Risk Awareness and Decision Making in Shipping

Copyright © IFAC Transportation Systems Chania, Greece, 1997

RISK AWARENESS AND DECISION MAKING IN SHlPPING

dr. J.A. Stoop

Delft University of Technology Faculty ofSystems Engineering, Policy Analysis and Management

Abstract: Risk is a multidimensional notion in any industrial sector and society depends on the actors involved, social-economical factors, complexity and nature of the technology and the safety culture of the environment in which its operates. Risk, as an aspect in decison making in operator tasks, is also multidimensional. Accident analysis in various fleet segments in the maritime industry demonstrate that a specific approach to risk decision making is required to fully understand the nature of the decisions and risk perception of the operators. In additon to the traditional frequentistic approach, the use of a scenario approach could improve the identification of typical events, taking into the culture and context in which they occur. Such an approach could lay the basis for adaptive automation and knowledge based training of operators to improve their problem solving capacity and to enhance their risk decision making processes. Keywords: adaptive control, decision making, risk, safety, ship control

I.

RISK DECISION IN TIffiORY

In psychological literature a wide variety in rational decision making theories and techniques is available, depending on the nature of the risk, the risk perception of the actors and the context of the decision making process. Individual risk acceptance is assumed to be dependent on the perception of the risk, balanced against the perceived benefits. Assessing risky activities to risk standards is characterized as a 'satisfycing' approach, which can be applied rapidly and satisfactory if measurable standards are practically available. Although such an approach may satisfy the needs of management and policy making, it is argued that it will not satisfy the needs in a broader discussion about public acceptability of risks (Schaalsma, Vlek en Lourens 1990, Van Ravenzwaaij 1994). A 'maximizing' approach takes into account the balancing of anticipated risks, costs and benefits of an activity compared with an ahernative activity. A 'maximizing' decision maker: therefore is prepared to accept a higher risk level if the benefits are higher and costs are lower. Rational decision theories which deal with such an optimazation of a decision problem require a broader and more detailed analysis of the decision making alternatives, their probabilities and relative consequences of all posible effects. A comparative decision analysis rather deals with the optimazation of a set of variables -among which risk aspects- than with the acceptability of risk as such.

However, not every type of decision making problem requires a 'satisfycing' or 'maximizing' approach. Decision making problems can be defined on three levels of complexity. On an operational level simple 'production rule' types of a 'if-then' nature will satisfy and require cognitive capabilities on the 'skill based' and 'rule based' level as defined by Reason and Rasmussen. On a tactical level the application of quantified risk standards and current procedures will satisfy the needs of a decision maker in his regular operational practice. Risk decision making problems on a strategic level are complex, have a qualitative nature and are comprehensive in their effects. Such decision making problems require an encompassing analysis, containing all possible options, and a thourough insight into their costs and benefits. At this strategic level a sequential decision process exists and the results of these decisions will generally determine the achievable risk levels on lower orders of decision making. At the strategic level economical and logistical aspects tend to dominate, while at the tactical and operational level focus on a safe and efficient performance of the tasks. In psychologicalliteratme a distinction is made in the nature of decision making information. Depending on their role and interests, a difference is observed among decision makers whether they rely on frequentistic information or scenario information for balancing their risk options (Hendrickx 1991 ). A frequentistic perception of risk emphasizes the

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probability of an event and relies on statistical information on accident occurrence and dominant societal perception on the acceptability of risks in terms of individual or group risk standards. Frequentistic risk perceptions may overestimate the manageability of events and induce overreliance among operators in the systems performance. Strong but wrong assumptions about the actual risk and their mitigation strategies may hamper an adequate performance. A scenario perception of risk emphasizes the likelyhood of a chain of events and stresses the possible outcomes in terms of damage and injuries. A scenario perception of risks requires a detailed knowledge of the system to enable descriptions of the events, their possible outcomes and manageability of the sequences (Hendrickx 1991).

In the definition of risk, institutional aspects in various levels of decision making play an inportant role. In general three levels of decision making play a role for the operator in the execution of his tasks (Stoop 1995). On a micro level the operator is involved in a solitary task maintaining horizontal and vertical navigation in his man-machine environment. On a meso level he is involved in an interactive task performance with other fairway users, for which he has to acquire an image of the traffic situation and has to communicate with other individuals on the bridge as well as on shore. The man on the bridge has to 'negotiate' his way through the traffic, exchanging information with other fairway users, pilots on board of his vessel, shore based decision support systems and traffic management authorities. On a macro level he is involved in strategic decision making, balancing safety against other performance parameters dealing with the exploitation of the vessel, such as costs, punctuality, loading capacity and preparation of the journey. Between the various levels a vivid interaction may take place. His autonomous decision making capability and situation awareness are eroded by such traffic management influences, especially in confined waters with marginal manoevring capabilities, dense traffic or aggravating conditions. In such situations he is restricted to a supervisory task. However, in critical conditions, a captain is assumed to take his responsibilities in order to avoid damage and casualties conform his legal obligations of 'good seamanship' and should respond immediately and adequately to the oncoming event. 2.

