Threat and error management

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Threat and error management model

Threat and error management (TEM) is an overarching safety management approach that assumes that pilots will naturally make mistakes and encounter risky situations during flight operations. Rather than try to avoid these threats and errors, its primary focus is on teaching pilots to manage these issues so they do not impair safety. Its goal is to maintain safety margins by training pilots and flight crews to detect and respond to events that are likely to cause damage (threats) as well as mistakes that are most likely to be made (errors) during flight operations. [1]

Aircrew personnel operating an aircraft in flight, including pilots, systems operators, and attendants

Aircrew, also called flight crew, are personnel who operate an aircraft while in flight. The composition of a flight's crew depends on the type of aircraft, plus the flight's duration and purpose.


TEM allows crews to measure the complexities of a specific organization's context meaning that the threats and errors encountered by pilots will vary depending upon the type of flight operation and record human performance in that context. [2] TEM also considers technical (e.g. mechanical) and environmental issues, and incorporates strategies from Crew Resource Management to teach pilots to manage threats and errors.

The TEM framework was developed in 1994 by psychologists at University of Texas based on the investigation of accidents of high capacity Regular Public Transport (RPT) airlines. [3] However, an evaluation method was needed to identify threats and errors during flight operations and to add information to existing TEM data. [4] [5] A Line Operations Safety Audit (LOSA) serves this purpose and involves the identification and collection of safety-related information on crew performance, environmental conditions, and operational complexity by a highly trained observer. [5] [6] LOSA data is used to assess the effectiveness of an organization's training program and to find out how trained procedures are being implemented in day-to-day flights.

Air operators certificate approval by national aviation authorities to operate aircraft for commercial purposes

An air operator's certificate (AOC) is the approval granted by a national aviation authority (NAA) to an aircraft operator to allow it to use aircraft for commercial purposes. This requires the operator to have personnel, assets and system in place to ensure the safety of its employees and the general public. The certificate will list the aircraft types and registrations to be used, for what purpose and in what area – specific airports or geographic region.

Importance of TEM

Threat and error management is an important element in the training of competent pilots that can effectively manage in-flight challenges. [1] Many strategies have been developed (e.g. training, teamwork, reallocating workload) that were focused on improving on stress, fatigue, and error. Flight crew training stressed the importance of operational procedures and technical knowledge, with less emphasis placed on nontechnical skills, which became isolated from the real-world operational contexts. [4] Safety training, including TEM, is important because a crew's nontechnical (safety) knowledge helps more in managing errors effectively than crews' familiarization with operations through experience. [7] Candidates who are shortlisted during selection and training processes must demonstrate analytical and coordination capabilities. [8] Possessing these nontechnical skills allows pilots and crew members to carry out their duties efficiently and effectively.

Pilot error decision, action or inaction by a pilot of an aircraft

Historically, the term pilot error has been used to describe an accident in which an action or decision made by the pilot was the cause or a contributing factor that led to the accident, but also includes the pilot’s failure to make a correct decision or take proper action. Errors are intentional actions that that fail to achieve their intended outcomes. Chicago Convention defines accident as "An occurrence associated with the operation of an aircraft [...] in which [...] a person is fatally or seriously injured [...] except when the injuries are [...] inflicted by other persons." Hence the definition of the "pilot error" does not include deliberate crash.

Components of TEM

The following components are methods that help provide data for the TEM.

LOSA observation training

Training for LOSA experts includes two sessions: education in procedural protocols, and TEM concepts and classifications. [9] A LOSA trainee is taught to find data first and then code them later for both sessions, during which a crew member must exhibit "LOSA Etiquette" ability to notify the pilot as to why he or she was not able to detect an error or threat after a flight. The pilot's responsibilities include his or her opinions on what safety issues could have had an adverse impact on their operations. A LOSA trainee must then record the specific responses of the pilot and thereafter code performance using behavioral markers. The order of the recording is as follows: a) record visible threats; b) identify error types, crew's responses, and specific outcomes; and c) use CRM behavioral markers to rate crew. [10]

Crew resource management or cockpit resource management (CRM) is a set of training procedures for use in environments where human error can have devastating effects. Used primarily for improving aviation safety, CRM focuses on interpersonal communication, leadership, and decision making in the cockpit of an airliner. Its pioneer was David Beaty, a former Royal Air Force pilot and later a BOAC pilot who wrote his seminal book The Human Factor in Aircraft Accidents in the late 1950s. Despite the considerable development of electronic aids since then, many of principles he developed continue to prove effective today.

Observers will finally record a pilot's overall response on a 4-point Likert scale: 1) poor, 2) marginal, 3) good, and 4) outstanding. The data are then quantified and tabulated as exemplified by the following format: [9]

Likert scale psychometric measurement scale

A Likert scale is a psychometric scale commonly involved in research that employs questionnaires. It is the most widely used approach to scaling responses in survey research, such that the term is often used interchangeably with rating scale, although there are other types of rating scales.

Planning and execution of performance

TaskTask DescriptionCommentsRating
Monitor cross-checkActive monitoring of crewsSituational awareness maintainedOutstanding
SOP briefingCarried out necessary briefingsThorough understanding of procedures
Contingency ManagementCommunicate strategiesGood management of threats and errors.
Identified ThreatsManagedMismanaged*Frequency (N)
Air Traffic Control17219
Airline Operational Pressure909

Frequency is the total number of threats that occurred and is denoted by N.

Categories of the LOSA

LOSA identifies three main categories that must be recorded:

Safety change process

Safety change process (SCP), which is part of LOSA, is a formal mechanism that airlines can use to identify active and latent threats to flight operations. [15] It is a guideline that communicates in detail what is an imminent threat to current operations or who is causing the threat. In the past, SCP data were based on investigation of accidents or incidents, experiences, and intuitions but nowadays SCP focuses more on the precursors to accidents. [15] There are several steps involved in conducting SCP: [15]

An unnamed airline conducted base-line observations from 1996 to 1998 using the defined SCP and LOSA data to improve its organization's safety culture and the results were positive. The crew error-trapping rate was significantly increased to 55%, meaning that crews were able to detect about 55% of the errors they caused. [15] A 40% reduction in errors related to checklist performance and a 62% reduction in unstabilized approaches (tailstrikes, controlled flight into terrain, runway excursions, etc.) were observed. [15] A proper review and management of SCP and LOSA data can prevent further disasters in flight operations.

See also

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