AC 20-115

{{Infobox technology standard

| title = Airborne Software Development Assurance Using EUROCAE {{nowrap|ED-12( )}} and RTCA {{nowrap|DO-178( )}}

| image = US-FederalAviationAdmin-Seal.svg

| caption = FAA Publication

| status =

| year_started = 1982

| version = D

| predecessor = C

| versionDate = {{Start date|df=yes|2017}}

| organization = Federal Aviation Administration

| abbreviation = AC 20-115

| domain = Aviation safety

| website = [https://www.faa.gov/regulations_policies/advisory_circulars/index.cfm/go/document.information/documentID/1032046 FAA]

}}

The Advisory Circular AC 20-115( ), Airborne Software Development Assurance Using EUROCAE {{nowrap|ED-12( )}} and RTCA {{nowrap|DO-178( )}} (previously Airborne Software Assurance), recognizes{{cite book|url= https://books.google.com/books?id=nAlEDwAAQBAJ |title= Developing Safety-Critical Software: A Practical Guide for Aviation Software and DO-178C Compliance |author= Leanna Rierson |isbn= 9781351834056 |orig-date= 7 January 2013 |date= 19 December 2017 |access-date= 2024-04-10 |publisher= CRC Press |page= 49 |quote= The recognition typically comes in the form of an Advisory Circular (AC) for the FAA and equivalent advisory materials by other certification authorities. }} the RTCA published standard DO-178 as defining a suitable means for demonstrating compliance with applicable airworthiness regulations for the use of software within aircraft systems.{{cite book |editor=Cary Spitzer |editor2=Uma Ferrell |editor3=Thomas Ferrell |title= Digital Avionics Handbook, Avionics, Development and Implementation |edition= 3rd |publisher= CRC Press |location= Boca Raton, FL |year= 2015 |page= 12-2 |isbn=978-1138076983 |quote= Advisory circular (AC) 20-115B specifies DO-178B as an acceptable means, but not the only means, for receiving regulatory approval for software in systems or equipment being certified under a [TSO, TC or STC]. }} The present revision D of the circular identifies ED-12/DO-178 Revision C as the active revision of that standard and particularly acknowledges the synchronization of ED-12 and DO-178 at that revision.

This Advisory Circular calls attention to ED-12C/DO-178C as "an acceptable means, but not the only means," to secure FAA approval of software. The earliest revisions of the Advisory Circular were brief, serving little more than to call attention to active DO-178 revisions. The Advisory Circular revisions C and D are considerably longer, giving guidance in modifying and re-using software previously approved using DO-178, DO-178A, or DO-178B (preceding revisions of the DO-178 standard). Additionally, the expanded AC now provides guidance for Field Loadable Software and User Modifiable Software within aircraft software. Transition of legacy tool qualification from DO-178B to DO-330 is also discussed, with comparison of ED-12B/DO-178B Tool Qualification Type with ED-12C/ED-215 DO-178C/DO-330 Tool Qualification Level.[https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_20-115C.pdf AC 20-115C], FAA, 2013. "This AC also establishes guidance for transitioning to DO-178C when making modifications to software previously approved using DO-178, DO-178A, or DO-178B."

Revision History

class="wikitable" style="text-align:left;"

|+ History of AC 20-115

! Revision !! Year !! Summary

AC 20-115

| 1982

| Called attention to RTCA DO-178.{{cite web| title = Advisory Circulars |website= Aviation Impact Reform | url = http://aireform.com/wp-content/uploads/20161217cpy..-ACs-from-1957-2000-copied-from-DoT-Special-Collection-webpage-71p.pdf | access-date = March 28, 2018}} – List of ACs made from the [https://dotlibrary.specialcollection.net Special Collections] of the United States Department of Transportation Library (AC's from 1982 / AC's from 1986)

style="white-space: nowrap;"|AC 20-115A

| 1986

| Called attention to RTCA DO-178A.{{cite thesis |degree=Master of Science | author = Malvern J. Atherton | title = System Theoretic Framework for Assuring Safety and Dependability of Highly Integrated Aero Engine Control Systems | url = http://dspace.mit.edu/bitstream/handle/1721.1/32477/61772088-mit.pdf?sequence=2 |page=16 | quote = It refers to AC 20-115A (superseded by B), which itself identifies DO-178B as defining a suitable means for demonstrating compliance for the use of software within aircraft systems. | year = 2005 | publisher = Massachusetts Institute of Technology | access-date = 24 Jan 2016 }}

style="white-space: nowrap;"|AC 20-115B

| 1993

| Called attention to RTCA DO-178B.[http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/list/AC%2020-115B/$FILE/AC20-115B.pdf AC 20-115B], FAA, 1993.

style="white-space: nowrap;"|AC 20-115C

| 2013

| Calls attention to RTCA DO-178C{{cite book |editor=Cary Spitzer |editor2=Uma Ferrell |editor3=Thomas Ferrell |title= Digital Avionics Handbook, Avionics, Development and Implementation |edition= 3rd |publisher= CRC Press |location= Boca Raton, FL |year= 2015 |pages= 13–9 |isbn=978-1138076983 |quote= The FAA formally recognized DO-178C, DO-330, and the three technical supplements via Advisory Circular (AC) 20-115C in July 2013. }} w/guidance for Rev B to Rev C change.[https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_20-115C.pdf AC 20-115C], FAA, 2013.

style="white-space: nowrap;"|AC 20-115D

|2017

|Minor updates largely to harmonize with EASA guidance.[https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_20-115D.pdf AC 20-115D], FAA, Office AIR-134, 2017. "The technical content of this AC is as far as practicable harmonized with European Union Aviation Safety Agency (EASA) AMC 20-115D, equally based on ED-12C/DO-178C."{{cite web |title= Harmonised Software EASA AMC and FAA AC 20-115D have been published! |website= www.easa.europa.eu |date= 24 Oct 2017 |access-date= 2022-07-01 |url= https://www.easa.europa.eu/newsroom-and-events/news/harmonised-software-easa-amc-and-faa-ac-20-115d-have-been-published |quote= It paves the way towards more harmonisation and mutual recognition of each other’s activities in the domain of Software aspects of certification. }}{{cite journal |author= S.L. Fuller |date= October 24, 2017 |journal= Aviation Today |title= EASA Publishes Means of Compliance Materials for Software Alongside FAA |access-date= 2022-07-01 |url= https://www.aviationtoday.com/2017/10/24/easa-publishes-means-compliance-materials-alongside-faa/ |quote= This publication is a result of two years of work with the FAA and U.S. and European industry associations, EASA said. ... It has been issued simultaneously with FAA AC 20-115D, which EASA said is technically identical. }}
Additional Guidance for Field Loadable Software and for User Modifiable Software.

== References ==

{{reflist}}

== External links ==

  • [https://www.faa.gov/regulations_policies/advisory_circulars/index.cfm/go/document.information/documentID/1032046 AC 20-115D, Airborne Software Assurance]

Category:Avionics

Category:Safety

Category:Software requirements

Category:RTCA standards

Category:Computer standards

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