Section 9

ORIGINATION OF FIRE 

Engine fires in general 

SECTION 9. CAUSES OF FIRE 

9.1 The Board examined a number of reports concerning MMS fires.[e.g. E21, 

E253, E254] Fires in engine rooms are common and a number of flag states issue reports 

on such incidents. Amongst the material the Board has studied is the International 

Maritime Organisation (IMO) document FP 42/INF6, entitled ‘Analysis of Fire Casualty 

Records’, dated 13 October 1997 [E460], introducing and summarising a UK Maritime 

Safety Authority’s research paper into causes of fire in fuel systems. Australia is a 

member of IMO, which is an agency of the United Nations established by the Convention 

on the Intergovernmental Maritime Consultative Organisation 1948. IMO offers technical 

advice, consults and draft conventions and agreements on matters affecting international 

trade, maritime safety and marine pollution. 

9.2 The environment in which marine engines operate involves vibration and 

flexing of the ship in a seaway. This predisposes ship’s engines to some leaking of fuel 

and lubricating oils at joints and connections. In more modern marine diesel engines, 

problems with leaking fuel are not as great. Fuel pipes are sheathed and components 

placed in containing cofferdams to control minor leakage. Hot engine surfaces are 

shielded or lagged to minimize possible ignition sources. 

9.3 The presence of fuel oil, air and hot surfaces makes a ship’s MMS a relatively 

higher risk space for fire compared to other spaces in a ship. An operating engine 

generates great heat. Exhaust systems and unlagged indicator cocks are a potential source 

of ignition. 

9.4 Taking the propulsion system as a closed system (i.e. excluding an external 

source of ignition such as an electrical spark lighter or match), the greatest risk of fire is 

from: 

a. a fuel leak from either the low pressure or high pressure fuel lines or 

lubricating oil systems, spraying on to a hot surface; 

b. spontaneous ignition, originating in oil soaked lagging; 

c. an overheated bearing in a crankcase igniting the lubricating oil mist and 

causing a crankcase explosion; and 

d. carbon deposits within the scavenge or exhaust systems of the engine 

igniting. 

9.5 Statistics contained in the IMO document show that 50 percent of MMS fires 

originate from the low pressure fuel system piping and fittings. Other sources of MMS 

fires originating in the fuel system include: 

a. high pressure fuel piping (10 per cent); 

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CAUSES OF FIRE 

b. slack, fractured or removed studs/bolts (7 per cent); 

c. loose/unscrewed or fractured bleed cocks, screws or valves (7 per cent); 

and 

d. miscellaneous/undetermined fuel leaks (7 per cent). 

Ignition point and fuel source 

9.6 Detective Senior Constable WA Hawes is a member of the WA Police Arson 

Squad. He was part of a Disaster Victim Identification Team comprising officers from the 

Emergency Operation Unit, the Forensic Division and the Arson Squad which attended 

WESTRALIA at about 1830 on 5 May 1998. The team acted on behalf of the WA State 

Coroner and at the invitation of the Navy. 

9.7 Detective Senior Constable Hawes expressed the opinion in his Preliminary 

Report dated 14 May 1998:- 

The most probable explanation from the fire scene examination, is that diesel 

fuel has sprayed from the braided fuel line at unit 9, starboard engine onto 

hot engine parts. The diesel vapour has been heated to ignition temperature 

by this contact, self igniting and sustaining combustion.[E32] 

9.8 He explained in his evidence on 15 May 1998 why he termed his report 

‘preliminary’: 

With fire scene examination, this examination is one part of it. We develop 

theories as a result of our examination. These theories we test. A lot of that 

testing comes from witnesses, on their observations. At this stage, I haven’t 

been able to speak with all witnesses, so therefore all the information is not 

available to me.[T305-306] 

9.9 Detective Senior Constable Hawes adhered to his original hypothesis when he 

was recalled to give further evidence on 27 June 1998 and in his final report dated 15 July 

1998.[E452] When he gave further evidence he had had the opportunity to review the 

evidence of the witnesses who saw the start of the fire, namely, PO Hollis, PO Francis, 

LSMT Smith and LEUT Walters.[T2757] The evidence of the eyewitnesses made it clear 

that the fire started on the starboard main engine.[T583, T1242-3, T1459, T1806, T2802] 

That evidence, as well as scientific testing, confirmed Detective Senior Constable Hawes 

conclusions part of which he stated in his Preliminary Report as follows: 

HMAS ‘Westralia’ has suffered a major diesel leak on the inboard side of 

the port engine. This diesel has sprayed downwards 45 degrees towards the 

starboard engine, and created a diesel vapour cloud above the engines. 

Another diesel leak has occurred in the braided fuel line at unit 9 of the 

starboard engine. This has possibly sprayed upwards and outward due to the 

inner lining being exposed through the braided outer shell in a cone like 

shape.[T310] (Figure 10) 

147


Figure 10. Hose S9R. The inner teflon tube can be seen protruding through the 

wire braid in a fan shape. (Fig 48 of Metlabs report) 

Failure of PME supply hose (No. 8 cylinder) and SME return hose (No. 9 

cylinder) 

9.10 Detective Senior Constable Hawes made observations of, and with the 

assistance of WO Bottomley removed, certain flexible fuel hoses, as described in his 

report.[E452] The hoses were later more particularly identified and scientifically 

examined by Mr John Bromley, metallurgist (from AMEC Pty Ltd trading as Metlabs). 

