# STC SA3-404

- Type: Supplemental type certificate
- Status: Current, Reissued
- Holder: Sabreliner Aviation LLC, United States
- Description: Installation of Sperry SP20 autopilot.
- Applied: June 8, 1959
- Status date: March 7, 2014
- Product: Aircraft, Large Multi-Engine
- Certification basis: Part 21
- Data sheets: [TCDS 1A7](https://openairdocs.org/tcds/1A7)
- Certificate PDF: https://openairdocs.org/files/sha256/ea/fb/eafb0563acc6483e91eb60f4642070f3bf05421ce141a1aac6472555b46f3d30
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/18CDDB070F38EB6986257D6D006C8A95.0001
- DRS record last changed: December 5, 2025
- Page: https://openairdocs.org/stc/SA3-404

## ADs that name it (0)

None.

## Approved models (1)

- Martin-Marietta Corporation 404 ([TCDS 1A7](https://openairdocs.org/tcds/1A7))

## 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.

Sabreliner Aviation, LLC.

1390 Highway H Perryville, MO 63775 4b Civil Air .

- 1A7 Martin 404

Installation of Sperry SP20 autopilot. Data Required:

1. Remmert-Werner Drawing No's. 404-01000 through 404-01010, or later FAA approved revision.

2. Remmert-Werner Airplane Flight Manual Supplement dated July 31, 1959, to basic TWA Martin 404 Airplane Flight Manual, or later FAA approved revision.

Servo Stall Forces measured at Pilot's Control are:

Rudder: 40# min. – 45# max.

Elevator: 30# min. – 32# max.

Aileron: 8# min. – 10# max.

This approval should not be extended to other aircraft 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 aircraft.

October 1, 1970; March 25, 1981; June 30, 1983 March 7, 2014

(Signature) Grant E. Youngdahl Program Manager Wichita Aircraft Certification Office (Title)

June 8, 1959

June 15, 1959

FAA FORM 8110-2-1(10-69) PAGE 2 of 2 PAGES

Transfer the ownership of Supplemental Type Certificate Number

to (Name of transferee)

(Address of transferee) (Number and street)

(City, State, and Zip code)

from (Name of grantor) (Print or type)

(Address of grantor) (Number and street)

(City, State, and Zip code)

Signature of grantor (in ink):

## Every issue (1)

- March 7, 2014: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/ea/fb/eafb0563acc6483e91eb60f4642070f3bf05421ce141a1aac6472555b46f3d30)

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