An analysis of the work schedules of Great Barrier Reef pilots

SECTION 1 - BACKGROUND

A recent survey of the lifestyle behaviours and industry specific factors associated with the health, stress and fatigue of Australian seafarers identified several areas which may impinge upon the health and potential for fatigue in Great Barrier Reef pilots. An important finding was the poor quality and duration of sleep experienced by pilots at sea which has been shown in other populations to be associated with mood and performance decrements and increased fatigue. While fatigue has clearly been identified as a major factor in accident risk in other transport industries it has only recently been shown that fatigue may be a contributing factor to a significantly greater number of marine accidents than previously reported (McCallum et al. 1996). The nature and demands of marine pilotage in the Great Barrier Reef and the environmental sensitivity of this region was the catalyst for the commissioning by AMSA of an investigation into the work practices of Great Barrier Reef pilots and the likely impact of these work practices on the fatigue of pilots. The project was undertaken by a research team coordinated by the Queensland University of Technology, and involved the following phases:

• Phase I  A review of the existing literature of the work practices of marine pilots
• Phase II  Analysis of work schedule data across an 18 month period (1 Jan 1996 - 30 June 1997) to develop a description of ship and non-ship time.
• Phase III  A background survey of pilots designed to provide a profile of this group and an overall description of sleep patterns, pilotage specific experience and alertness.
• Phase IV  A background survey of wives/partners of marine pilots to identify the impact of pilotage work on home and family life and address psychosocial issues.
• Phase V  The use of on-tour logs to provide specific information about ship time (bridge and sleep periods) and non-ship time ashore (sleep periods). This information will be used to help validate work schedule data and provide information on the relationship between work/rest patterns and alertness.

The information resulting from these investigations will be valuable in the development of strategies and guidelines to reduce the potential for fatigue and risk of accident.

This interim report represents Phase II of the project and contains analyses of retrospective work schedule data provided by AMSA. A Pilot Advisory Group, group comprising one member from each of the pilotage companies operating in the Great Barrier Reef – Torres Strait region was associated with all stages of the projects development. Regular meetings were held with the researchers and a representative from AMSA and there were frequent informal communications between members of the Advisory Group and the research team.

SECTION 2 - INTRODUCTION

The Great Barrier Reef – Torres Strait region has been recognised both nationally and internationally as a unique and environmentally sensitive area. It has been registered on the World Heritage List and in 1990, was identified by the International Maritime Organisation as the world’s first, and to date only, ‘Particularly Sensitive Sea Area’ (Queensland Department of Transport & AMSA 1996). Coastal pilotage in the region is centred on the movement of ships along and through the Great Barrier Reef, with pilotage times ranging from 10 hours to in excess of 60 hours. Pilotage is often conducted in trying conditions with pilots having to cope with varying ship, equipment and crew standards combined with the vagaries of weather and traffic. Additionally, ships may be carrying potentially hazardous and highly polluting cargo, and are often deep laden causing intricate navigational problems. Hence, it is possible that the characteristics of Great Barrier Reef pilotage may have the potential to impact on fatigue levels and work performance.

There are three pilotage companies operating in the Great Barrier Reef region. Each company allocates work based on a turn system designed to ensure equality between pilots in workload, rest breaks and income, and to match pilot abilities with expected work requirements. Work schedules involve tours of duty during which time pilots are on call and perform one or more work assignments. Time between work assignments is spent ashore recuperating, and if necessary travelling to the next port location. For pilots who live in close proximity to their work location, recovery time between assignments may be spent at home. However, a considerable number of Great Barrier Reef pilots live distant from their work and hence time between work assignments is spent in alternative accommodation (e.g., hotels, motels, pilot houses). Following a tour of duty an extended period of rest at home is usually taken.

Marine pilotage work is dependent on shipping demands and tidal conditions and as a consequence, work schedules are highly irregular. Work may be undertaken at any time of the day or night, as is evidenced by an investigation of United Kingdom pilots revealing that the entire 24 hour period was represented when the starting and finishing times of marine pilotage work patterns were analysed (Shipley & Cook, 1980). Night work is common, with preliminary findings from the present investigation indicating that 54 percent of ship time of Great Barrier Reef pilots is undertaken during the night (where night is defined as between 1818 and 0525 hours) (Parker et al. unpublished observations).

Work during unconventional hours opposes the normal diurnal nature of the human body, as individuals attempt to maintain high levels of alertness when their body is anticipating sleep, and try to sleep when alertness and arousal are naturally increasing. As a consequence, sleep quantity and quality are frequently compromised and circadian dissociation may be experienced. This, in turn, leads to increased levels of fatigue, mood deterioration and performance decrements (Akerstedt 1995; Condon et al. 1988; Krueger 1989; Monk 1989; Monk & Folkard 1992; Rosekind et al. 1996; Scott & Ladou 1990; TSB 1997). Specifically, performance on cognitive, vigilance and memory tasks may be adversely affected by fatigue (Griffiths 1993; Krueger 1989; TSB 1997). In terms of pilotage performance, this may result in lowered levels of vigilance, slowed reaction times, impaired decision making and judgment and adopting simpler, but riskier problem solving strategies (Couper 1996; Dinges 1992; Sanquist et al. 1996).

Additionally, it has been recognised that working during unconventional hours may be associated with a greater relative risk of accidents. Findings from primary studies (Hopkins 1992; Summala & Mikkola 1994) and a number of review articles (Brown 1994; Couper 1996; Folkard 1997; Mitler et al. 1988; Sanquist et al. 1996) indicate that accident risk is greatest during the early morning hours, particularly 0300 hours, with an additional but smaller peak in accident risk occurring in the mid- afternoon. This characteristic pattern has been attributed to underlying circadian rhythms and suggests working during the circadian trough in alertness is associated with an increased risk of accident (Brown 1994; Couper 1996; Folkard 1997; Mitler et al. 1988; Sanquitst et al. 1996; Summala & Mikkola 1994).

While in the past, only a small proportion of marine incidents were thought to be fatigue related, more recent information has suggested otherwise. For example, the US Coast Guard Research and Development Centre identified that 16 percent of critical vessel casualties and 33 percent of personnel injury casualties in US Coastal waters between 1 July and 31 December 1995, had some fatigue contribution (McCallum et al. 1996). These figures were more than 10 times greater than the estimates established from data collected in 1993 (1.2 percent and 1.3 percent for vessel casualties and personnel injuries respectively) (McCallum et al. 1996).

There is continuing research activity designed to develop a greater understanding of the relationship between sleep, fatigue and transportation accidents. This research has identified a number of work conditions which significantly contribute to fatigue-related incidents. Some of the conditions include the number of consecutive days work prior to an incident, the number of days worked in the 30 days prior to an incident, hours on duty prior to the incident and hours worked in the past 24, 48 or 72 hours (McCallum et al. 1996). Additionally, duration of the last sleep period, total number of hours slept during the 24 hours prior to an incident and whether or not a split sleeping schedule had been adopted are important predictors of fatigue-related accidents (National Transportation Safety Board 1995).

Of particular concern to regulatory bodies such as the Australian Maritime Safety Authority is the potential impact the work characteristics of Great Barrier Reef pilots may exert on fatigue. This retrospective analysis of the work schedules of Great Barrier Reef pilots will provide a basic description of the work patterns of Great Barrier Reef pilots in terms of ship and non-ship time. Additionally, the analysis will identify the presence and extent of potential fatigue indicators, such as duration of work and rest and the placement of these within the 24 hour cycle.

SECTION 3 - METHODS

3.1 Aims

The aims of the retrospective analysis of the work schedules were to: (i) develop a basic description of the work patterns of Great Barrier Reef pilots based on ship and non-ship times, (ii) incorporate and assess the impact of work-related travel time into the description of the work patterns; (iii) identify aspects from the work schedules which may be related to fatigue while working on the bridge; and (iv) identify factors which may enhance the present work schedule reporting

3.2 Measures

The primary measures included: (i) the number of tours of duty, (ii) number of work assignments, (iii) breaks between tours of duty, (iv) breaks between work assignments; and (v) night time hours. Definitions of the key measures are shown in Table 3.0.

Table 3.0 Definition of key measures

Further details of the calculation of primary measures are shown in Appendix A.

The work schedule files contained data on all work assignments performed across the 18 month period from January 1 1996 to June 30 1997 by Great Barrier Reef pilots. Information in the work schedules relevant to the study included company code, date, time and location of embarkation and disembarkation, shipping route travelled and type of vessel piloted. The work schedule files, which are compiled by the pilotage companies from invoices submitted by pilots on the completion of work assignments, were supplied to the researchers by the Australian Maritime Safety Authority, with full cooperation from the companies.

All measures were based on the sample sizes shown in Tables 3.1, 3.2 and 3.3. In total, data from 4310 work assignments completed during 902 tours of duty by 64 pilots was available.

Table 3.1 Number of pilots, tours of duty and work assignments for Company A for each 6 month period.

Table 3.2 Number of pilots, tours of duty and work assignments for Company B for each 6 month period.

Table 3.3 Number of pilots, tours of duty and work assignments for Company C for each 6 month period **.

Note:

• Period 1 = 1.01.96-30.06.96
• Period 2 = 1.07.96-31.12.96
• Period 3 = 1.01.97-30.06.97

* The time period corresponding to the period in which the work assignment or tour began.

** Company C’s operations began in the first time period and take place in one region (Hydrographers Passage). In Period 1, two pilots in Company C each did one tour comprising only one work assignment. 838 tours of duty were used to calculate breaks between tours. 64 tours and work assignments were not used in break calculation as the break duration was not available for the first tour or work assignment.

3.3 Travel

Great Barrier Reef pilots engage in substantial amounts of work-related travel and hence, one of the aims of the study was to assess the impact of travel on work patterns. Accordingly, the work schedule files were adjusted to incorporate data on travel. The three types of travel data input into the work schedule file were: (I) travel to and from tours of duty; (ii) travel to and from embarkation and disembarkation grounds (boarding grounds located off shore); and (iii) travel between work assignments. In consultation with Great Barrier Reef pilot advisory group members, only travel to and from ships and between work assignments was considered to constitute work. The duration of the travel to and from tours of duty and between work assignments was determined from standard airline schedules, while travel times to and from embarkation and disembarkation were provided by the pilotage companies. All travel times were confirmed by Pilot Advisory Group members. Waiting times at airports and boarding grounds were not included in the analysis and thus, the estimates of travel times were likely to be conservative.

3.4 Data analysis

The data analysis assessed differences between companies and shipping routes, as well as across the 18 month analysis period. To assess changes across time, the 18 month period was divided into three 6 month periods. The results have been presented as means and standard errors, with analysis of variance (ANOVA) being used to determine between company and time period differences. When significant differences were present, post hoc testing was used to determine the source of the differences. Additionally, frequency distributions of the key measures have been used to show the amount of variability within the data set and to identify extreme deviations from mean values.

In the tables giving the results of the ANOVA models, means (and standard errors of the mean) are presented. These were based on the fitted ANOVA model so that, for example, the reported company means have been adjusted for any differences in the way the workloads of the companies were spread over the three time periods. On some occasions however, the adjusted means were not able to be estimated. In these cases the unadjusted company means ignoring the time periods have been reported. In most cases there was little difference between such adjusted and unadjusted means.

The effect of incorporating travel time into the calculation of the key measures was assessed using either paired t-test or non parametric comparisons of frequency distributions. In all but one case, the incorporation of travel made a highly significant difference which was operationally important. For example, there were significant travel effects on the duration of assignments, duration of breaks between assignments and the proportion of the work assignment performed at night. Travel time has therefore been incorporated into key measures.

In order to exercise some control over the number of spuriously significant results arising from the large number of statistical tests undertaken, while at the same time minimising the risk of ignoring potentially important differences, only p-values less than 0.01 are considered statistically significant in this report.

The differences in operations between the three pilotage companies servicing the Great Barrier Reef -Torres Strait region, make inter-company comparisons of the present results somewhat difficult. Company C operate only on Hydrographers Passage and therefore have distinctly different work patterns as compared to Companies A and B, both of which operate throughout the entire Great Barrier Reef -Torres Strait region. As a consequence, inter-company comparisons mostly involve the two companies with similar operational procedures (i.e. Companies A and B). Wherever possible comparisons with relevant published findings are shown.

3.5 Presentation of Results

The results are presented in four sections: (i) tours of duty; (ii) work assignments; (iii) shipping routes; and (iv) a description of travel. The schematic diagram below presents the key measures in each of these sections.

Figure 3.0 Schematic diagram of key measures from the retrospective work schedules

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