# STC SA256NW

- Type: Supplemental type certificate
- Status: Current, Amended
- Holder: Williams Robert or Barbara, United States
- Description: Installation of aileron gap seals.
- Applied: November 3, 1975
- Status date: April 12, 1993
- Product: Aircraft, Single-Engine
- Certification basis: Part 21
- Data sheets: [TCDS 3A19](https://openairdocs.org/tcds/3A19), [TCDS A-799](https://openairdocs.org/tcds/A-799), [TCDS 3A12](https://openairdocs.org/tcds/3A12), [TCDS 3A17](https://openairdocs.org/tcds/3A17), [TCDS 5A6](https://openairdocs.org/tcds/5A6), [TCDS 3A13](https://openairdocs.org/tcds/3A13), [TCDS 3A24](https://openairdocs.org/tcds/3A24), [TCDS 3A21](https://openairdocs.org/tcds/3A21)
- Certificate PDF: https://openairdocs.org/files/sha256/1d/db/1ddb78fb1fd2d212453e3f33938c5cf90c0dc89cd4a4c155660a91fc2e1283ec
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/55B42C58BDB5EBF9862579830050922B.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SA256NW

## ADs that name it (0)

None.

## Approved models (85, first 50)

- Cessna Aircraft Company 150 ([TCDS 3A19](https://openairdocs.org/tcds/3A19))
- Cessna Aircraft Company 150A ([TCDS 3A19](https://openairdocs.org/tcds/3A19))
- Cessna Aircraft Company 150B ([TCDS 3A19](https://openairdocs.org/tcds/3A19))
- Cessna Aircraft Company 150C ([TCDS 3A19](https://openairdocs.org/tcds/3A19))
- Cessna Aircraft Company 150D ([TCDS 3A19](https://openairdocs.org/tcds/3A19))
- Cessna Aircraft Company 150E ([TCDS 3A19](https://openairdocs.org/tcds/3A19))
- Cessna Aircraft Company 150F ([TCDS 3A19](https://openairdocs.org/tcds/3A19))
- Cessna Aircraft Company 150G ([TCDS 3A19](https://openairdocs.org/tcds/3A19))
- Cessna Aircraft Company 150H ([TCDS 3A19](https://openairdocs.org/tcds/3A19))
- Cessna Aircraft Company 150J ([TCDS 3A19](https://openairdocs.org/tcds/3A19))
- Cessna Aircraft Company 150K ([TCDS 3A19](https://openairdocs.org/tcds/3A19))
- Cessna Aircraft Company 150L ([TCDS 3A19](https://openairdocs.org/tcds/3A19))
- Cessna Aircraft Company 150M ([TCDS 3A19](https://openairdocs.org/tcds/3A19))
- Cessna Aircraft Company 152 ([TCDS 3A19](https://openairdocs.org/tcds/3A19))
- Cessna Aircraft Company 170A ([TCDS A-799](https://openairdocs.org/tcds/A-799))
- Cessna Aircraft Company 170B ([TCDS A-799](https://openairdocs.org/tcds/A-799))
- Cessna Aircraft Company 172 ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172A ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172B ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172C ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172D ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172E ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172F (USAF T-41A) ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172G ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172H (USAF T-41A) ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172I ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172K ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172L ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172M ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172N ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172P ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172Q ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172RG ([TCDS 3A17](https://openairdocs.org/tcds/3A17))
- Cessna Aircraft Company 175 ([TCDS 3A17](https://openairdocs.org/tcds/3A17))
- Cessna Aircraft Company 175A ([TCDS 3A17](https://openairdocs.org/tcds/3A17))
- Cessna Aircraft Company 175B ([TCDS 3A17](https://openairdocs.org/tcds/3A17))
- Cessna Aircraft Company 175C ([TCDS 3A17](https://openairdocs.org/tcds/3A17))
- Cessna Aircraft Company 180 ([TCDS 5A6](https://openairdocs.org/tcds/5A6))
- Cessna Aircraft Company 180A ([TCDS 5A6](https://openairdocs.org/tcds/5A6))
- Cessna Aircraft Company 180B ([TCDS 5A6](https://openairdocs.org/tcds/5A6))
- Cessna Aircraft Company 180C ([TCDS 5A6](https://openairdocs.org/tcds/5A6))
- Cessna Aircraft Company 180D ([TCDS 5A6](https://openairdocs.org/tcds/5A6))
- Cessna Aircraft Company 180E ([TCDS 5A6](https://openairdocs.org/tcds/5A6))
- Cessna Aircraft Company 180F ([TCDS 5A6](https://openairdocs.org/tcds/5A6))
- Cessna Aircraft Company 180G ([TCDS 5A6](https://openairdocs.org/tcds/5A6))
- Cessna Aircraft Company 180H ([TCDS 5A6](https://openairdocs.org/tcds/5A6))
- Cessna Aircraft Company 180J ([TCDS 5A6](https://openairdocs.org/tcds/5A6))
- Cessna Aircraft Company 180K ([TCDS 5A6](https://openairdocs.org/tcds/5A6))
- Cessna Aircraft Company 182 ([TCDS 3A13](https://openairdocs.org/tcds/3A13))
- Cessna Aircraft Company 182A ([TCDS 3A13](https://openairdocs.org/tcds/3A13))

All 85: https://openairdocs.org/stc/SA256NW/models.md

## What the certificate says

The certificate has no text we could read; open the PDF to read it.

## Every issue (1)

- April 12, 1993: Amended, Current. [certificate](https://openairdocs.org/files/sha256/1d/db/1ddb78fb1fd2d212453e3f33938c5cf90c0dc89cd4a4c155660a91fc2e1283ec)

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