The Threat and Error Management (TEM) model is a conceptual framework that assists in understanding, from an operational perspective, the inter-relationship between safety and human performance in dynamic and challenging operational contexts. It is based on three components, threats, errors and undersired aircraft states.

Threats are the first line of defense, and are times or places where a potential error could be made qute easily. They can be classed as latent threats, environmental threats, or organisational threats, depending on how the threat has occured in the first place.

Errors are classified based upon the primary interaction of the pilot or flight crew at the moment the error is committed. Therefore they can be classed as aircraft handling errors, procedural errors or communication errors, depending on what has occured to let the error happen. These are three of the main error types.

Undesired aircraft states occur due to errors being allowed to happen and potentially putting the aircraft in a state that it should not be in, undesired attitude, location, low on fuel, etc. These are a consequence, but if the threat and following error have not been picked up by the flight crew already, then the undesired aircraft state is where the flight crew should realise that there is a problem, and take action to return to safe operations.

There are some counter-measures that can be put in place to aid Threat and Error Management, probably the largest of which is the set of systemic counter-measures that are put in place by all operators. These are parts of the system that have been created or develoed specificaly to aid TEM and safety procedure. They can be things like:

• Airborne Collision Avoidance Systems (ACAS/TCAS)
• Ground Proximity Warning Systems (GPWS)
• Standard Operation Procedures (SOPs)
• TEM training (CRM training also)
• Briefings
• Checklists