OPERATIONAL PRACTICE

In order to analyse the decision making process of operators in the maritime industry, valuable use can be made of accident investigation reports and verdicts of maritime courts. Such reports and verdicts are

often the only source of detailed information available. They contain detailed descriptions of the accident sequence, supply explanations of the behaviour of the operator in control, his decision environment and take additional contributing factors into account (Stoop 1993). By their nature, such courts are composed of maritime experts with professional and operational experience. Since such courts have the policy to investigate accidents for the benefit of learning and preventioo, accidents are selected which have the potential of gaining detailed insight in current operational practice. Such reports and verdicts however have their limitations. In most courts, the possibility to take disciplinary action against an operator is not excluded from the investigation process. Accidents may be selected as an example for learning pmposes, but may not be representing operational practice in general. These limitations have to be compensated by additional research into systems characteristics, task analysis or simulatim techniques (Stoop 1990). Conclusions based on singular events have to be supported by additional statistical analysis of larger accident data banks (Stoop, hengst and Dirkse 1996). Patterns recognition techniques enable selection of relevant accident types. fleet segments or sailing areas (Stoop 1995). Throughout a number of maritime research projects the verdicts of the Dutch Maritime Court provided the basis for analysing the decision making of operators in a wide variety of maritime sectors. Analyses focussed on the fishing industry, Dutch merchant vessels sailing the european waters in Scandinavia, the North. Sea. Westerscheld estuary and Port of Rotterdam area and shortsea vessels on inland waters. From these analyses a number of generic observations emerged: although the maritime industry in general has a high risk awareness, the risk perception differed between sectors. fleet segments and sailing areas. These differences seem to depend on the Me of integration of risk in the cultural and social attitude of the various comnl1mities. While on one band, high risk levels are accepted in the fishing comDllmity, risk perception and mitigation is the dominant issue in the transportation of hazardous materials and the sailing of shortsea vessels on inland waters the processes underlying the decision making differs considerably per sector. In each sector specific economic cost-benefit considerations of a strategic nature may indirectly affect the safety in operational decisions such as the costs of pilotage in \Dlfamiliar or restricted waters, crew size, the use of flags of convenience, . .loading capacity in shallow waters or fishing

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segment due to the very high risk management standards, crew qualification and vessels certification. Risk perception and risk management in this segemnt is closely related to the risk culture in the chemical and process industry.

mder aggravated weather conditions the various levels of task performance require a distinction between risk perception and acceptance. Risk taking behaviour on an operational level has never been observed because no professional seaman will deliberately endanger his vessel or crew. On a tactical level a low risk perception may occur as a consequence of routine task performance. However, due to lack of vigilance or arousal an operator may find himself caught in a 1DlaDticipated situation for which he has no adeqaute response. At a strategic level risk is frequently accepted, balancing against other operational aspects such as catch prospects, loading capacity or shortcut in routes to save fuel and travel time. On this level dealing with the risk is considered a cost-benefit optimazation challenge to the professional skills of the captain or operator. 3.

SPECIFIC OBSERVAnONS

;pecific issues were clarified during the analysis wich were only relevant for the fleet segment and ;ailing areas in which they occurred. In contrast to a ;tatjstical analysis which only indicates a general mage and isolated accident causation factors, ;pecific patterns became apparant containing :haracteristic accident types and circumstances. ;pecific issues were identified: in the fishing industry the primary task is to catch fish in a maritime environment. Fishing activities may interfere with sailing activities and pose a risk on the crew and vessel, especially mder aggravating weather conditions foreign merchant vessels in Dutch coastal waters frequently sail in mfimliliar waters. Such voyages may induce risk Que to the rel~pe tp requesf fer pilotage IQld due tp crew commmication problems with pilots and shore based support although shortsea vessels sailing in inland waters are equipped with highly qualified crew and vessels, this segment sails lUlder marginal conditions with respect to draught limitations, keel clearance and marginal manoeuvring capabilities Dutch merchant vessels up to 1600 brt infrequently visit Scandinavian waters in which they are relatively lUlfiuniliar. Due to minimal crew situations and routine journey preparations, they may f1Dl into high risk situations due to aggravated conditions, inaccurate navigation or lack of pilotage the transportation of hazardous materials is perceived as a high risk category, but but hardly any accident or incident has occurred with this

