and issues TIA
  • FAA performs conformity inspections, witnesses tests, performs official certification flight tests and flight standards evaluations
  • Functional and reliability testing
  • FAA approves flight manual supplement or supplemental flight manual and holds final TCB meeting
  • AEG completes continuing airworthiness determination
  • FAA issues STC

An STC will be issued only if:

  • the pertinent technical data have been examined and found satisfactory,
  • all necessary tests and compliance inspections have been completed, and
  • the alteration has been found to conform with the technical data.&

An STC will not be issued to:

  • approve minor changes, or for approval of identical replacement parts, unless the installation of such parts constitutes a major change to the type design
  • approve design changes to Technical Standard Order (TSO) approved articles unless the TSO is invalidated for the modified article. An STC which modifies a TSO article must provide for installation
  • combine two or more STCs without additional showing of compliance; or
  • manufacturers or applicants outside of the U.S., except as provided for in a bilateral agreement.

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