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# What Is Supplemental Type Certificate in Aircraft Maintenance?
- URL: https://www.acmiworld.com/what-is-supplemental-type-certificate-in-aviation/
- Published: 2026-09-16T12:41:08.000Z
- Updated: 2026-09-16T12:41:08.000Z
- Description: Supplemental Type Certificate defined for aviation professionals, with its operational or commercial use, document context and related terminology.
- Author: ACMI World
- Tags: Aviation Glossary, Airworthiness & Maintenance, #Import 2026-09-14 15:41

## Definition, Documents and Application

A Supplemental Type Certificate, or STC, approves a major change to an existing type-certified product by an applicant other than the original type-certificate holder.

Aviation Glossary

**Term:** Supplemental Type Certificate

**Category:** Airworthiness & Maintenance

## Where It Sits in Continuing Airworthiness

Supplemental Type Certificate forms part of the technical framework used to establish, maintain or document aircraft airworthiness. Applicability depends on aircraft type, authority, approved maintenance data and the operator's maintenance programme.

## How It Is Used

Common STCs cover avionics, connectivity, cabin changes, auxiliary fuel, special-mission equipment and other modifications.

## Records and Transaction Impact

Technical status must be supported by current records. Buyers, lessors, lenders and MRO organizations normally verify the applicable document, revision, compliance status and remaining maintenance exposure rather than relying on a description alone.

## Related Aviation Topics

Related ACMI World coverage includes [aircraft maintenance reserves](https://www.acmiworld.com/aircraft-maintenance-reserves-explained-what-airlines-and-lessors-actually-fight-about/), [aircraft redelivery conditions](https://www.acmiworld.com/aircraft-redelivery-conditions-explained-the-hidden-economics-at-lease-end/), [pre-purchase inspection findings](https://www.acmiworld.com/prepurchase-inspection-findings-affect-financing/), [aircraft records and resale value](https://www.acmiworld.com/aircraft-records-affect-resale-value/) and [business jet MRO providers](https://www.acmiworld.com/top-10-business-jet-mro-providers-europe/).

Common STCs cover avionics, connectivity, cabin changes, auxiliary fuel, special-mission equipment and other modifications.

Frequently Asked Questions

## Supplemental Type Certificate FAQ

What does Supplemental Type Certificate mean in aviation?

A Supplemental Type Certificate, or STC, approves a major change to an existing type-certified product by an applicant other than the original type-certificate holder.

Why does Supplemental Type Certificate matter?

Common STCs cover avionics, connectivity, cabin changes, auxiliary fuel, special-mission equipment and other modifications.

Where would an aviation professional encounter Supplemental Type Certificate?

It is commonly encountered in airworthiness & maintenance documents, procedures, calculations or operating discussions where the underlying technical or commercial issue is relevant.

Can technical status be accepted without supporting records?

Normally no. Airworthiness and asset-value conclusions depend on records showing applicability, compliance, release status, accumulated life and maintenance history.