Australian Institute of Criminology

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Chapter 10: Electricity Trust of South Australia : fatal accident at Waterfall Gully

Published in:
Wayward governance : illegality and its control in the public sector / P N Grabosky
Canberra : Australian Institute of Criminology, 1989
ISBN 0 642 14605 5
(Australian studies in law, crime and justice series); pp. 161-171


In the late 1970s it became apparent that growing demand for electricity in the eastern suburbs of Adelaide would soon exceed the capacity of the existing supply system, particularly during peak summer periods. Accordingly, planners at the Electricity Trust of South Australia (ETSA) began to investigate alternative means of augmenting power supplies.

As the cost of underground cable had recently increased significantly, the Trust's options were constrained. It was decided to construct a new section of line to connect the overhead power line running from the Linden Park sub-station into the Adelaide Hills, with another existing line running south along the hills face from Magill to Panorama.

Original plans called for the new section of 66,000 volt line to cross Waterfall Gully Road, the most scenic part of Adelaide's eastern suburbs, and only a few kilometres from ETSA headquarters. However, the state Department of Environment and Planning, whose approval was required for such a project, requested significant modifications in order to preserve the existing skyline and physical environment of the Waterfall Gully area. The path eventually chosen for the new power line lay across relatively inaccessible sloping land belonging to the state Highways Department between Waterfall Gully and Mt Osmond.

Under normal circumstances, the structures built to support the new line would have been 'Stobie poles', the functional, if somewhat hazardous and less than eye-pleasing poles of steel and concrete, which line South Australia's streets and roads.

To erect Stobie poles at the site in question, however, would require the construction of access roads and site works. The resulting degradation of the hills face would have been environmentally unacceptable.

Eventually, ETSA's design office decided on three lightweight steel towers, each twenty metres tall, comprising two legs joined by a cross-arm from which the power lines would be suspended. Each leg, consisting of three tubular steel members latticed together, would be supported by steel guywires. In addition, the bottom of each leg would consist of a base plate with a hole in it which could fit into a vertical pin protruding from a concrete foundation set in the ground. The towers would be the first of their type to be constructed in South Australia (see Figure 10.1).


Proposed 66 kV Lightweight Guyed Structure
Figure 10.1 : Proposed 66 kV Lightweight Guyed Structure

But the project was to be beset by problems. Opposition on aesthetic grounds was voiced by some residents of the affluent suburb of Beaumont, whose electricity supply, ironically, the new lines were intended to augment. Resistance by the Burnside Council necessitated postponement of construction for five months. A complaint was lodged with the state Ombudsman, and it was only after an on site inspection by the Ombudsman himself that clearance to proceed was granted.

The methods of construction however, were further constrained by environmental considerations. The initial inclination to use cranes was abandoned when it became apparent that extensive earthworks and bigger tracks would be required for equipment access.

ETSA authorities contemplated the use of a helicopter to transport pre-assembled towers to the hillside location. A helicopter with requisite lifting capacity was located in Queensland, but at a rental price of $3000 per hour, the cost of flying it to Adelaide and return was deemed prohibitive. Instead, a local firm which operated a smaller helicopter and which had experience in constructing oil derricks was retained. The limited lifting capacity of this aircraft necessitated that the tower components be flown separately to the hillside site and joined in place.

This means of erection would require the ETSA workers to climb a structure supported by ropes. The team recruited to construct the towers was selected from ETSA staff. Because of the novelty of the project, and the element of risk involved in climbing unsecured structures, all those concerned were volunteers. Ten experienced linesmen were chosen from the Holden Hill, Linden Park and Stirling Depots. A district foreman grade 2, who had been involved in the project during the planning stages, was placed in charge. He was responsible to the project officer, a field engineer, who in turn was responsible to the East Metropolitan Area Engineer.

Problems continued to plague the project. Vandals visited the construction site, removed survey pegs, and filled in footings dug for pole positions. Erection of the tower was complicated by the fact that the long leg of each tower was too heavy to be lifted in one piece. Each of the three long legs had to be split, and later joined with flanges.

