Assessment of risk from human performance on the flight deck - Driving sound design decisions

As part of continued airworthiness processes encompassed in a safety management system, the airplane manufacturer is required to monitor in-service events to ensure that events compromising the ability of safe continued flight and landing with catastrophic outcome occur with a likelihood of below 10^-9 events per flight hour/cycle. The reliability of system components can typically be obtained based on failure statistics. A reliable statement on the flight crew performance however, in situations which require flight crew intervention, is harder to make. To support rigorous evaluation of crew performance a Boeing team has developed a tool named CREW - Cockpit-operations Reliability Evaluation Worksheet. CREW collects all factors impacting flight crew performance and supports a decision on whether changes to interface and procedure design or training are required as well as pointing at potential solutions. This paper is discussing the considerations leading to the development of CREW as well as providing some insight into the tool´s application in the in service safety process.