Evidence before the Board disclosed that on 5 May 1998 two flexible fuel hoses had failed 

- namely, a supply hose on the PME, number 8 cylinder (P8S), and a return hose on the 

SME, number 9 cylinder (S9R). The second flexible fuel hose appeared to be the primary 

cause of the fire as the burst hose provided a source of atomised diesel fuel in the area 

where the fire was observed to start. A hot engine part nearby, probably an indicator cock, 

provided the source of ignition.[E452, T308-310; E227, T3419, T3546, T4073-4075, 

T4180] 

Secondary bilge fire and areas of fire damage 

9.11 There was evidence of a secondary fire in the bilge. This fire seemed to be 

confined outboard of the starboard engine, between frames 30 and 31, 7.650 m and 8.500 

m aft of the lower bulkhead of the after pump room.[E452] At bottom plates level, there 

was little damage to the polycarbonate light fittings, other than one immediately outboard 

and one forward of the apparent seat of the fire. The evidence is that at the bottom plates 

level, other than the area outboard of no. 9 cylinder, the temperature was relatively low, 

even during the most intense phase of the fire. 

9.12 Above this level, at the middle and top plates, more extensive damage could be 

seen. Light fittings had melted and heat damage involving the buckling of walkway plates 

148


and the melting of alloy sheets forming the backs of ladders. This damage indicated 

temperatures in excess of 600°C. The most extensive area of damage was on the underside 

of the MCR. All the cabling insulation had been destroyed. Substantial ‘I’ beams for the 

MMS hoist had been buckled. 

Other expert opinion 

9.13 Dr G Goodwin, a Senior Research scientist and engineer with the Defence 

Science and Technology Organisation, Maritime Platforms Division and Mr T P Casey, 

consulting scientist and engineer, also agreed with Detective Senior Constable Hawes’ 

hypothesis.[E214 para 38, E228]. 

9.14 Mr G M Kelly, a fire investigator, was somewhat equivocal: in his opinion 

there was ignition by an unidentified source of flammable liquid vapour originating from a 

diesel leak(s) from an unidentified source.[E227] 

9.15 Mr P E Burge, a marine engineer, whilst canvassing other possible ways in 

which the fire may have started, accepted that the most probable cause was that the fire 

started with the bursting of the starboard no. 9 cylinder return hose (S9R), the spraying of 

fuel onto a heat source and igniting, as described by Detective Senior Constable Hawes in 

his Preliminary Report.[E224 para 13.1, T4077-4087] 

9.16 Mr Burge ultimately advanced two possible alternative causes of the fire:- 

The vapour cloud from the port engine may have been drawn into the turbo 

charger of the starboard main engine where it ignited and thus internal fire 

melted the aluminium scavenge ducting. The heat in the duct may have 

affected the hose immediately beneath it and weakened the hose structure 

sufficiently to cause a rupture. Fuel under pressure would then have sprayed 

vertically into the hot parts of the duct and also ignited.[E224 para 13.2] 

The oily mist atmosphere within the crankcase may have been ignited from 

an internal heat source and been released into the engine room. This heat 

could have ignited any loose fuel or fuel vapour in its vicinity.[E224 para 

13.4] 

9.17 In his evidence before the Board, as to the first of those possible alternative 

causes of the fire, Mr Burge accepted this as being no more than a possibility [T4083-4] 

Mr Bromley conducted a metallurgical assessment of the scavenge ducting (also known as 

a charge air rail or inlet manifold) and concluded that the source of the fire where the 

ducting had melted adjacent to starboard 9 cylinder was external.[E398] There was no sign 

of a fire having occurred internally or of an explosion. Even if an explosive mixture had 

been drawn into the scavenge ducting there was no material within the scavenge ducting to 

sustain the fire to raise the aluminium to melting temperature. 

9.18 Similarly, Mr Burge did not press the second alternative as anything more than 

a possibility because of the fact that there was a Gravenor alarm which should have gone 

off had there been a crankcase explosion, but did not; that there were signs only of a small 

amount of oil leaving the engine (and these signs may have preceded 5 May 1998); and 

that there were probably flame traps behind the crankcase doors.[T4086] CMDR Irwin (an 

engineer) advised the Board:- 

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Fuel specification 


I even question whether there was an explosion at all but rather a raise in air 

pressure inside the crankcase caused by the heat.[T3495] 

9.19 Analysis of the fuel oil showed that its closed cup flash point was 71°C and 

auto ignition temperature was about 310°C.[E311] The fuel was within specification and 

there was nothing inherent in it which lead to it being a greater hazard than the engine 

design allowed for. 

Ignition source 

9.20 A probable source of ignition was the adjacent indicator cock (Figure 11). The 

indicator cock was not lagged or shielded and could reach temperatures in excess of 450 ο C, 

well in excess of the 310°C auto ignition temperature established in testing the fuel sample. 

Figure 11. A view of the fire damage to the outboard side of the SME showing 

the indicator cocks at cylinders 8, 9 & 10. (Mr G. Kelly) 

Fuel supply 

9.21 The fuel to the burst return line on the SME was initially supplied under 

pressure from the fuel boost pump via the injector pump chambers linking the supply and 

return ports. The prompt shut down of the engine isolated this source but the design of the 

system is such that fuel can be supplied under pressure due to gravity from the service tank 

by means of the return line. The incorrectly fitted and defective back pressure valves 

would have presented no barrier to the fuel flow.[E480] The service tank was isolated by 

the EOOW at some time between 1048 and 1053.[E91, p10 & p12] Some fuel may have 

continued to flow, albeit at a greatly reduced rate, as the fuel lines from the service tank 

drained. This final phase of the fuel supply to the fire was not tested. 

