AC 20-115

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The Advisory Circular AC 20-115( ), Airborne Software Development Assurance Using EUROCAE ED-12( ) and RTCA DO-178( ) (previously Airborne Software Assurance), recognizes^[1] 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.^[2]^[3] 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.^[4]

AbbreviationAC 20-115

Year started1982

Latest versionD
2017

OrganizationFederal Aviation Administration

Quick facts Airborne Software Development Assurance Using EUROCAE ED-12( ) and RTCA DO-178( ), Abbreviation ...

Airborne Software Development Assurance Using EUROCAE ED-12( ) and RTCA DO-178( )
FAA Publication
Abbreviation	AC 20-115
Year started	1982
Latest version	D 2017 (2017)
Organization	Federal Aviation Administration
Predecessor	C
Domain	Aviation safety
Website	FAA

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.^[5]

Harmonized Software EASA AMC 20-115D

Simultaneously with the publication of FAA AC 20-115D, EASA issued AMC 20-115D. This EASA Acceptable Means of Compliance (AMC) publication resulted from 2 years of coordinate effort with the FAA on AMC 20-115D to improve harmonization and mutual recognition between the civil aviation authorities. AMC 20-115D and AC 20-115D are technically identical.^[6] However, there are some wording differences.

More information EASA AMC 20-115D, FAA AC 20-115D ...

Comparison of Statements Regarding Acceptable and Alternate Means of Compliance
EASA AMC 20-115D	FAA AC 20-115D
Compliance with this AMC is not mandatory and therefore an applicant may elect to use an alternative means of compliance (AltMoC).	This AC is not mandatory and does not constitute a regulation.
However, the AltMoC must meet the relevant requirements, ensure an equivalent level of software safety as this AMC, and be approved by the European Aviation Safety Agency (EASA) on a product or ETSO article basis.	However, if you use the means described in the AC, you must follow it in all applicable respects.

Revision History

More information Revision, Year ...

History of AC 20-115
Revision	Year	Summary
AC 20-115	1982	Called attention to RTCA DO-178.^[7]
AC 20-115A	1986	Called attention to RTCA DO-178A.^[7]^[8]
AC 20-115B	1993	Called attention to RTCA DO-178B.^[9]
AC 20-115C	2013	Calls attention to RTCA DO-178C^[3] w/guidance for Rev B to Rev C change.^[10]
AC 20-115D	2017	Minor updates largely to harmonize with EASA guidance.^[11]^[4]^[12] Additional Guidance for Field Loadable Software and for User Modifiable Software.

References

[1]
Leanna Rierson (19 December 2017) [7 January 2013]. Developing Safety-Critical Software: A Practical Guide for Aviation Software and DO-178C Compliance. CRC Press. p. 49. ISBN 9781351834056. Retrieved 2024-04-10. The recognition typically comes in the form of an Advisory Circular (AC) for the FAA and equivalent advisory materials by other certification authorities.
[2]
Cary Spitzer; Uma Ferrell; Thomas Ferrell, eds. (2015). Digital Avionics Handbook, Avionics, Development and Implementation (3rd ed.). Boca Raton, FL: CRC Press. p. 12-2. ISBN 978-1138076983. 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].
[3]
Cary Spitzer; Uma Ferrell; Thomas Ferrell, eds. (2015). Digital Avionics Handbook, Avionics, Development and Implementation (3rd ed.). Boca Raton, FL: CRC Press. pp. 13–9. ISBN 978-1138076983. The FAA formally recognized DO-178C, DO-330, and the three technical supplements via Advisory Circular (AC) 20-115C in July 2013.
[4]
"Harmonised Software EASA AMC and FAA AC 20-115D have been published!". www.easa.europa.eu. 24 Oct 2017. Retrieved 2022-07-01. It paves the way towards more harmonisation and mutual recognition of each other's activities in the domain of Software aspects of certification.
[5]
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."
[6]
"Harmonised Software EASA AMC and FAA AC 20-115D have been published!". EASA. 2017. Retrieved 2026-02-23.
[7]
"Advisory Circulars" (PDF). Aviation Impact Reform. Retrieved March 28, 2018. – List of ACs made from the Special Collections of the United States Department of Transportation Library (AC's from 1982 / AC's from 1986)
[8]
Malvern J. Atherton (2005). System Theoretic Framework for Assuring Safety and Dependability of Highly Integrated Aero Engine Control Systems (PDF) (Master of Science thesis). Massachusetts Institute of Technology. p. 16. Retrieved 24 Jan 2016. 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.
[9]
AC 20-115B, FAA, 1993.
[10]
AC 20-115C, FAA, 2013.
[11]
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."
[12]
S.L. Fuller (October 24, 2017). "EASA Publishes Means of Compliance Materials for Software Alongside FAA". Aviation Today. Retrieved 2022-07-01. 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.

AC 20-115

Harmonized Software EASA AMC 20-115D

Revision History

References

External links

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