SMS Tools


LOSA – NOSS (Line Operations Safety Audit & Normal Operations Safety Survey)

LOSA is a project performed by the Human Factors of the University of Texas and the Federal Aviation Administration (FAA). The aim of the LOSA initiative was to set a baseline for flight crew performance regarding Crew Resource Management (CRM) and workload management during normal operations. This baseline is based on the Threat and Error Management (TEM) principles. It was also required to set the baseline for system performance in terms of organisation culture, standards in training, maintenance of safety standards, crew support by the operations, and ATC, and the communication- relation of flight crew with ATC, Operations, ground crew and cabin crew. Being a proactive tool, LOSA is process oriented and not event based. It supports the data driven approach towards safety management. This means that the data collected refer to the how things are done, rather than the result of actions.

Observations for a LOSA programme are conducted during routine scheduled flights. There is a trusted agreement that the pilots are not checked and their job security is not jeopardised. The decision for normal routine flights is based on the requirement to have a real environment with open factors and expanded knowledge, something that is impossible to achieve 100% in a simulator environment, which has a monitored operational context. Operational decision making (e.g. on time performance) is also very difficult to reproduce in the simulators. It is important that none of the observed flights are part of training or checking of crew.

Monitoring normal operations poses a challenge on its own, as the culture of the organisation may not allow for trust and confidence. For this reason, the communication prior to conducting the observation is extremely vital for the successful outcome of the programme. The programme must be accepted and supported by all involved departments (training, operations, maintenance etc) to be effective. It is NOT owned by safety, neither by training. It is a collaborative initiative. The safety department will act as the administrator- facilitator of the process, without blocking the inputs and fears of other departments.

The observer is required to sample all activities and communications taking place in all phases of the flights. This includes all the issues and problems encountered, as well as the way crew deals with these issues. The observations must not be limited to the problems, but mostly on the identified threats by the whole system (inside and outside of the flight). LOSA is conducted throughout the whole flight phases (from pre-flight briefing up to end of duty de-briefing) and significant observations must be accomplished regarding the distractions the crew faces, especially during high workload phases.

Eventually the LOSA will assess the effectiveness of training and the degree of applicability as is being implemented into the line operations. Special consideration is given on the Human Factors elements, including the identified stressors of the crew. Points to be monitored are the usability of the checklist, the efficiency and traps of the checklists, the efficiency of the procedures, the use and applicability of standard call-outs etc. Great attention is given on the CRM, not only in terms of communication, but also in terms of usability of the available resources. The observer will also discretely take notes of any deviation, shortcuts or walkaround by the crew, either done casually, routinely or in special circumstances.

The resulting LOSA report will assess the safety margins of line operations and set the baseline for future change. As it assesses the level or resilience to systemic threats in the front-line operations, It will include a list of identified threats to the crew, as well as how the crew reacted to these, and how (if) they have dealt with these. It is important that the observer does not assess the individual performance of the crew (or a specific pilot) but only their performance in terms of threat and error management (TEM). The report should include proposal for rationalisation and efficient allocation of resources, as well as models of extreme performance observed to be used as training examples. (the first programme to achieve the milestone of positive feedback). Eventually the training will result in defining the operational context in terms of buffer zones, time delays for error execution etc) and will redesign the procedures to allow for 2nd chances and greater safety margins. The LOSA will not provide the answers and the solutions, but only the data required to work out the changes.

In order to satisfy the continuous monitoring and continuous improvement concept, LOSA is a repetitive process in order to establish the progress and identify the results. As a collaborative process, airlines are encouraged to exchange data with other members of the programme for comparison and sharing of ideas and solutions. Attention must be given when comparing data of different cultures (social and operational), even though it is promoted in an attempt to find the ideal solution. Commitment to LOSA means commitment to act upon the results, therefore the documentation is important, but most important is the existence of a process to communicate and implement the required changes across all involved departments.

Conducting of LOSA can be tricky as there are many different types of flights, routes, fleet etc. One way to declutter data is to break operations into group. Either by fleet, or by length of flight (short/long haul), or by domestic/ international etc. It is logical to use statistical analysis, which means that not all the flights, nor all the personnel will be observed, but only a sample of each category. The observer might openly at any time the situation allows, to openly ask the crew about actions performed and engage in open discussion to bring up issues, thoughts and concerns. This can be done in casual manner or in interview style questions.

The LOSA concept requires 10 operational characteristics:

  1. Observations from the jumpseat position during normal operations
  2. Confidential data collection
  3. Voluntary crew participation
  4. Trusted and trained observers
  5. Joint management – pilots sponsorship
  6. Systematic observation instruments
  7. Secure data collection
  8. Data derived targets for enhancement
  9. Data verification tables
  10. Feedback to pilots and management


Normal Operations Safety Survey is the application of the LOSA concept in the ATC environment. However, there some major differences between the flight environment and the controller’s environment, and the context must be carefully considered. The focus of the NOSS is the communications- with emphasis given on callsign confusion, the local procedures, the weather factor, and the aerodrome equipment and infrastructure.

For NOSS the following points are debatable:

  • The number of observer(s), as one is not enough due to the rapid changes of the situations
  • The observer needs a strong background and understanding of the local procedures, whilst in LOSA a trained pilot is enough
  • The phases of the ATC environment cannot be readily identified and defined (e.g. take-off, cruise or landing as in the flight phases)
  • The areas of ATC (tower, approach, ground, centre) pose a problem as the same controller might be operating more than one frequency/ area

Confusion can exist during the time of controller change (which happens frequently in a shift)