150


9.22 Examination of WESTRALIA’s liquid cargo chits[E80] gives no indication of 

the fuel oil that may have been consumed by the fire. The dips taken on 14 May 1998 

show marginally more fuel onboard than on 5 May 1998, although no fuel oil was later 

taken onboard in the intervening period. 

Conclusion 

9.23 The Board accepts the hypothesis of Detective Senior Constable Hawes as 

to the start of the fire and finds that the fire started as a result of the ignition of 

atomised fuel from a leak in the new flexible return hose on no. 9 cylinder on the 

starboard main engine (S9R). The Board finds that the possibility of some other 

source of the fire is not sustained by the evidence. The source of the ignition was 

probably the adjacent indicator cock on no. 9 cylinder. It seems that fuel may have 

continued to supply the fire for at least 15 minutes at a diminishing, and relatively 

small, rate. 

FAILURE OF THE FLEXIBLE FUEL HOSES 

Description of the hoses 

9.24 The flexible fuel hoses were made from lengths of a hose which comprised a 

teflon inner tube covered by a stainless steel wire braiding containing seven wires or 

strands per braid. Fittings were attached at the end of the hoses. 

9.25 The supply hoses and return hoses had an exposed hose length of around 

140mm and around 160mm respectively. According to a product sheet (which was not 

given to ADI or Navy) the hose had, amongst others, the following specifications [E197 

Tab 4]: 

Diameter of Bore ¾ inches 19mm 

Working Pressure 800psi 5.5MPa 

Minimum Burst Pressure 3500psi 24.1MPa 

Minimum Bend Radius 9 inches 229mm 

Hours of operation of the flexible fuel hoses 

9.26 WO Bottomley, stated that he believed that although the flexible fuel hoses 

were installed on 10 April 1998, the main engines were not operational until 22 April 

1998.[E209] The daily TM 136 logs for the period 21 April - 5 May 1998 indicate that the 

SME had operated for approximately 39.5 hours, and the PME for approximately 36 hours, 

from the time of hose installation to the time of the fire.[E209, T3418-9] 

Metallurgical testing of flexible fuel hoses 

9.27 The flexible fuel hoses were all removed from WESTRALIA’s engine for 

testing in the course of this Inquiry. Mr Bromley, was appointed by the Board to 

independently conduct an analysis of the integrity of the hoses.[E194A] 

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Failure of flexible fuel hoses due to fatigue 

9.28 Mr Bromley confirmed that all the hoses, with the exception of two, showed 

random, isolated fatigue features of several wires. In particular, he confirmed that: 

…the two hoses which failed, the supply hose on port 8 cylinder (P8S) and 

the return hose on starboard 9 cylinder (S9R), had ruptured as a result of 

internal pressurisation due to the fact that approximately 50 adjacent wires in 

5 to 7 braids had fractured as a result of prior fatigue cracking, leaving the 

internal teflon tube unsupported and hence unable to support the normal 

working pressure.[E194A p24] 

9.29 Another hose, P12R, was found on examination to have hose characteristics 

and a wire fracture disposition similar to P8S and S9R. 

9.30 Mr Bromley stated in his report that the production of fatigue cracking in the 

wires in the hose would require prolonged exposure to an alternating stress, which in the 

hoses would be consistent with a variable pressure induced by the (fuel) injector pump. 

Further, the damage in the three hoses in which adjacent braids were fractured suggested 

that these hoses were subjected to more severe fatigue conditions either due to an increase 

in internal pulsating pressure or an increased stress concentration produced as a result of 

more radical mechanical damage sustained in prior use.[E194A p25] 

Figure 12. The SEM photo of the fracture surface of the wires from the used fuel 

line, identified as: P5R 491/16, which was burst in testing, showed the 

fatigue markings present on smooth flat fracture face and the absence 

of any bulk thinning (scale - 100 microns). (Fig 32 Metlabs report) 

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9.31 Compare figure 12 above, which shows a classic fatigue failure, with the 

following photograph (Figure 13), which shows a pressurisation rupture, induced by 

hydro-testing to failure. The wedge shaped fracture surfaces in several wires are 

associated with tensile failure. 

Figure 13. The SEM photo of the fracture surface of the wires from the used fuel 

line, identified as: P5R 491/16, which was burst in testing, showed a 

necked, wedge shaped fracture on the wires at the rupture (scale = 

100 microns). (Fig 33 Metlabs report) 

9.32 The results indicating that the hoses failed due to fatigue are not controverted 

and are basically accepted by the other experts.[Goodwin E214 para 43; Burge E224 para 

16.2; and Casey E228 para 6.5] 

Conclusion 

9.33 Flexible fuel hoses S9R and P8S failed by reason of fatigue of the stainless 

steel braiding. 

Other testing results 

9.34 Selected hoses were pressure-tested to destruction. Only one, P12R (noted 

above as a hose with characteristics and a wire fracture disposition similar to P8S and S9R) 

failed at less than the manufacturer’s stipulated burst pressure.[E194 para 11] Mr Bromley 

also concluded that hoses P8S and S9R would have ruptured at less than expected 

pressure.[E194 para 24] 

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9.35 On examination, there were signs of mechanical damage to many hoses, 

particularly permanent sets and internal creases. These were found not to significantly 

affect the static burst strength.[E194 pp8 and 25] 

9.36 In order to test the possibility that damage sustained during installation and/or 

reinstallation contributed to the failure of the flexible fuel hoses, a sample hose, identified 

as ‘D’, was gripped using a pair of multigrips and severely twisted and bent in order to 

produce major damage. Extensive internal and external deformation occurred with the 

production of scoring and denting but only one obvious fracture of a wire.[E194 para 3.13] 

Hose D was then pressure tested and failed at just under the minimum specified burst 

pressure.[E194 para 4.1.3] This testing was video-recorded and shown to the intervening 

parties. 

