The 2nd International Conference on Computer Application and System Modeling (2012) Civil Aircraft System Integration Research Li Haomin Wu Jianhua shanghai aircraft design and research institute, comac shanghai aircraft design and research institute, comac shanghai,China shanghai,China Abstract-This paper according as the experience of china new civil aircraft developed, introduce the concept and methods of II. SYSTEM INTEGRATION PROCESS civil aircraft systems integration. Top-down system developed process was described. The systems integration and The Systems Integration Process is a comprehensive, comprehensive approach, such as requirements analysis, iterative and recursive problem solving process, applied functional analysis & allocation, safety assessment, system sequentially top-down by integrated teams. It transforms design synthesis and verification, was detailed described. This needs and requirements into a set of system product and philosophy and methods have reference and inspiration effect process descriptions, generate information for decision for developing large complex systems. makers, and provides input for the next level of development. The process is applied sequentially, one level Keyword-sRequirements analysis, Functional at a time, adding additional detail and definition with each analysis/Allocate, System integration, Safety assessment, Design synthesis, Verification level of development. As shown by Figure 2, the process includes: inputs and outputs; requirements analysis; functional analysis and allocation; requirements loop; I. INTRODUCTION synthesis; design loop; verification; and system analysis and control[1]. Civil aircraft as a highly complex large integration systems, which characterized meet customer requirements based on ensuring safety. Based on this characteristic, the development process of civil aircraft generally use a top- down process, first determine the requirements, then the functional define, then the aircraft design, then the system design, component design and produce further, and then successive components to system integration verification, functional and requirements verification, and finally delivered to the user, shown as Figure 1. Figure 2. The system integration process • System Integration Process Inputs: Input consist primarily of the customer’s needs, objectives, requirements and project constraints. • Requirements Analysis: Requirements analysis is Figure 1. Civil aircraft develop process used to develop functional and performance requirements; The advantages of doing so is very obvious, to ensure that is, customer requirements are translated into a set of that each requirements are met and the integrity of the requirements that define what the system must do and how design, to ensure compatibility between the systems, can be well it must perform. integrated, verification and airworthiness certification • Functional Analysis/Allocation: Functions are relatively easily, and better to understand the impact of a analyzed by decomposing higherlevel functions identified single function to the aircraft. International aircraft through requirements analysis into lower-level functions. manufacturer has developed this top-down process applied The performance requirements associated with the higher to a number of new aircraft development process, and have level are allocated to lower functions. solidified to the industry standard such as "ARP SAE 4754 • Safety Assessment: The safety assessment process is guidelines to civil aircraft and systems development". used by a company to show compliance with certification requirements and in meeting its own internal safety standards. [2]. Published by Atlantis Press, Paris, France. © the authors 1364 The 2nd International Conference on Computer Application and System Modeling (2012) • Design Synthesis is the process of defining the product • Functional View: The Functional View focuses on or item in terms of the physical and software elements WHAT the system must do to produce the required which together make up and define the item. operational behavior. It includes required inputs, outputs, • Verification: For each application of the system states, and transformation rules. engineering process, the solution will be compared to the • Physical View: The Physical View focuses on HOW requirements. This part of the process is called the the system is constructed. It is key to establishing the verification loop, or more commonly, Verification. Each physical interfaces among operators and equipment, and requirement at each level of development must be verifiable. technology requirements. III. REQUIREMENTA ANALYSIS IV. FUNCTIONAL ANALYSIS AND ALLOCATION A. Type Of Requirements A. Functional Analysis And Allocation Requirements are categorized in several ways. The The purpose of functional analysis and allocation is to following are common categorizations of requirements that transform the functional, performance, interface and other relate to technical management: requirements that were identified through requirements • Customer Requirements: Statements of fact and analysis into a coherent description of system functions that assumptions that define the expectations of the system in can be used to guide the Design Synthesis activity that terms of mission objectives, environment, constraints, and follows. The designer will need to know what the system measures of effectiveness and suitability. must do, how well, and what constraints will limit design • Functional Requirements: The necessary task, action flexibility. or activity that must be accomplished. Functional (what has This top-down process of translating system level to be done) requirements identified in requirements analysis requirements into detailed functional and performance will be used as the toplevel functions for functional analysis. design criteria includes: • Performance Requirements: The extent to which a • Defining the system in functional terms, then mission or function must be executed; generally measured decomposing the top-level functions into subfunctions, in terms of quantity, quality, coverage, timeliness or • Translating higher-level performance requirements into readiness. detailed functional and performance design criteria or • Derived Requirements: Requirements that are constraints, implied or transformed from higher-level requirement. For • Identifying and defining all internal and external example, a requirement for long range or high speed may functional interfaces, result in a design requirement for low weight. • Identifying functional groupings to minimize and • Allocated Requirements: A requirement that is control interfaces (functional partitioning), established by dividing or otherwise allocating a high-level • Determining the functional characteristics of existing requirement into multiple lower-level requirements. or directed components in the system and incorporating them in the analysis and allocation, B. Requirements Analysis • Performing trade studies to determine alternative Requirements analysis involves defining customer needs functional approaches to meet requirements. and objectives in the context of planned customer use, environments, and identified aircraft characteristics to B. Functional Architecture determine requirements for aircraft functions. Prior analyses The functional architecture is a top-down decomposition are reviewed and updated, refining mission and environment of aircraft functional and performance requirements. The definitions to support aircraft definition. architecture will show not only the functions that have to be The purpose of Requirements Analysis is to: performed, but also the logical sequencing of the functions • Refine customer objectives and requirements; and performance requirements associated with the functions. • Define initial performance objectives and refine them It also includes the functional description of existing. into requirements; This is an example of functional analysis and • Identify and define constraints that limit solutions; and architecture. Functions come mainly from requirements and • Define functional and performance requirements based aircraft operation philosophy. Modern civil aircraft on customer provided measures of effectiveness. operating philosophy is the safety of passengers and cargo movement from the beginning to the end, with minimal C. Requirements Analysis Output impact to the environment, and ensure the operational The requirements that result from requirements analysis efficiency and continuing airworthiness, the aircraft must be are typically expressed from one of three perspectives or maintained. In support of flight, must provide the human views. These have been described as the Operational, interface, hydraulic energy, gas supply and power supply Functional, and Physical views. and other public resources. So the aircraft basic function is • Operational View: The Operational View addresses payload, move, provide common resource, ensure safety, how the system will serve its users. support operation and compatibility with environment, shown as Figure 3. Published by Atlantis Press, Paris, France. © the authors 1365 The 2nd International Conference on Computer Application and System Modeling (2012) V. SAFETY ASSESSMENT VII. VERIFICATION Safety assessment is a important and complex aircraft The objectives of the Verification process include using system integration work. The output of safety assessmemt established criteria to conduct verification of the physical confirm