Understanding and Managing Threats

Introduction to Threat and Error Management

Threat and Error Management (TEM) is a framework developed to enhance aviation safety by addressing threats and errors systematically, preventing them from escalating into undesired aircraft states. Understanding this framework is crucial for pilots as it equips them to manage and mitigate potential risks effectively.

Definition of ‘Threat’ in Aviation

In the context of aviation, a threat is defined as any event or error beyond the control of the flight crew or Air Traffic Control Officer (ATCO) that increases operational complexity. These occurrences require active management to maintain safety margins and prevent the progression to undesired aircraft states. Threats can vary widely, impacting various aspects of flight operations.

Examples of Threats

Flight Deck Threats

Weather Conditions: Adverse weather phenomena, such as thunderstorms or icing conditions.
Maintenance Errors: Errors occurring during aircraft maintenance that impact flight safety.
Human Errors: Mistakes made by ground crew, cabin crew, or passengers.
Air Traffic Control (ATC) Errors: Miscommunications with ATC, similar call signs, or incompatible airspace restrictions.
Infrastructure Challenges: Unfamiliar terrain or airports, system malfunctions, and noise restrictions.
Operational Pressures: Time pressures, heavy traffic, flight diversions, and missed approaches.
Automation and Flight Systems: Issues related to automated flight systems or system malfunctions.

ATC Threats

Communication and System Failures: Failures in systems or communication impacting operations.
Operational Demands: Land and Hold Short Operations (LAHSO), Simultaneous Intersecting Runway Operations (SIRO).
Environmental Conditions: Weather considerations, runway inspections, and heavy traffic.
Regulatory Challenges: Reduced separation minima, noise restrictions, airspace reclassification.

Sources: Threat and Error Management, Line Operations Safety - ICAO

Development of Undesired Aircraft States

An undesired aircraft state (UAS) arises when errors or mismanaged threats result in deviations from the intended flight path, aircraft position, or speed that reduce safety margins. Understanding how UAS develop is key to preventing them. Here are examples illustrating this development:

From Unmanaged Threats

Example 1: Encountering unexpected severe turbulence without managing airspeed can lead to structural stress or passenger injury, resulting in an unsafe state.
Example 2: Failure to anticipate a possible runway incursion due to similar taxiway signs or call signs can result in conflicts with other aircraft, leading to a hazardous situation.

From Errors

Procedural Errors: Failing to properly execute a missed approach procedure can result in unsafe altitudes or headings.
Aircraft Handling Errors: Inadequate wind correction during approach could lead to runway excursion.
Communication Errors: Misinterpretation of landing clearance can result in runway incursions or go-arounds.

Management Strategies

To address threats and errors effectively, aviation relies on both systemic and personal countermeasures:

Systemic-Based Countermeasures

Tools and Procedures: Use of technologies like ACAS (Airborne Collision Avoidance System) and GPWS (Ground Proximity Warning System), adherence to Standard Operating Procedures (SOPs), and comprehensive training.

Personal Strategies

Crew Resource Management (CRM): A critical component is CRM, which involves planning, execution, and post-flight review to enhance team synergy and decision-making.

Through proactive management and adherence to established procedures, the flight crew plays a pivotal role in maintaining safety and minimizing the risks of threats evolving into errors or undesired aircraft states.

Sources: Threat and Error Management (TEM) in Flight Operations - SKYbrary