Components were assembled in a car park at Mount Osmond Golf Course and on Thursday 10 September 1981 the work crew was briefed. Erection of the towers began the following morning. Each leg was flown in separately, fitted to the vertical foundation pin, and guyed temporarily with polypropylene rope. The cross arm was then flown in and attached to the tops of the legs. The first two towers were erected, but not without difficulty. In joining the two sections of each long leg, the linesmen had to ascend a structure held in position with three rope guys and two steel guys. The heaviest component was said to be only 300 lb less than the helicopter's lifting capacity (Gordon 1982, p. 3). At one point, the helicopter hovered a mere three metres above the heads of the linesmen. Because the project was without precedent in ETSA operations, a video film was made of the erection of Tower 2 (Lea, Aikin & Kutcher 1981).

Alignment of the various components was not easily achieved. One of the guys on Tower 2 was incorrectly positioned. Fitting the cross-arms, suspended from the hovering helicopter, atop the legs of each tower proved more difficult than expected. The tolerance of the holes for the cross-arm pins required near perfect alignment in order for the pins to be fitted (Aiken 1981). Dags of galvanising had to be removed from the parts in order to get a satisfactory fit. Whilst it had originally been planned that one man on each tower leg would be sufficient to position the cross-arms, two men were actually needed. Because of difficulties encountered, the crossarms were initially connected to the legs with temporary 5/8 in bolts, and later replaced with permanent pins.

By Friday afternoon, the three structures were erected, but remained out of alignment. The cross-arms of each tower were still secured to the supporting legs with temporary bolts, pending readjustment. Work then ceased for the weekend, with the towers left in their temporary guyed state.

When work commenced the following Monday, both the project officer and the foreman were on site. Some of the men considered that alignment of the towers could only be achieved with great difficulty, involving the use of anchors and chain hoists. John Lea, the field engineer who was project officer for the tower construction, demonstrated on the first tower how minor adjustments could be made by alternately tightening and slackening the guys. The crew then made minor adjustments to the second tower, and the permanent cross-arm pins were fitted to Towers 1 and 2. The project officer left the site at 11.00 a.m., leaving the foreman in charge. The foreman left a few minutes later, having been called to an interview at ETSA headquarters. None of the senior linesmen present was instructed to take charge. The absence of supervisors was not without precedent; it had been accepted practice at ETSA that provided workers had been properly briefed, the continuous presence of a foreman or engineer at a worksite was not mandatory.

After lunch, four workers climbed Tower 3. The crossarm remained secured to the legs with temporary bolts and rope. The incorrectly positioned guy wire on one of the tower's legs impeded proper alignment of the structure. The crew rigged an additional guy made of polypropylene rope to an adjacent point on the leg, secured it with a tarpaulin hitch, or 'truckies' knot', and released the incorrectly positioned wire guy. As the guy was being repositioned, the other leg of the tower began to move. A loud crack was heard, as a bolt connecting the cross-arm to the tower's western leg sheared. The moving tower leg stopped, but only momentarily. The entire structure then crashed to the ground. The state coroner found that the polypropylene guy rope had failed because of tensile overload, either through simple stress or through slippage of the 'truckies' knot' (Gordon 1982, p. 11).

The four workers, whose ages ranged from twenty-eight to thirty-nine, were tied to the towers by safety harnesses and crashed to the ground along with it. Three died instantly; the other, evacuated by the state rescue helicopter, was pronounced dead on arrival at Royal Adelaide Hospital. The Coroner's report reflects the violence of each of the men's deaths: cerebral lacerations due to ruptured skull; intra abdominal haemorrhage due to ruptured mesentery and lacerations to liver; cardiac temponade due to traumatic rupture of the ascending thoracic aorta; traumatic rupture of the brain stem due to fracture dislocation of the atlanto-occipital joint at the base of the skull (Gordon 1982, p. 1).

