TEM is the process of detecting and responding to threats (such as power lines or faulty equipment) and errors (such as selecting the wrong radio frequency, or missing a checklist item), to prevent safety being compromised. Left unmanaged, these threats and errors can lead to ‘undesired aircraft states’ - the last opportunity to avoid a serious incident or accident. TEM can be considered an extension to airmanship, providing a structured way to help people maintain safety margins during everyday operations. . The obvious safety benefit of recognising and managing threats, errors and undesired states before they lead to a serious incident or accident is of course not just limited to flight crews. TEM is equally applicable and relevant to cabin crew, air traffic control (ATC) and maintenance operations.