# STC SA3931NM

- Type: Supplemental type certificate
- Status: Current, Reissued
- Holder: Western Skyways Aircraft Modifications Inc., United States
- Description: Installation of air to air intercooler in the engine air induction system.  Airplane must have STC SA2689SW incorporated.
- Applied: March 22, 1988
- Status date: September 18, 2025
- Product: Aircraft, Small Airplane
- Certification basis: Part 23
- Data sheets: [TCDS 3A21](https://openairdocs.org/tcds/3A21)
- Certificate PDF: https://openairdocs.org/files/sha256/b2/e6/b2e6e132be9148985c4ecac53559eca81b3e41135aee1cee94cb69df77df4674
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID107950116620261023145644.0001
- DRS record last changed: October 23, 2026
- Page: https://openairdocs.org/stc/SA3931NM

## ADs that name it (0)

None.

## Approved models (1)

- Textron Aviation Inc. T210L ([TCDS 3A21](https://openairdocs.org/tcds/3A21))

## 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.

SA3931NM Western Skyways Aircraft Modifications Inc.

58784 Spring Creek Road Montrose, CO 81403 Part 3 the Civil Air Regulations.

Effective May 15, 1956 3A21 Textron Aviation, Inc.

1. The approval of this change in type design is limited to the Textron T210L aircraft as modified by STC SA2689SW that is otherwise unmodified.

2. 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.

(Continued on page 3) 3/22/1988 9/6/1996 5/28/2002 8/23/2002 7/21/1988 ✔ for Jason S. Deutschman Acting Manager, Central Certification Branch Compliance & Airworthiness Division Aircraft Certification Service 3 Installation of an air-to-air intercooler in the engine air induction system in accordance with the aircraft portion of Riley International Corp. Master Drawing List (MDL) R15901, Revision N/C, dated June 26, 1988. Supplemental Type Certificate SE3932NM is required as part of this installation. FAA Approved Riley International Corporation Supplemental Airplane Flight Manual No. 2, dated July 18, 1988, or later FAA approved revisions is required.

T210L Incorporating STC SA2689SW

SA3931NM 09/18/26 3

SA3931NM 09/18/26 Date Reissued (continued): 05/20/2019; 03/08/2023; 09/18/2026

3. This approval should not be extended to other engines of this model on which other previously approved modifications are incorporated unless it is determined by the installer that the interrelationship between this change and any of those other previously approved modifications will introduce no adverse effect upon the airworthiness of that engine.

----------------------------------------------------------End----------------------------------------------------- 3 3 Add Page

## Every issue (4)

- September 18, 2025: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/b2/e6/b2e6e132be9148985c4ecac53559eca81b3e41135aee1cee94cb69df77df4674)
- March 8, 2023: Reissued, Historical. [certificate](https://openairdocs.org/files/sha256/91/ef/91efab6b06ed68c554934ca2895b5eee54fd439c76985e6189208956b4a9c55f)
- May 20, 2019: Reissued, Historical. [certificate](https://openairdocs.org/files/sha256/44/7e/447e486986be0c1fff895ebb758da0bffc1526a86d7ad827d52c8656e7f5f5e3)
- May 28, 2002: Reissued, Historical. [certificate](https://openairdocs.org/files/sha256/f6/2c/f62c54212ab6ddb96d10a79ca8ae1aec65858cb27dcdaa4019553449c282437c)

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