A number of defects in the planning and execution of the project contributed to the fatal accident. There had always been a degree of rivalry between departments in ETSA, and the Distribution Branch had traditionally seen itself as autonomous, requiring little or no assistance from other parts of the Organisation. There appears to have been insufficient liaison between those ETSA officers who designed the towers and those who were to construct them. The Coroner's report faulted the Trust for failing to incorporate construction considerations in the design of the towers. Admittedly, the conventional 'Stobie poles' were rejected early on. But in the words of the Coroner:

Having regard to the nature of the terrain and the comparative novelty of the towers to the officers of the Trust it is surprising that the means of erection was not given more detailed consideration before the towers were finally decided upon (Gordon 1982, p. 3).

This was not the first occasion in the history of the Trust when a serious accident had resulted from imperfect communications between design engineers and field personnel. In 1967, a linesman fell and was injured whilst changing an insulator string on a tower just south of Port Augusta. The weight of the conductor, which was supported on a chain lever hoist connected to the bottom member of the tower crossarm, caused the member to fail. Since that time, Trust engineers involved in the design of transmission structures continue regularly to emphasise the danger of loading such members in a manner which would cause failure (Sykes, L. 1987, pers. comm., 11 June).

The task force of linesmen were skilled and experienced professionals. The four deceased had worked for ETSA a combined total of 48 years. Even the least experienced of the four was a 6-year ETSA veteran. Nevertheless, certain aspects of the project were without precedent for them. Their expertise lay in maintaining towers, not in building them. None was experienced in construction operations involving a helicopter. None had worked previously on a guyed aerial structure. Although the men on the tower and ground personnel were equipped with two-way radios, the noise of the helicopter rendered the communications equipment useless.

Presumably ETSA could have contracted the project to a company experienced in aerial construction. But there was a certain pride attached to being able to do one's own work. While the men involved in the project were volunteers, there was some suggestion of pressure to ascend the towers:

It is easy to make it look like you were volunteers, but men on the ground were told that the job had to be done. We weren't told at that time that if none of the men were prepared to do it, then the job would be called off. We felt compelled. Someone had to do it. Fair enough if that's volunteering. I volunteered... (South Australia 1982, p. 300).

The erection of a guyed structure entailed certain engineering principles unfamiliar to the linesmen. Alignment of the towers could be achieved by relaxing and tightening various guys. Whilst this was demonstrated on the morning of the accident, a number of workers were absent from the briefing. In addition, the different tensile strengths of rope and steel guys render them incompatible within the same structure. The rule that 'rope and wire do not mix' was either unknown to the men or went unheeded. Their use together violated the basic principle that a guyed aerial structure be steadied by equal and opposite forces. The truckie's knot, which is prone to slip if not properly secured, and which places inordinate strain on the rope, compounded this risk. The use of truckies' knots was common, if unorthodox procedure within ETSA. The linesmen, generally unaware of these engineering considerations relevant to the unusual construction task at hand, were not properly instructed. They remained ignorant of the engineering principles themselves, and of the rationales for them. Had they realised that all they needed to do to correct the eccentricity was to slacken the temporary wire guy, the accident would probably not have occurred.

One further oversight was the failure to check the positioning of the wire guys at the tops of the tower legs prior to the actual erection of the tower. In fact, the eccentricity in the tower's position which was caused by the incorrect positioning of the guy wires made it extremely difficult to fit the cross arm, and thus contributed to the circumstances giving rise to the tower's collapse (Gordon 1982, p. 7).

The Coroner was critical of what he regarded as the inadequate briefing of the linesmen:

The situation called for something more . . . than would be usual work engaged in by linesmen. Careful and detailed explanation of the whole project, together with specific instructions as to the duties of each man, was called for.

I am satisfied that instructions were given on Thursday, 10 September when the towers were being assembled in the carpark. But this was largely work which the men had not previously performed. It is unlikely that they could have assimilated and recalled all the detail required despite the discussions that took place during these briefings.

Furthermore, there is considerable doubt that all or even a majority of the linesmen were present on all occasions when a matter affecting their safety did arise and explanation, advice or directions were given by the area engineer, project officer or the foreman, or that important instructions were clearly and firmly given (Gordon 1982, p. 6).

