# STC SA1785GL

- Type: Supplemental type certificate
- Status: Current, Reissued
- Holder: USA Jet Airlines Inc., United States
- Description: Installation of a Stage 3 Hushkit on McDonnell Douglas DC-9-31, -32, -32F, -33F, -34, -34F, -41 with:  (1) Pratt & Whitney JT8D-9, -11, -15, -17 series engines
- Applied: May 28, 1991
- Status date: August 1, 2008
- Product: Aircraft, Large Airplane
- Certification basis: Part 21, Part 36
- Data sheets: [TCDS A6WE](https://openairdocs.org/tcds/A6WE)
- Certificate PDF: https://openairdocs.org/files/sha256/6e/74/6e7496ee359614da4f337d4b58fa6cc3b146569e59e09c388cbfee8c3504907f
- Approved model list and other attachments: [SA1785GL_Original.pdf](https://openairdocs.org/files/sha256/12/d6/12d6102293444e1831f80f9178883a54f7b96a48796605d5ff9180747bbd97ab)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/34CFCE09FB16B3D2862574B1006B8C90.0001
- DRS record last changed: December 5, 2025
- Page: https://openairdocs.org/stc/SA1785GL

## ADs that name it (0)

None.

## Approved models (7)

- McDonnell Douglas Corporation DC-9-31 ([TCDS A6WE](https://openairdocs.org/tcds/A6WE))
- McDonnell Douglas Corporation DC-9-32 ([TCDS A6WE](https://openairdocs.org/tcds/A6WE))
- McDonnell Douglas Corporation DC-9-32F ([TCDS A6WE](https://openairdocs.org/tcds/A6WE))
- McDonnell Douglas Corporation DC-9-33F ([TCDS A6WE](https://openairdocs.org/tcds/A6WE))
- McDonnell Douglas Corporation DC-9-34 ([TCDS A6WE](https://openairdocs.org/tcds/A6WE))
- McDonnell Douglas Corporation DC-9-34F ([TCDS A6WE](https://openairdocs.org/tcds/A6WE))
- McDonnell Douglas Corporation DC-9-41 ([TCDS A6WE](https://openairdocs.org/tcds/A6WE))

## 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.

This Certificate issued to USA JET AIRLINES, INC.

**HANGAR 2064 D STREET**

WILLIOW RUN AIRPORT BELLEVILLE, MICHIGAN 48111 Part 4b of the Civil Air Regulations.

A6WE McDonnell Douglas DC-9-31, -32, -32F, -33F, -34, -34F, -41 Description of Type Design Change : Installation of a Stage 3 Hushkit on McDonnell Douglas DC-9-31, - 32, -32F, -33F, -34, -34F, -41 with: (1) Pratt & Whitney JT8D-9, -11, -15, -17 series engines in accordance with ABS Partnership Master Drawing List MDL-009-071-91 dated J une 5, 1992, or later FAA approved revisions; or (2) Pratt & Whitney JT8D -7, -9, -11, -15, -17 series engines operated at JT8D-7 power in accordance with ABS Partnership Master Drawing List MDL-007-003-91, Revision C, dated June 5, 1992, or later FAA approved revisions.

Limitations and Conditions : The installation should not be incorporated in any airplane unless it is determined that the interrelationship between this in stallation and any previous ly approved configuration will not introduce any adverse effect upon the airwor thiness of the airplane. The approval of this modification applies to the above-noted airplane models only. A copy of this STC must be included in the permanent records of the modified airplanes. If th e 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.

(See Page 3 for continuation of Limitation and Conditions)

Date of application : May 28, 1991

Date of issuance : August 25, 1992

Date reissued : March 27, 2002, December 24, 2003 August 1, 2008 Date amended : April 27, 2000, January 25, 2001

( Signature) Manager, Propulsion Branch Los Angeles Aircraft Certification Office (Title)

NOTE:

**DO NOT DELETE THIS PAGE.**

**DO NOT ADD ANY DATA TO THIS PAGE.**

**THIS PAGE IS FOR PAGE NUMBERING PURPOSES, PLEASE DISCARD PRINTED COPY.**

Number SA1785GL

Limitation and Conditions continued:

FAA Approved Airplane Flight Manual Supplement FMS-K5999-091 dated August 25, 1992, or later approved revision is required with this STC for airplanes with JT8D-9, -11, -15, -17 series engines operated at JT8D-9, -11, -15 power.

FAA Approved Airplane Flight Manual Supplement FMS-K5998-091 dated August 25, 1992, or later FAA approved revision is required with this STC for airplanes with JT8D-7, -9, -11, -15, -17 series engines operated at JT8D-7 power.

Noise Compliance: 14 CFR part 36, Stage 3

Engine Intermix: See the applicable AFM supplement

The following instructions for continued airworthiness are applicable to this STC:

• ABS maintenance program supplement, Report Number ABS0325 dated March 16, 1998, or later FAA accepted revision, and

• ABS supplemental maintenance manual, Report Number ABS1219 dated December 19, 1997, or later FAA accepted revision.

-END-

## Every issue (1)

- August 1, 2008: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/6e/74/6e7496ee359614da4f337d4b58fa6cc3b146569e59e09c388cbfee8c3504907f), [SA1785GL_Original.pdf](https://openairdocs.org/files/sha256/12/d6/12d6102293444e1831f80f9178883a54f7b96a48796605d5ff9180747bbd97ab)

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