Unsafe System Operating Conditions – Preventing a Bad Day from Becoming a Really Bad Day

The safety of commercial aviation industry has come under extensive scrutiny and how the system safety process is applied. One specific system safety regulation concerns how unsafe system operating conditions are meeting regulatory requirements. Minimal regulatory guidance was available on this topic and an industry committee (American Society for Testing of Materials) decided to provide a consensus standard with input from a cross-section of airplane manufacturers, suppliers, and regulatory authorities on what is meant by an unsafe system operating condition and how compliance can be shown to the regulation(s). The committee determined that an unsafe system operating condition is when a failure condition severity increases (to hazardous or catastrophic) due to crewmember(s) inaction. For example, if a hazard has occurred it is possible the severity can increase to an unacceptable level as the crewmember(s) are not aware of the hazard. Enabling the crewmember(s) to mitigate the failure condition is an extremely effective method to support continued safe flight and landing of the airplane. Once a failure condition has been identified as an unsafe system operating condition, safeguards must be utilized to mitigate a more severe failure condition from occurring. These safeguards may include: additional warning devices, aural alerts, inherent detection of the crewmember(s), and airplane flight manual procedures. One key aspect was to take credit for normal airmanship of the crewmembers. Taking credit for basic crewmember airmanship has been accepted in the past and it is extremely important to continue this concept again. Crewmembers are thoroughly trained and contain a unique skillset and not expecting them to apply basic airmanship is unrealistic while encountering a failure condition or hazard. The final step after identifying unsafe system operating conditions is to document this process and use it as part of the certification process. This process will enable that a consistent process is applied to all airplanes and ultimately result in a safer commercial aviation industry.