# STC SA521EA-D

- Type: Supplemental type certificate
- Status: Current, Amended
- Holder: American Airlines Inc, United States
- Description: Install a single area navigation system
- Applied: May 1, 1968
- Status date: December 5, 1969
- Product: Aircraft, Large Airplane
- Certification basis: Part 21
- Data sheets: [TCDS A3WE](https://openairdocs.org/tcds/A3WE)
- Certificate PDF: https://openairdocs.org/files/sha256/6f/5e/6f5ee8b100a3d8f09566675e4abb7d5a291bc4073a6f74b9b13718d1d20da8a6
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/B7FAC5053801C50E86257E75004D78DA.0001
- DRS record last changed: December 5, 2025
- Page: https://openairdocs.org/stc/SA521EA-D

## ADs that name it (0)

None.

## Approved models (1)

- The Boeing Company 727-200 Series ([TCDS A3WE](https://openairdocs.org/tcds/A3WE))

## What the certificate says

This is OCR from the scanned FAA certificate. OCR can misread letters and numbers.

United States of America Department of Transportation Federal Aviation Administration Supplemental Type Certificate Number: SA521BA-D This certificate issued to: American Airlines, Inc.

Maintenance and Engineering Center Tulsa, Oklahoma 74151 Part 4b of the CIVIL Air Regulations.

Original Product - Type bestificate Numben: ABSTE Make: Boeing Model: 727-223 Description of Type Design Change:

Install a single area navigation system manufactured by Butler-National Corp.

Mission, Kansas per American Airlines ECO H.01401A dated 5-1-68.

II. Install production model of area navigation system installed in Item I per American Airlines ECO H.01715C dated 11-25-69 and ECO H.01734A dated 11-30-69.

III. Install a single vertical navigation system manufactured by Butler-National Corp.

Mission, Kansas per American Airlines ECO H.01715C dated 11-25-69 and ECO H.01734A dated 11-30-69.

See Attached Page

Date of Application: May 1, 1968 Date Reissued:

Date of Issuance: June 7, 1968 Date Amended: December 5, 1969

VIATION ' Signature, Coordinator DASLEA (Title)

47.

SIC SA52IEA-D Amended: 12/5/69 * December 5, 1969 Pag… 2 Limitations and Conditions: This approval should not be incorporated in any aircraft of this specific model on which other approved modifications are incorporated, unless it is determined that the interrelationship between this change and any of those previously incorporated approved modifications will not introduce any adverse effects upon the airworthiness of the aircraft. The vertical navigation system (Item III) has been approved as supplemental equipment only, and no flight opèrations may be predicated on its use.

following FAA/DAS approved Flight Manual Supplement is required with this installation. 727-223 American Airlines Supplementary Revision AAL-4 dated 12-5-69 to the FAA approved AFM, Boeing Document No. D6-8728.3.

TRANSFER ENDORSEMENT 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) Exent of Authority (if licensing agreement) :

Signature of grantor (In ink) :

Page 2 01 2

## Every issue (1)

- December 5, 1969: Amended, Current. [certificate](https://openairdocs.org/files/sha256/6f/5e/6f5ee8b100a3d8f09566675e4abb7d5a291bc4073a6f74b9b13718d1d20da8a6)

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