# STC SA1231SW

- Type: Supplemental type certificate
- Status: Current, Reissued
- Holder: Century Flight Systems Inc, United States
- Description: Installation of Mitchell automatic flight system Model AK311 consisting of Century II and IIB autopilot with optional radio coupler.
- Applied: November 9, 1970
- Status date: July 9, 1984
- Product: Aircraft, Single-Engine
- Certification basis: Part 21
- Data sheets: [TCDS 3A15](https://openairdocs.org/tcds/3A15)
- Certificate PDF: https://openairdocs.org/files/sha256/98/fd/98fddbb95268df1f915a7143e7d20a40279c3e676c2c0bb82cd32a902692c26a
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/D558AA53A5B17A7985256CC10080E070.0001
- DRS record last changed: December 5, 2025
- Page: https://openairdocs.org/stc/SA1231SW

## ADs that name it (0)

None.

## Approved models (13)

- Beechcraft Corporation 35-A33 ([TCDS 3A15](https://openairdocs.org/tcds/3A15))
- Beechcraft Corporation 35-B33 ([TCDS 3A15](https://openairdocs.org/tcds/3A15))
- Beechcraft Corporation 35-C33 ([TCDS 3A15](https://openairdocs.org/tcds/3A15))
- Beechcraft Corporation 35-C33A ([TCDS 3A15](https://openairdocs.org/tcds/3A15))
- Beechcraft Corporation 36 ([TCDS 3A15](https://openairdocs.org/tcds/3A15))
- Beechcraft Corporation A36 ([TCDS 3A15](https://openairdocs.org/tcds/3A15))
- Beechcraft Corporation E33 ([TCDS 3A15](https://openairdocs.org/tcds/3A15))
- Beechcraft Corporation E33A ([TCDS 3A15](https://openairdocs.org/tcds/3A15))
- Beechcraft Corporation E33C ([TCDS 3A15](https://openairdocs.org/tcds/3A15))
- Beechcraft Corporation F33 ([TCDS 3A15](https://openairdocs.org/tcds/3A15))
- Beechcraft Corporation F33A ([TCDS 3A15](https://openairdocs.org/tcds/3A15))
- Beechcraft Corporation F33C ([TCDS 3A15](https://openairdocs.org/tcds/3A15))
- Beechcraft Corporation G33 ([TCDS 3A15](https://openairdocs.org/tcds/3A15))

## 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.

©Epartmtnt of "Cransportation -federal atoiation administration Supplemental 'Cuje Certificate tyKivmver- SA1231SW Century Flight Systems, Inc.

F.M. 1195 P. 0. Box 610 Mineral Wells, TX 76067 ',^Jiwetuf£M*'M^^ *aa Civil Air fa fbtavnad <%neUic/ —— , fySi* ~fy*rpfytfade-:'/iti'm/ief- • 3 A 1 5 Beech 35-A33, 35-B33, 35-C33, 35-C33A, E33, E33A E33C, F33, F33A, F33C, G33, 36 and A36 ^'XAftrMi&cvts tif-Jyfit Jr.'^Atavi ~faAa,rio4. :

Installation of Mitchell Automatic Flight System Model AK311 consisting of Century II and Century IIB Autopilot with Optional Radio Coupler according to Bulletin No. 419, Revision 4, dated 5/13/74 and Master Drawing List No. 87A605 , Revision A, dated 2/27/73. Installation of Mitchell Radio Coupler Model 1C388-3 according to Bulletin No. 611, Revision 1, dated 4/16/74 and Master Drawing List No. 87A708, Revision A, dated 4/16/74. . . .

See Continuation Sheet, Page 2, a part of this STC.

' •S%e6rr>*f : November 9, 1970 ' December 8, 1970 L/<,& P^iously approved modif ications 7-12-72; 2-28-73; 4-16-74;

7-9-84, Revision 4 Don P. Watson ($>g™«>«) Manager, Aircraft Certification Division Southwest Region Any alteration of thu certificate w punishable by a fine of not exceeding tl ,000, or imprisonment not exceeding 3 years, or bath.

Tfin ftitifeale may be Iranifer'td in accordance with I-AR 21 -17.

[NS I RUC F IQNiJ: The transfer rndo?'•emem In1 low may In- u*,e<! *t> nuliK tin- appropriate FA A I'c-^ional Offirr ihc iransfrr of ihis SitpplriiK-nuil Typ' {.Irnificatr I In- I-A A "'ill rtn issue ihc crriifn att m the namr- {>t thr transferee and forward it Lo him.

TRANSFER ENDORSEMENT Transfer the ownership of Supplemental Type Certificate Number ___._ Co (Name of trans/eree) (Address of transferee) fumbfi and ilrfftj (City, Stale, and £IP aJi) from (Naint of grantor) (Print or type) (Address oj grantor) r and street} ity, Stab, and $P code/ Extent of Authority (if licensing agreement):

Signature of grantor (In ink):

Untai gtatu flf antrtca

•Bcpartmtnt of Craasportation— JFtdcral atriation administration Supplemental Tgpc Certificate(Continuation £heet) SA1231SW, Revision A dated 7-9-84 Limitations and Conditions:

The following FAA Approved Placards are required:

1. Placard 13A344-311 for Century II installation in Beech Models 36 and A36.

2. Placard 13A689-311 for Century IIB installation in Beech Models 36 and A36.

3. Placard 13A689-311-1 for Century IIB installation in Beech Models F33A, S/N CE-316 and Up, E33A, F33C, 35-C33A, E33C, and G33.

4. Placard 13A689-311-2 for Century IIB installation in Beech Models F33A, S/N CE-315 and below, 35-A33, 35-B33, 35-C33, E33, and F33.

5. FAA Approved Autopilot Flight Manual Supplement P/N 68S168 is required for installation of Mitchell Radio Coupler Model 1C388-3.

FAA FORM BIIO-I-I (i*-W) This ttrtificaU may bt tnmsftrrid in attendant! with FAR 21.47.

**PAQE 2 OF 2 PAGES**

## Every issue (1)

- July 9, 1984: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/98/fd/98fddbb95268df1f915a7143e7d20a40279c3e676c2c0bb82cd32a902692c26a)

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From OpenAirDocs.org, an independent open copy of FAA and NTSB data. Only the Federal Register edition on govinfo.gov is the official legal text of an AD.