Line Operations Safety Audit (LOSA)

Line Operations Safety Audit (LOSA)


Line Operations Safety Audit (LOSA) is seen as an important way to help develop countermeasures to operational errors. It involves a structured programme of observation of front line activities built around the Threat and Error Management (TEM) concept. It aims to identify threats to operational safety, identify and minimise the risks which are the origin of such threats and implement measures to manage the human error aspects of the residual risk. LOSA provides a way to assess the level of organisational resilience to systemic threats in accordance with the principles of a data-driven approach.

LOSA uses trained observers to collect data about pilot behaviour and its situational context on “normal” flights from supernumerary seats on the flight deck. Such monitoring allows the capture of data which can characterise pilot strategies for managing "threats, errors and undesirable states". The audits are conducted under strict no-jeopardy conditions; therefore, flight crews are not held accountable for their actions and errors that are observed. During flights that are being audited, observers record and code:

  • potential threats to safety;
  • how the threats are addressed;
  • the errors such threats generate;
  • how flight crews manage these errors;
  • specific behaviours that have been known to be associated with accidents and incidents.

The LOSA method is seen as closely linked with Crew Resource Management (CRM) training. A particular strength of LOSA is perceived as the way it identifies examples of "superior" pilot performance that can be provide models for use in training.


The initial research and project definition was a joint endeavour between The University of Texas at Austin and Continental Airlines, with funding provided by the Federal Aviation Administration (FAA). In 1999, International Civil Aviation Organisation (ICAO) endorsed LOSA as the primary tool to develop countermeasures to human error in aviation operations and made LOSA the central focus of its Flight Safety and Human Factors Programme for the period 2000 to 2004. The number of operators joining LOSA grew in the period following March 2001 to include some major international operators from different parts of the world and diverse cultures but a reliable picture of the extent of continued use is not known.

Role of ICAO

ICAO has promoted the potential of LOSA and acted as an enabling partner in the LOSA programme. ICAO has developed a manual (Doc 9803) that provides an introduction to the concept, methodology and tools of LOSA and to the potential remedial actions which can be undertaken using the data collected.

Related Articles

Further Reading



Regulatory References


SKYbrary Partners:

Safety knowledge contributed by: