# AC 20-115A: Radio Technical Commission for Aeronautics Document RTCA/DO-178A

- Type: Advisory circular (guidance, not mandatory unless a rule or AD requires it)
- Status: Historical
- Version in force: [AC 20-115D](https://openairdocs.org/ac/20-115), approved July 21, 2017. This is a historical version
- Approved: August 12, 1986
- Last reviewed: August 26, 2019
- Family: AC 20-115
- Cancels: [AC 20-115](https://openairdocs.org/ac/20-115)
- Cancelled by: [AC 20-115B](https://openairdocs.org/ac/20-115B)
- 14 CFR parts: 21, 23, 25, 27, 29, 33
- Pages: 1
- PDF: https://openairdocs.org/files/sha256/21/4e/214ee4f0aa3c33e2b338155f1e89230269ace80b494e93ac2fa2f1f6e3d686d7
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/2D8369776D5B0B1486258462005322D6.0001
- DRS record last changed: November 22, 2025
- Page: https://openairdocs.org/ac/20-115A

## Versions

- [AC 20-115D](https://openairdocs.org/ac/20-115) (Current), approved Jul 21, 2017, 15 pages
- [AC 20-115C](https://openairdocs.org/ac/20-115C) (Historical), approved Jul 19, 2013, 13 pages
- [AC 20-115B](https://openairdocs.org/ac/20-115B) (Historical), approved Jan 11, 1993, 1 page
- [AC 20-115A](https://openairdocs.org/ac/20-115A) (Historical), approved Aug 12, 1986, 1 page
- [AC 20-115](https://openairdocs.org/ac/20-115?v=66A4949C7A8405CC862584620051EE73) (Historical), approved Sep 3, 1982, 1 page

## ADs that cite it (1)

- [AD 2020-24-02](https://openairdocs.org/ad/2020-24-02): Auto flight, Flight controls, and Indicating/recording systems · Boeing 737-8 and 737-9. Effective Nov 20, 2020

## Text

Each page's text from the PDF; open the PDF at a page with #page=N. This is OCR from the scanned FAA advisory circular. OCR can misread letters and numbers.

### Page 1 (OCR)

10A TECHICAL UNT AdViSOrY U.S. Department DOT LIBRARY MASS CircUlar MAY 8 1987 or Transportation Federal Aviation Administration Subject: Radio Technical Cammission for Date: 8/12/86 AC No:20-115A Aeronautics Document RICA/DO-178A Initiated by: AWS-120 Change:

1. PURPOSE. This advisory circular calls attention to the Radio Technical Commission for Aeronautics (RICA) Document RICA/DO-178A, 'Software Considerations in Airborne Systems and Equipment Certification," issued March 1985. It discusses how the document may be applied with Federal Aviation Administration technical standard order (50), type certification MC), and supplemental type certification (SIC) authorizations.

CANCELLATION. Advisory Circular 20-115, Radio Technical Commission for Aeronautics (RICA) Document DO-178, dated September 3, 1982, is cancelled.

3. RELATED FEDERAL AVIATION REGULATIONS (FAR). FAR Parts 21, 23, 25, 27, 29, and 33.

BACKGROUND. RICA Document RICA/DO-178A was developed to establish software considerations for developers, installers, and users when the aircraft equipment design is implemented using microcomputer techniques.

It is expected that current and future avionics designs will make extensive use of this technology. The RICA document outlines verification, validation, documentation, and software configuration management and quality assurance disciplines to be used in microcomputer systems.

5. USE OF RICA/DO-178A PROCEDURES. An applicant for a 150, IC or SIC authorization for any electronic equipment or system employing digital computer technology may use the considerations outlined in RICA Document RICA/DO-178A as a means, but not the only means, to secure FAA approval of the digital computer software. The FAA may publish advisory circulars for specific FAR's, outlining the relationship between the criticality of the software-based systems and the appropriate "software level" as defined in RICA/DO-178A. Those may differ from and will take precedence over the application of RICA/DO-178A.

6. AVAILABILITY OF RICA DOCUMENT RICA/DO-178A. Copies may be purchased from the Radio Technical Commission for Aeronautics Secretariat, One McPherson Square, 1425 K Street NW., Suite 500, Washington, DC 20005.

Willion t allor.

William J. Sullivan Deputy Director of Airworthiness

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