Figure 14. The recently assembled unused fuel line, identified as D, was 

extensively twisted and bent, producing permanent distortion, 

abrasion and a broken strand. (Fig 26 Metlabs report) 

Conclusion 

9.37 The Board is satisfied that the results of the metallurgical testing indicate 

that any mishandling, if it occurred during or after initial installation, did not 

contribute in any significant way to a major reduction in the burst strength of the 

hoses. 

Spill pulse pressure 

9.38 What caused the flexible fuel hoses to fatigue? Dr Goodwin is regarded as 

DSTO’s resident consultant on diesel engine matters. Dr Goodwin was of the opinion that 

the only likely cause of fatigue failure in the flexible fuel hoses was pressure pulsation 

originating at the fill and spill ports of the injector pumps.[E214 para 41] Mr Burge was in 

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agreement with Dr Goodwin as to the phenomenon of fuel pump ‘feedback’ pressure 

pulses (as he referred to them) and which he further described in his report as follows:- 

In WESTRALIA’s engines, the sharp release of fuel oil under high pressure 

from the fuel pump plunger through the spill orifice (port) into the annular 

groove which is machined into the pump body and which forms the common 

fuel inlet/return gallery, results in pressure shock pulses which are felt in 

both the fuel supply and return systems.[E224 para 7.1] 

9.39 The magnitude of the peak value of these pulses would be at least of an order 

of magnitude greater than the background pressure of the system but of unknown 

limits.[T3508-3520, E214D, E401(ER401 para 7.6), T4135-9]. Mr Burge pointed out in 

his report:- 

The British MSA Research Paper 401 in Clause 8.1.5 indicates that the peak 

pressures of the ‘feedback’ pulses within a fuel reticulation system could 

range between 41 Bar and 80 Bar and that the pulses are less significant if 

the light MDO is used rather than HFO. WESTRALIA uses MDO. In this 

letter dates 20 May 1998 the manufacturers agents, Rolls-Royce, have 

suggested that the magnitude of the pulses could be as low as 30 Bar (435.1 

psi or 3,000kPa) and as high as 70 Bar (7000 kPa or 1015.30 psi). I have not 

been able to find a definitive industry statement about ‘feedback’ 

pulses.[E224 para 7.6] 

9.40 The magnitude of the pulses would affect the minimum acceptable burst 

pressure and the frequency of the pulses would need to be considered for its effect on the 

fatigue life of the pipes and, for example, a letter from Rolls Royce dated 15 May 1998, 

states at paragraph 3: 

The design of all supply pipework and the associated fitting must recognise 

the above service conditions. The design criteria has to encompass 

appropriate margins for both the peak pressure and the potential fatigue 

aspects arising from the high frequency of the applied pressure pulses. The 

design as originally supplied fulfilled the above requirements.[E181] 

9.41 Dr Goodwin was of the opinion that the hoses had been selected with a safe 

margin over the background pressure, but that the evidence indicated that no consideration 

had been given to the pressure pulses. 

Number of pulses 

9.42 According to the expert evidence provided to the Board, 1 million stress 

reversals or pulses could bring about the fatigue fractures evidenced on the braid of the 

hoses.[Bromley T3252, Goodwin T3514] 

9.43 The two Pielstick PC2.2 engines in WESTRALIA: 

a. have 14 cylinders (7 cylinders in each bank); 

b. operate at a constant 500 revolutions per minute; and 

c. each cylinder fires once every two revolutions.[T3513-5] 

155


9.44 By way of illustration, a simplified way to estimate the likely frequency of the 

pulse for the whole engine, ignoring pulse reflections, can be calculated as follows: 

Number of cylinders × Revs per second 

Pulses per sec = 

Rate of cylinder firing 

14 × 8.33 

= 

2 

= 58 pulses/sec [407] 

9.45 Although not definitive, this calculation suggests that the flexible fuel hoses 

were coping with a potential 58 pulses per second. On this basis, WESTRALIA’s engines 

would have had to operate only for a short amount of time, in the order of 4.76 hours, to 

reach 1 million pulses. 

Conclusion 

9.46 Sufficient pressure pulses to cause fatigue failure of the braiding could 

easily have been generated since installation of the flexible fuel hoses. 

Pielstick, IMO and other information relating to ‘spill pulse’ 

9.47 The Board received evidence that from the early 1970s, the ‘spill pulse’ 

phenomenon had been known to the manufacturers of Pielstick engines, their licensees and 

others in the marine diesel industry.[E214D, T4141] Any modification of the fuel delivery 

system needed to encompass appropriate margins for both peak pressures and potential 

fatigue aspects arising from the high frequency of the applied pressure pulses.[E181] 

Pielstick Service Bulletins 

9.48 In Service Bulletins which it issued, Pielstick engine agents, NEI Crossley 

Engines (now part of Rolls Royce PLC) identified a high spill pulse or pulse spiking as a 

feature of the Pielstick engines, or more particularly, the jerk injection fuel pump system 

incorporated with the engine.[E189] 

Pielstick Service Bulletin 51 [E189] 

9.49 On the subject of fuel pump isolation cocks in PC2.2 and PC2.3 engines, 

Pielstick Service Bulletin 51 was issued on 2 September 1991. The last paragraph of page 

one of the bulletin states as follows: 

On all these cocks there has been leakage due to incorrect fitting of the ‘O’ 

rings. It was therefore replaced by a ball valve (PC16677) Fig IV. This 

valve has been satisfactory in most installations, but with certain fuels the 

pulsating load [emphasis added] in the fuel main has caused failure of the 

seats. 

