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- Ternov, Sven, et al.
(författare)
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A method, DEB analysis, for proactive risk analysis applied to air traffic control
- 2004
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Ingår i: Safety Science. - : Elsevier BV. - 0925-7535. ; 42:7, s. 657-673
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Complex production systems as, for instance, those used in health care, in off shore industry, in nuclear power industry or in aviation suffer now and then from severe system breakdowns. Lessons learnt from these often lead to changes in the "system". A more rational approach would be to identify these "system weaknesses" before accidents happen. A new proactive method, DEB analysis, for identifying hazards in a complex system was applied to an air traffic control unit in Malmoe, Sweden. The system weaknesses (i.e. latent system failures and insufficient safety barriers), which could cause these hazards, were identified. The effectiveness of the method was assessed by comparing these "prospective" identified system weaknesses with "retrospective" identified system weaknesses in a consecutive series of loss of separation cases (n = 15), investigated by the central aviation administration. Main findings: The system weaknesses in 14 out of the 15 cases were found with the proactive method. One sub-task was missed. Discussion: The method is an effective tool in disclosing system weaknesses that can give rise to hazards. The method should be modified with increased engagement of operators. It might be applied to other complex systems as well.
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- Ternov, Sven, et al.
(författare)
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Operator-centred local error management in air traffic control
- 2004
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Ingår i: Safety Science. - : Elsevier BV. - 0925-7535. ; 42:10, s. 907-920
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: A large number of air traffic control occurrences take place without resulting in loss of separation between aircraft. Unfortunately such occurrences are seldom reported and therefore not used for disclosing system weaknesses, Such as inappropriate methods and procedures. The ATCC (Air Traffic Control Centre) Malmoe made a trial with local reporting of "learning occurrences". The trial was ATCO-(Air Traffic Controller) centred. The study objectives were to evaluate if ATCOs would start to report after a defined training and marketing effort, if they could identify system weaknesses, if concrete actions for safety improvement would be taken as a result of the trial and to what extent expert support was necessary. Method and material: The trial period was eight months. The ATCO report would be made on a simple form, available on site. These reports would then be analysed in groups and the marketing and feedback efforts would be co-ordinated by the local flight safety group. Results: 43 reports were filed and analysed during the trial period. The initial motivational training and marketing was considered adequate. During the group discussions, the ATCOs identified system weaknesses within 40 of the reports. The resulting safety improvement actions included: the ATCC unit becoming more active in contacting the pilots and airline companies, the renaming of some waypoints (due to name similarities), the implementation of safer procedures when relieving ATCOs, the training of ATCOs in cockpit flight management systems, and the initiation of a research project primarily concerned with ATCO mental overload. Expert support was required in the beginning to help ATCOs focus on the system rather than on the individual.
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- Ternov, Sven, et al.
(författare)
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System weaknesses as contributing causes of accidents in health care
- 2005
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Ingår i: International Journal for Quality in Health Care. - : Oxford University Press (OUP). - 1464-3677 .- 1353-4505. ; 17:1, s. 5-13
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. Accidents in health care, resulting in injury or death to the patient, are a matter of considerable concern. The aim of this study is to examine whether system weaknesses can contribute to these accidents, and if so, how. Design. Eight consecutive accidents reported to the Health Authority in Sweden were analysed using MTO (Man-Technique-Organization) analysis. Setting. Emergency care hospitals in Sweden. Results. All cases that involved the system supported the assumption that system weaknesses are a contributing factor to accidents. In this study two types of latent failure could be identified: process control latent failures and interactional latent failures. The time span from activation of process control latent failures to operator error was very short, and the study demonstrates the simple relationship between situational factors and operator errors. Interactional latent failures exert system influence in a more indistinct manner. Latent failures, as seen in this study, act not only by creating opportunities for operator errors but also by hindering error detection in the time window available. Safety barriers, which might have prevented the accidents, could be proposed in seven out of eight cases. Conclusion. System weaknesses seem to play an important role in accident evolution. Consequently, certain measures can be suggested in order to improve patient safety: (i) sufficient resources should be allocated for research and development at both medical schools and hospitals in order to establish competence and procedures for systematic analyses of processes; and (ii) authorities handling accident cases should have adequate competence in system analysis.
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