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Description / Abstract:
This document discusses the development of aircraft systems
taking into account the overall aircraft operating environment and
functions. This includes validation of requirements and
verification of the design implementation for certification and
product assurance. It provides practices for showing compliance
with the regulations and serves to assist a company in developing
and meeting its own internal standards by considering the
guidelines herein.
The guidelines in this document were developed in the context of
Title 14 Code of Federal Regulations (14CFR) Part 25 and European
Aviation Safety Agency (EASA) Certification Specification (CS)
CS-25. It may be applicable to other regulations, such as Parts 23,
27, 29, 33, and 35 (CS-23, CS-27, CS-29, CS-E, CS-P).
This document addresses the development cycle for aircraft and
systems that implement aircraft functions. It does not include
specific coverage of detailed software or electronic hardware
development, safety assessment processes, inservice safety
activities, aircraft structural development nor does it address the
development of the Master Minimum Equipment List (MMEL) or
Configuration Deviation List (CDL). More detailed coverage of the
software aspects of development are found in RTCA document DO-178B,
"Software Considerations in Airborne Systems and Equipment
Certification" and its EUROCAE counterpart, ED-12B. Coverage of
electronic hardware aspects of development are found in RTCA
document DO-254/EUROCAE ED-80, "Design Assurance Guidance for
Airborne Electronic Hardware". Design guidance and certification
considerations for integrated modular avionics are found in
appropriate RTCA/EUROCAE document DO-297/ED-124. Methodologies for
safety assessment processes are outlined in SAE document ARP4761,
"Guidelines and Methods for Conducting the Safety Assessment
Process on Civil Airborne Systems and Equipment". Details for
in-service safety assessment are found in ARP5150, "Safety
Assessment of Transport Airplanes In Commercial Service" and
ARP5151 Safety Assessment of General Aviation Airplanes and
Rotorcraft In Commercial Service." Post-certification activities
(modification to a certificated product) are covered in section 6
of this document. The regulations and processes used to develop and
approve the MMEL vary throughout the world. Guidance for the
development of the MMEL should be sought from the local
airworthiness authority.
The relationships between the various development documents,
which provide guidelines for safety assessment, electronic hardware
and software life-cycle processes and the system development
process described herein.
Purpose
The guidelines herein are directed toward systems that support
aircraft-level functions and have failure modes with the potential
to affect the safety of the aircraft. Typically, these systems
involve significant interactions with other systems in a larger
integrated environment. Frequently, significant elements of these
systems are developed by separate individuals, groups or
organizations. These systems require added design discipline and
development structure to ensure that safety and operational
requirements can be fully realized and substantiated. A top down
iterative approach from aircraft level downwards is key to
initiating the processes outlined herein.
The contents are recommended practices and should not be
construed to be regulatory requirements. For this reason, the use
of words such as "shall" and "must" is avoided except if used in
the context of an example. It is recognized that alternative
methods to the processes described or referenced in this document
may be available to an organization desiring to obtain
certification.
This document provides neither guidelines concerning the
structure of an individual organization nor how the
responsibilities for certification activities are divided. No such
guidance should be inferred from the descriptions provided.