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A limited problem solving capability on a tactical and operational level was demonstrated by vessels operating under critical conditions. On one hand operators on these vessels lacked cognitive skills. In a number of cases they did not have adequate alternatives at their disposal to cope with the situation due to insufficient training, operational experience or familiarization with the specific fairway situation. On the other hand the vessel was operated in the margins of its safe operating envelope. Fairway geometry, vessel width, keel clearance, dynamic vessel characteristics such as speed, rudder deflection or propellor efficiency put limits on the operations of any vessel, leaving no margin if the vessel is operated near these limits. If a deviation occurs, insufficient recovery time and space is available before an accident takes place. The operational performance of a vessel may be subjected to the consequences of strategic decisions which forces the operator to perform his tasks in the margins of the safe operating envelope. For shortsea vessels sailing in inland waters, the preparation of a journey is an important part of the voyage. During loading the shallowness of the fairway has to be taken into account in detail in advance because the draught of the vessel and the shallowness have to be matched very accurately. A maximum draught benefits the cost-effectiveness of the voyage because the payload is directly related to the cargo fare and water level. Such a detailed knowledge of the fairway is considered a challenge to the skills of the captain, ship-owner and pilot. Untill some years ago fisherman stayed at sea as much as possible to maximize their catch. Especially under aggravated conditions serious accidents occurred in which lives and vessels were lost. With the introduction of individual maximum allowable catch quota and consequently the limitations in allowed fishing days, catch capacity resource management became necessary. As a consequence, the fisherman stay in the harbour during poor weather conditions, based on catch cost-benefit considerations. Consequently, the number of serious accidents has decreased drastically because a risk taking behaviour is no longer profitable. The complexity of a task may interfere with a normative performance, even mder normal operating conditions. Situation awareness and mode awareness occurred in situations where high demands were put

system parameters should be on-line identified and if necessary, reconfigured to survive critical conditions (Mulder 1997). Such an approach seems to be profitable in maintaining safety margins in high density traffic flows. Concurrent with such adaptive control, the training of operators should be transformed 'from drill to skill' (Froese 1996). Training skills in simulators should be focussing on knowledge, scenario typing of events and increased problem solving capacity. Such automation should not be generic, but should take into account the specific requirements and the safety culture of that segment of operators. Combining adaptive automation, on-line identification and reconfigmation and training knowledge may well define challenges for future research in the incorporation of risk awareness in decision making of operators.

on inexperienced bridge crew members, most of them young mates. Fairway familiarity, bridge and equipment layout, complexity of the traffic situation in the sailing area caused a mental overload in specific situations. Accidents due to task complexity occurred in situations where the transfer of information and communication lacked. Inappropriate transfer of vital data during the changing of the watch, inadequate communication between captain, helsman and pilot or communication between vessel and shore based support systems caused inadequate position or mode awareness and consequently lead to accidents and strandings. Finally, task interference was observed on a number of fleet segments which have their primary task in other areas. Frequently accidents occur with vessels which are fishing, towing or dredging in or near shipping lanes, port areas and confined and dense traffic areas. Focussing on their primary tasks, these operators become entrapped in this task and may ignore signals from their equipment and perceptional triggers which are essential for a safe navigation (Stoop 1990). Such task interferences have their roots in goal interferences. On a strategic level economic goals are dominant with respect to catching fish, dredging or towing a vessel in a most cost-efficient way. However, these strategic goals have to be fulfilled in a maritime environment, among dense traffic or aggravated circumstances, geopardizing the cost-effectiveness of the task on an operational level. Unless the risks and possible disastrous effects are clearly perceived, such as in the transport of hazardous materials, the low probability, familiarity with the risks and routine operations may lead to an acceptance of the effects and a decreased risk awarenesss. 4.

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AMBIGUOUS EFFECTS OF AUTOMAnON

Delft University Analytics..

Automation of operators tasks traditionally has been argued from a standpoint of workload reduction and performance improvement. Major improvements have been achieved by automation and safety levels have increased significally (Glansdorp et.al. 1994). However, evidence is building up that the workload has not been reduced, but shifted from physical to cognitive. Situation and systems mode awareness have been decreased (Endsley 1995). This decreased awareness has lead to typical accidents such as 'controlled flight into terrain' in aviation and 'Arpaassisted collisions' in shipping. Taking into account the complexity and multilevel nature of decision ' making, evidence is build up that the presentation of information to operators should be structured in terms of 'adaptive automation' by keeping the operator in the control loop (Endsley 1995). In a dynamic approach it is recommended that the man-machine

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