# STC SA235NW

- Type: Supplemental type certificate
- Status: Current, Amended
- Holder: Air Transport Industries, United States
- Description: Modification of cabin compartment irstair door.
- Applied: October 4, 1975
- Status date: June 28, 2006
- Product: Aircraft, Small Multi-Engine
- Certification basis: Part 3, Part 21
- Data sheets: [TCDS A9EA](https://openairdocs.org/tcds/A9EA)
- Certificate PDF: https://openairdocs.org/files/sha256/91/fb/91fb78b3f8a50aab1bdafdf81719f485308e8fbb63e51afb3f92e9e98aa401c9
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/B27B4825D74B3834862571A3006CEA94.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SA235NW

## ADs that name it (0)

None.

## Approved models (4)

- Bombardier Inc. DHC-6-1 ([TCDS A9EA](https://openairdocs.org/tcds/A9EA))
- Bombardier Inc. DHC-6-100 ([TCDS A9EA](https://openairdocs.org/tcds/A9EA))
- Bombardier Inc. DHC-6-200 ([TCDS A9EA](https://openairdocs.org/tcds/A9EA))
- Bombardier Inc. DHC-6-300 ([TCDS A9EA](https://openairdocs.org/tcds/A9EA))

## What the certificate says

Read from the PDF's text layer, without the form's printed wording; the layout is lost and the order can differ. The PDF is the record.

United States of America Department of Transportation_Federal Aviation Administration Supplemental Type Certificate Number SA235NW This certificate, issued to: Air Transport Industries 328 Priest Point Drive NW Marysville, WA 98270

Part 3 of the Civil Air Regulations.

Original Product⎯Type Certificate Number: A9EA Make: DeHavilland Model: DHC-6 Series

Description of the Type Design Change: Installation of a cabin compartment airstair door in accordance with Air Transport Industries Master Drawing List No. 1 revised June 28, 2006 or later FAA approved revision.

Limitations and Conditions: The approval of this change in type design applies basically to the above model aircraft only. This approval should not be extended to other aircraft of this model on which other previously approved modifications are incorporated unless it is determined that the interrelationship between this change and any other previously approved modifications will introduce no adverse effect upon the airworthiness of that aircraft. A copy of this Certificate shall be maintained as part of the permanent records for the modified aircraft.

If the holder agrees to permit another person to use this certificate to alter the product, the holder shall give the other person written evidence of that permission.

Date of application: October 4, 1975 Date reissued:

Date of issuance: November 5, 1975 Date amended: December 23, 1975; January 7, 1980;

June 28, 2006

Original signed by Mike Pasion (Signature) Acting Manager, Seattle Aircraft Certification Office (Title)

## Every issue (1)

- June 28, 2006: Amended, Current. [certificate](https://openairdocs.org/files/sha256/91/fb/91fb78b3f8a50aab1bdafdf81719f485308e8fbb63e51afb3f92e9e98aa401c9)

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