9.50 Page 2 of the Bulletin introduced a new cock (PC196818) for use on all 

engines from serial number18152 onwards and warned: 

It is vitally important that the valve is screwed firmly on to the lower set 

when closed and on to the upper seat when open. In other words, the valve 

must not be left in an intermediate position, where the high pressure pulses 

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[emphasis added] from the fuel injection pump will damage the seats. In 

either direction, opening or closing, the valve spindle must be turned until 

resistance is felt, indicating contact with the seat and must not be backed-off. 

9.51 Clearly printed along the side and across the bottom of each page of each 

Pielstick Service Bulletin (including each page of bulletins 51 and 78) is the phrase, ‘This 

data is important to service engineers, operators and maintenance staff’. 

Pielstick Service Bulletin 78 [E58 Tab 7, E189] 

9.52 Pielstick Service Bulletin 78 also dated 2 September 1991 advised that 

Pielstick had developed a system whereby flexible fuel hoses could be fitted to the engines. 

However, the flexible fuel hoses were part of a general package of modifications which 

took into account the spill pulse phenomenon. Pielstick Service Bulletin 78 stated that the 

engine makers should be contacted for details and advised of the availability of pulsation 

dampers which ‘reduce the spill pulse to an acceptable level’.[E58 Tab 7] 

Criticism of Pielstick Service Bulletins 

9.53 Criticism was made of the sufficiency of the references to spill phenomenon in 

these Bulletins in the closing addresses on behalf of ADI [T4359] and Parker Enzed 

Technology [T4434] In his evidence, Dr Goodwin conceded that it would have been 

appropriate for the Bulletins to have included a warning about the phenomenon.[T3538] 

9.54 As will be developed in Section 10 of this Report, neither ADI (nor the other 

intervening parties) nor for that matter, the Navy gave any consideration to the Bulletins, 

let alone enquired of the engine agents concerning it. The appropriateness of enquiry of 

the engine agent’s was emphasised by Dr Goodwin:- 

Conclusion 

…I just wonder if, in your opinion, a professional engineer had been asked 

to comment on a proposal to change from rigid fuel hoses to flexible fuel 

hoses in a particular type of engine, he might have actually seriously 

considered ringing the engine manufacturer to get some advice? 

…Absolutely. I think the first thing I’d have done is to delve into literature 

and go for a library search and probably on the second day I’d have thought, 

‘Why don’t I ask the manufacturer?’ I think an engineer who was more 

inclined to be doing this work on a routine basis as modification, I think he’d 

have run to the manufacturer first.[T3575-3576] 

9.55 Regardless of the quality of the information contained in the Pielstick 

Service Bulletins, information on the subject of spill pulses was available from the 

Pielstick engine agents, NEI Crossley Engines, at the time of AMP 12. Even a cursory 

examination of the Bulletins should have alerted a reasonably competent engineer to 

the existence of the spill pulse phenomenon and should have aroused sufficient 

curiousity in any technical person to make further enquiry. A reasonably competent 

engineer would have given the phenomenon due consideration and would have 

communicated with the engine agents. Indeed, any technical person who was charged 

with having the flexible fuel hoses manufactured and installed should have 

communicated with the engine agents. 

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International Maritime Organization (IMO) documentation 

9.56 The issue of shipping industry awareness of the effect of spill pulses is also 

supported by the content of documentation issued by the International Maritime 

Organization (IMO). 

IMO Paper 1994 

9.57 IMO Marine Safety Committee Circular (MSC Circ.647) entitled, ‘Guidelines 

to Minimize Leakages from Flammable Liquid Systems’ was issued on 6 June 

1994.[E462] In relation to the design and construction of hose and hose assemblies MSC 

Circ. 647 states as follows: 

IMO paper 1997 

Hoses should be constructed to a recognized standard and be approved as 

suitable for the intended service, taking into account pressure, temperature, 

fluid compatibility and mechanical loading including impulse (emphasis 

added) where applicable.[Appendix 2, p 5, para 3] 

9.58 The UK MSA research paper of January 1997 referred to in the IMO paper 

reference FP42/AMF6 dated 13 October 1997 dealt extensively with the phenomenon. 

Paragraph 8 of the IMO paper stated:- 

Conclusion 

High pressure pulses lead to vibration and fatigue…The failure of fuel lines 

and their components will invariably involve fatigue and the initiation of 

fractures due to tensile stress.[E460] 

9.59 The Board is of the view that information concerning the spill pulse 

phenomena was available and accessible had it been sought. It was not sought. 

