In 1994, the University of Texas Human Research Project and Delta Airline developed the Line Operations Safety Audit (LOSA) program. With time, the LOSA program evolved into what is now known as Threat and Error Management (TEM). The TEM framework is an applied concept which emerged from the observations and surveys of actual flight operations. It considers the various issues that a flight crew may encounter as a result of internal and external factors. This model explores the contributing factors of the threat to aviation safety and, in turn, allows for the unearthing of ways to mitigate them and maintain proper safety margins. Now recognized and adopted across continents, the TEM framework aims to educate flight personnel on managing threats and errors before they degenerate into serious incidents or accidents. It is important to note that TEM is also applicable to maintenance operations, cabin crew, and air traffic control.

1. Tilak Ramaprakash

2. In 1994, the University of Texas Human Research Project and
Delta Airline developed the Line Operations Safety Audit (LOSA)
program. With time, the LOSA program evolved into what is now
known as Threat and Error Management (TEM).
The TEM framework is an applied concept which emerged from
the observations and surveys of actual flight operations. It
considers the various issues that a flight crew may encounter as a
result of internal and external factors.

3. This model explores the contributing factors of the threat to
aviation safety and, in turn, allows for the unearthing of ways to
mitigate them and maintain proper safety margins. Now
recognized and adopted across continents, the TEM framework
aims to educate flight personnel on managing threats and errors
before they degenerate into serious incidents or accidents. It is
important to note that TEM is also applicable to maintenance
operations, cabin crew, and air traffic control.
Three components make up the Threat and Error Management
framework: threats, errors, and undesired aircraft state. Each
element requires proper definition as threats and errors have
subjective meanings when defined generally.

4. Threats are negative occurrences that are primarily out of the
control of the pilot or the flight crew. Nonetheless, the flight crew
must still manage these expected or unexpected adverse events
to preserve the ideal safety margin. Threats may be internal or
external.
Internal threats are fatigue, personal issues, low experience level,
boredom, and health-related problems. From the examples given,
it is easy to deduce that internal threats are individual-related.
They are the different factors that could hamper the effectiveness
of any member of the flight crew. Ideally, individual flight
personnel is expected to address them before a scheduled flight.

5. In contrast, external threats are broader and contextual. They
could be pilot-related in adverse weather conditions and
obstacles or cabin crew-related in the case of fire and disruptive
passengers. External threats could also relate to air traffic control
and maintenance-related issues. Although errors are widely
known to be unintentional, they are said to be within the control
of the flight crew.
Erring is a normal phenomenon with humans. That may not justify
it, but it should be expected in a dynamic and highly technical
work environment like the aviation sector. Errors are actions and
inactions of flight personnel that result in the digression from
operational standards, expectations, and the reduction of the
safety margin.

6. One classification of errors splits it into four categories: Slip,
lapses, mistakes, and violations. Slips are entirely unintentional as
one mistakenly does something different from what was initially
intended. In the case of lapses, they could be in the form of
memory failures or momentary inattention. Mistakes refer to
instances of poor judgment, doing something one intends to do,
which turns out to be inappropriate for the situation at hand.
Mistakes could be due to inexperience or limited knowledge.

7. However, when flight personnel deliberately deviates from the set
rules and instructions or procedures provided, it is a violation.
Examples of errors include; aircraft mishandling, scheduling
errors, incorrect calculations, and speed deviations.
Undesired aircraft state is the last stage when all efforts to
mitigate the adverse effects of threats and errors prove futile, or
the threats and errors go undetected or misdiagnosed. At this
point, the resolution of the undesired aircraft state may either
result in recovery or an accident.