By far the most crucial factor, however, was the lapse in supervision. The foreman had been called back to ETSA headquarters to attend an interview. In his report, the coroner criticised a 'lack of communication between those responsible for the oversight of this project and other areas of the Trust's administration' (Gordon 1982, p. 12). No-one had been designated to act in a supervisory capacity in the foreman's absence. The foreman's immediate superior, the Project Officer/Field Engineer was in his office at the time of the accident, having left the site earlier unaware that the foreman was absent from the construction site. At the Coroner's inquest the foreman admitted '[t]his accident would not have happened if I had have been present' (South Australia 1982, p. 149).

In theory, ETSA was subject to the regulatory oversight of the South Australian Department of Industrial Affairs and Employment (as it then was) regarding matters of occupational health and safety. In practice, the Department deferred to ETSA's self-regulation, and made its services available on request. The Trust was, after all, a large, professional engineering Organisation with a traditionally impressive safety record. With a work force of over 5,300 it was one of South Australia's largest employers. The limited resources of the state's health and safety inspectorate were thus devoted to the oversight of less reliable enterprises.

The accident triggered the standard official response to multiple fatalities. Inspectors from the Department of Industrial Affairs and Employment began an investigation. The Trust itself began an internal inquiry undertaken by senior engineering personnel. The state police accident investigation squad also became involved. The following March, the state Coroner held an inquest. The experience was a painful one for the widows of the deceased; three of them left the court during a demonstration on a model of the fatal tower for the purpose of illustrating the method of collapse (The Adelaide Advertiser 31 March 1982, p. 3).

Initially, there was some inclination to fix blame on the site supervisor, and to deny corporate liability. But ETSA accepted the advice of its solicitors that it was responsible. On the third day of the Coroner's inquiry, and some six months after the accident occurred, ETSA admitted full responsibility at civil law. Widows of the deceased linesmen brought actions against the Trust under the Wrongs Act 1936-1975 (SA). The last of these was finalised three years later, in April 1985. In that case the plaintiff was awarded a judgment in the sum of $254,850.40 (Bahr v. Electticity Tnist of South Australia 39 SASR 1983 [1985]).

On 24th August 1982 ETSA was charged with a breach of Section 29 of the Industrial Safety, Health and Welfare Act 1972-81 (SA). Commonly referred to as the 'general duties' provision of the Act, Section 29 requires an employer to take ,all reasonable precautions to ensure the health and safety of workers employed'. The particulars of the complaint specified that the defendant failed to provide staff to supervise the work force after 11.30 am on the day of the accident.

The matter was heard in the Adelaide Industrial Magistrates' Court on 23rd September 1982. Section 29 had been amended in 1976 to increase the maximum fine which could be imposed for an offence under the general duties provisions from $250 to $500.

Counsel for ETSA entered a plea of guilty, and the Trust was fined $250 plus $15 court costs (Pyne v. ETSA, Industrial Court of South Australia 82/39554-6, 29 September 1982).

The accident brought home to ETSA management the shortcomings of existing training practices. ETSA now issues detailed instructions for each engineering job, and provides each linesman with a manual which details acceptable practices and procedures. Such protocols were previously required only for high voltage and live line work. Since the accident in 1981, every project involving new or unusual procedures must be thoroughly documented, and all personnel briefed in advance of the work. There is now greater co-ordination between the different ETSA departments which are involved in the various stages of construction work and other hazardous projects. Structures under construction are now routinely inspected according to defined procedures. Supervisors are required on site whenever work is in progress. And the Trust no longer uses helicopters for structural or construction work.

References

  • Gordon, L. 1982, Coroner's Report Concerning the Deaths of P.R. Stoddard, C.J. Bahr, M.H. Foale and P.D. Pike, Coroner's Office, Adelaide.
  • Lea, J., Aikin, K. & Kutcher, R. 1981, Detailed Job Briefing - Erection of Guyed Towers, Waterfall Gully, Department of Labour, Adelaide.
  • South Australia 1982, Proceedings of Coroner's Inquest Concerning the Deaths of P.R. Stoddard, CJ. Bahr, M.H. Foale and P.D. Pike, Coroner's Office, Adelaide.