Aerospace systems are becoming more and more complex due to customer requirements for greater capability versus unit cost. Increased dependence on software controlled systems, and a desire to maximize the use of commercial off the shelf (COTS) items, exponentially adds to the already complex task of ensuring that new systems are safe.
Sikorsky is required to meet widely varying demands for aircraft system safety for both civil and military customer requirements with little coordination between authorities where system safety analysis methodology is concerned.
Military and civil authorities each require different types of analyses provided at different stages of the development process. Even the definitions of hazard severity differ among regulatory agencies and customers. To address the differences between industry standards and better learn from the data collected Sikorsky endeavored to create a unified approach to system safety in aircraft development programs.
In trying to develop a unified process, Sikorsky conducted an extensive search of literature on similar efforts as well as a search to identify existing software that either met the requirements or could be easily modified to accommodate them. These searches resulted in neither literature that adequately addressed the entire development process or the accommodation of civil and military specific requirements, nor did it produce any comprehensive software solutions as the currently available safety specific software is focused on component reliability, environmental health and safety, and/or post accident root cause analysis.
As no comprehensive solution existed, Sikorsky, already familiar with ASTs platform capabilities, partnered with AST to develop and implement the Linear Integrated Safety Analyses (LISA) application to address all of the elements of a modern system safety process and standardize safety assessments for aircraft development programs.
LISA will provide end-to-end coverage and traceability for requirements and verification, as well as defined integration with engineering groups that are not part of the core safety process.
This paper, Presented at the 31st International System Safety Conference, Boston, Massachusetts, August 12-16, 2013, describes the Linear Integrated Safety Analyses (LISA) process developed by the Sikorsky Aircraft Corporation (Sikorsky). The LISA architecture is designed to encompass all aspects of safety risk management for aircraft development programs. It is linear in that each assessment is repeated at the aircraft, system and subsystem levels in sequence and it is integrated such that all analyses are connected and fully traceable to requirements.