Awareness of spill pulse by sea-going engineers 

9.60 Dr Goodwin attended a meeting on 3 July 1998 held at Wartsila-NSD Australia 

(Wartsila) in Sydney, where, amongst other things, awareness of spill pulse was 

discussed.[E401, T4141] Dr Goodwin stated in evidence that at this meeting:- 

…there was a general consensus that the industry normally deals with these 

pulses, and not knowing their magnitude, by simply over-engineering and 

using much, much stronger pipes than you would need to use for the nominal 

set pressure. And it became clear to us, I think, that several of the people 

there thought that everyone ought to be aware of these pulses…[T4141] 

9.61 Dr Goodwin gave evidence that on 7 July 1998 he telephoned Mr Eric Clarke, 

General Manager, Wartsila, with a view to confirming whether their knowledge of spill 

pulse arose as a result of their marine engineering training or the work experience they had 

in recent years. Mr Clarke told him that he was trained in England about 24 years ago. He 

assured Dr Goodwin that a full description of the fuel systems of diesel engines was 

explained in those courses and that he was made aware of the characteristics of jerk pumps 

and the sort of signals they produced. Mr Clarke expressed the opinion, that anyone who 

had completed the kind of course he had, would be similarly aware.[T4141-2] He also 

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spoke to Mr Jeff Cleary, Wartsila’s Service Engineer, who had previously spent 9 years 

teaching marine engineering at Sydney Institute of Technology. According to Dr 

Goodwin, Mr Clarke told him that in his opinion:- 

…anybody who had a Dip. Marine, an advanced Dip. Marine or a first-class 

marine engineering certificate involving engines – that is the motor part of 

those qualifications – should be well aware of the effect of spill 

pulses.[T4142] 

9.62 As a result of these discussions, Dr Goodwin stated that:- 

Last week I was prepared to say it was clearly well-known in the engine 

industry, but this evidence seems to me to show it’s well-known amongst 

sea-going engineers in the merchant navy . . . Navy maintainers, at least now 

in some arms of the Fleet, are not being trained for heavy maintenance work 

and they probably would have to have the kind of training that a sea-going 

chief engineer in the merchant navy would have. Given also that Navy 

training is also done by senior sailors and engineering officers who’ve come 

through the Navy training system themselves, I suspect there may be a 

serious gap in Navy training in this area and that’s why I think the Naval 

staff may be unaware of things that the merchant marine sea-going engineers 

should be aware of.[T4143] 

9.63 Mr Burge’s evidence was that his inquiries indicated, amongst other things, 

that the effect of spill pulses was not well known and in particular it was not taught in the 

marine engineering school at the Marine Centre South Fremantle TAFE College.[T4372] 

Conclusion 

9.64 Marine engineers with qualifications acceptable to the Merchant Navy 

would probably have been aware of the nature of pulses caused by jerk pumps, if not 

the full extent of spill pulse pressure. 

9.65 Neither Dr Goodwin nor Mr Burge have relevant expertise on the subject 

of RAN marine engineering training. The purpose of RAN marine engineering 

training is not to develop expertise in all aspects of engineering design but is more 

targeted at machinery operation, accordingly, knowledge of ‘spill pulses’ is not an 

essential training requirement. Appropriate experts in industry are usually used for 

deep specialist skills. 

Outstanding issues between experts 

9.66 The Board has been significantly assisted by the evidence of Dr Goodwin and 

Mr Burge. By the end of the hearing, Dr Goodwin and Mr Burge were in substantial 

agreement, with the exception of two issues: 

a. the possibility of relevant over pressure in the fuel hoses occurring as the 

result of some malfunction in the fuel system [E224 paras 14-15]; and 

b. the extent of knowledge of the spill or feedback pressure in diesel fuel 

hoses from high pressure fuel pumps. 

The second of these issues has already been addressed above. 

159


Overpressure occurring due to fuel system malfunction 

9.67 ADI suggested that the hose ruptures may have been caused prematurely by a 

pressure surge operating on degraded hoses. This surge was indicated by defects on three 

fuel system pressure gauges.[T517, T4385] 

9.68 Dr Goodwin viewed the gauges as photographs and gave evidence on the 

issue.[E135, T3516-3120 and 3567-3570] In commenting on Mr Casey’s report [E228 in 

E401-ER031], Dr Goodwin stated that he was not convinced that any of these (fuel 

gauges) related to real overpressures and that one had failed by partial vacuum. Dr 

Goodwin did not place much credence in the evidence of the gauges. He stated that the 

MCR repeater was reading an electrical signal from a pressure transmitter near the fire and 

that this was far more likely to be an artefact of a measuring system in an overheated state. 

Dr Goodwin concluded that even if there was a real overpressure, it may have been by 

overheating of a ‘dead leg’ of pipework attached to the gauge during the fire. 

9.69 Whilst the failed gauges do not feature as such in Mr Burge’s conclusions, 

those conclusions in paragraph 16.3 refer to ‘excessive surge pressure’ and include these 

two paragraphs: 

16.4 There is insufficient data to determine the characteristics of the forces 

which had caused the fatigue failure in the ruptured flexible hoses. A range 

of engineering analyses and tests needs to be conducted to establish the 

precise nature and extent of these forces. 

16.6 To the extent that aspects of this report are inconclusive, it is because 

of a lack of data available about the status of elements in WESTRALIA’s 

engine operating systems.[E224] 

9.70 Mr Burge’s attention was drawn to Dr Goodwin’s evidence on the failed 

gauges during his oral evidence. Mr Burge spoke of gauges ‘wildly fluctuating’ but 

accepted the possibility of the damage to the gauges occurring after the fire.[T4104-4106] 

9.71 In a letter to the Board, from ADI’s solicitors it was submitted: 

What is clear from the Metlab’s report is that fatigue damage to 53 fuel 

supply and return hoses did not render the hoses unfit for their purpose and 

they continued to function entirely satisfactorily up to the point where the 

main engines were declutched. Three of the hoses examined showed 

evidence of degradation which was sufficiently severe as to expose the hoses 

to the risk of rupture when subjected to abnormal pressure. The degradation 

was caused either by localised abnormal pulse pressure or mechanical 

damage. But for the abnormal pulse pressure or the mechanical damage it is 

highly probable that the hoses would not have failed and would have 

remained fit for their purpose at all material times.[E214E] 

9.72 Dr Goodwin was asked to comment on the ADI assertions.[T3521-3522] He 

replied as follows: 

The first sentence says that the fatigue damage to 53 hoses didn’t render the 

hoses unfit for purpose. I’m not sure what the meaning of that. There were 

56 hoses. If any one of them fails a dangerous situation arises. So there was 

by reductio ad absurdum; for example, you wouldn’t think an aircraft wing 

was strong enough if only one of them fell of and that’s sort of - - that’s an 

analogy. I mean, the fact that 53 survived is not really a terribly important 

160


issue. The fact that three failed is the important issue, it seems to me. I 

think there’s a matter of fact here they can either function up to the point 

where the main engines were declutched - - that’s true of the 53, that’s right. 

It’s actually true of 54, I think, because the one that failed under test hadn’t 

failed at this point. I think where a lack of understanding is really shown 

here, in this, with respect - - I think there’s a misunderstanding here. When - 

- the second sentence refers to ‘exposing the hoses to risk of rupture when 

subjected to abnormal pressure’. I think there’s quite enough evidence before 

us to show that the large pressure pulses in the fuel lines of these pumps is 

not abnormal pressure. It may be pressure that’s very much higher than the 

nominal supply pressure; but the normal pressure for this engine is the 

nominal supply pressure plus the pulses that come from these pumps. That 

is the normal working pressure. It includes quite large pulses. Those pulses 

are part of the normal working pressure, but they don’t show in the nominal 

supply pressure. I think that’s an important distinction. So, the pulses are 

not abnormal at all. There’s plenty of evidence, I think, before us now that 

these pulses are regarded as quite normal in engines of this class. So, the 

degradation was caused by local pulses, but they weren’t abnormal pulses, in 

my opinion; and it’s possible that mechanical damage - - some of the hoses 

may have exacerbated the problem by providing sites for the initiation of 

fatigue cracks, but there doesn’t appear to be much of that damage, and there 

appear to be a lot of hoses which had a significant number of broken strands 

in fatigue where I don’t think there was serious mechanical damage.[T3521- 

3523] 

9.73 WESTRALIA has two oil fuel boost pumps located at the port side of the 

MMS on middle plates. They are mounted side by side, and designated ‘outboard’ and 

‘inboard’. The inboard pump is fed from the main switchboard via the starboard group 

starter board located in the MCR. The outboard pump has two sources of power. Its 

normal source is from the main switchboard via the port group starter board located in the 

MCR, while its emergency supply is from the emergency switchboard.[E212p1] 

9.74 At the request of the Board of Inquiry, the inboard fuel boost pump that was 

running at the time of the fire was removed from WESTRALIA and placed in a Watmarine 

Engineering Services (Watmarine) test rig. The fuel discharge pressure from the pumps is 

controlled by an integral recirculating valve sometimes known as the relief or control 

valve. The purpose of the testing was firstly, to check the setting of the control valve and 

hence the likely fuel supply pressure of the time of the fire and secondly, to determine the 

maximum pressure the pump could produce. This latter test was to see whether the pump 

was capable of producing the full scale deflection of the defective fuel system pressure 

gauges. 

9.75 Watmarine prepared a pump test certificate dated 29 June 1998 which showed 

the pumps performance characteristics.[E212 and T3491] 

9.76 In his report, CMDR Irwin commented that in the event of a zero flow (i.e. 

point of maximum output pressure for a positive displacement pump) situation, the pump 

was shown to relieve internally giving a maximum pressure of 625 kPa. After adjustment, 

the maximum output pressure the pump was capable of producing with the bypass closed, 

was measured to be 960 kPa.[E212(folio 333 para 3)] This is well below the full scale 

deflection of the defective gauges. 

161

Conclusion 


9.77 The fuel boost pump in use at the time of the fire was set at the correct 

pressure and was not capable of producing the full scale deflection pressure indicated 

by the defective fuel system gauges. 

9.78 Based on the expert evidence presented to the Board and the results of 

testing carried out on the fuel boost pump and pressure gauges, the Board prefers Dr 

Goodwin’s evidence on the subject of fuel gauges. The Board is satisfied that there is 

no evidence of a mechanism which could have produced an abnormal pressure pulse 

of sufficient magnitude to cause failure of the flexible fuel hoses. 

Other problems with flexible fuel hoses 

9.79 Apart from the spill pulse phenomenon, there are a number of other important 

design issues which were not considered. 

Bend radius 

9.80 Dr Goodwin gave evidence of a possible explanation for the signs of physical 

damage to many of the hoses.[R9.35] He advised that the bend radius of some of the 

return hoses appeared to be too small (ignoring possible additional bending during 

installation). In accordance with its product sheet, the minimum allowed bend radius for 

SST12 Astraflex hose is 9 inches.[E197 Tab 4] 

9.81 During his oral evidence Dr Goodwin stated that he had reviewed the hose’s 

bend radius by looking at photographs and taking measurements from a sample hose. Dr 

Goodwin stated that he was convinced that the bend radius was about 5.8 inches, which is 

substantially less than the minimum specified radius of nine inches. As a result, Dr 

Goodwin concluded that the hose was actually bent 25% more tightly in application than 

the specification allows.[T3502, T4131] While Dr Goodwin did not suggest that this was a 

cause of the fire, he thought it was an indication of inappropriate engineering 

design.[T3503] Dr Goodwin concluded that the SST12 hose could not be fitted in this 

particular location, to join the two connections points together, and meet its own 

specifications. In other words, it exceeded the allowed tightness of the bend.[T3504] 

9.82 In its closing address, ADI submitted that Dr Goodwin’s evidence concerning 

the alleged failure of the hoses to meet specifications as to the minimum bend radius was 

not free from doubt, given that the hose was not measured in situ, but measurements were 

taken from a sample hose and working from photographs, as well as his admission that his 

measurements were not very precise.[T4370] 

Conclusion 

9.83 Whilst Dr Goodwin’s measurements are not exact, they provide strong 

indications that the minimum hose bend radius requirements were ignored by the 

design. 

Fitting flexible hoses in a straight line 

9.84 Dr Goodwin gave evidence that hoses should not be installed straight.[T3506] 

Dr Goodwin based his statement on a text entitled Hose Technology by Colin Evans, 

162


published in 1974. The substance of Dr Goodwin’s evidence was that rubber or PTFE has a 

very different coefficient of expansion than that of iron or steel components and there 

needs to be room for it to move with thermal stress and changes of pressure. 

Consequently, if a hose is installed straight, it is likely to be under compression or 

tension.[T3506] Some examples of hose installation guidelines are shown in figures 

15-17. 

9.85 Measurement of the lengths of the hoses demonstrated some variability. In 

relation to the impact on the static loading due to different hose lengths, Dr Goodwin and 

Mr Bromley commented that if a static load, such as tension or compression, is added to a 

fatigue load then the hose loading situation is worsened.[Metlabs Report E194A pp3-7] 

Dr Goodwin formed the opinion that a short, straight hose was not a good design solution. 

Dr Goodwin also agreed with Mr Bromley that the straight arrangement provided no 

accommodation for different lengths of hose or different gaps to be bridged.[T3506] 

Mr Burge agreed that a combination of a wide gap and a short hose could put a hose under 

tension when the end fittings were tightened. Mr Burge further agreed that these 

conditions would have an impact on the loading of the braid and its susceptibility to fatigue 

damage.[T4103] 

Figure 15. E214C - Fig 34 from Hose Technology by Colin Evans 

163


Figure 16. Metallic flexible hose general installation guidelines issued in the 

Annex to MSC Circ. 647 - Figure 2.1. 

164


Figure 17. Non-metallic flexible hose general installation guidelines issued in the 

Annex to MSC Circ. 647 - Figure 2.2. 

165

Lack of means of restraint 


9.86 There is evidence that the return hoses were longer than the supply hoses, were 

curved and all had internal creasing.[T4103, T4131] The supply hoses were the straight 

hoses and the majority did not have creasing.[E401, T4131] Having explained how the 

return hoses could have been damaged by excessive bending, Dr Goodwin searched for an 

explanation of how some of the straight supply hoses could have been damaged resulting 

in internal creasing. As there is substantial evidence that the crew took care handling the 

hoses, Dr Goodwin thought it unlikely that mishandling was the cause of the creasing in 

the supply hoses.[T4132] Dr Goodwin examined the design of the hose coupling. 

Figure 18. Diagram by Dr Goodwin explaining potential for hose twisting caused 

by design of fitting. 

9.87 He observed that as one tightens the union nut, it tends to try to twist the hose 

tail. The friction at point ‘A’ in figure 18 is what stops the hose tail from twisting. Dr 

Goodwin estimated the torque at ‘A’ to be around 30% higher than the torque at ‘B’, so 

tightening the nut should not have the effect of twisting the hose.[T4133] 

9.88 Dr Goodwin gave evidence that friction analysis only works if both surfaces 

are in the same condition - here the hose is going into a fuel union. He explained, that if 

surface ‘A’ is wet with fuel, a type of lubricant, and surface ‘B’ is dry, then it is possible 

that the torque at ‘B’ exceeds the torque at ‘A’. As the nut is tightened, the hose tail will 

tend to rotate. Dr Goodwin stated that both ends of the hose would have the same problem 

and that this is a detail design issue rather than an assembly issue.[T4133, E401-ER032] 

166


9.89 Dr Goodwin noted that if it is essential that the hoses are not twisted in 

assembly, and a twist of 5 degrees may be sufficient to cause damage, there needs to be 

some means of holding the hoses in correct alignment while the unions are tightened, such 

as flats on the ferrules so that a second spanner can be used to prevent hose rotation.[E401- 

ER032] In Dr Goodwin’s opinion, there is no effective way to restrain the hose from 

twisting.[T4133] 

9.90 Dr Goodwin concluded that: 

General lack of design 

a. there was no provision for preventing a twist of the hose as one tightens 

the nut; and 

b. it was likely that the damaged supply hoses were damaged in twisting 

rather than bending.[T4133, E401-ER032] 

9.91 Dr Goodwin concluded that no design analysis had been carried out in relation 

to the installation of the flexible fuel hoses. Flexible fuel hoses had simply been used to 

replace fixed rigid steel lines, without any recognition that this was a design change that 

required the attention of a design engineer. Dr Goodwin stated that a design engineer 

would have taken into account the pulsation in the system. The failure to take into account 

pulsation in the system meant that the flexible fuel hoses were destined to fail eventually 

due to fatigue, however well made or fitted.[T4232] 

9.92 Dr Goodwin concluded in his report that: 

Conclusion 

There is convincing evidence that the fuel for the fire was supplied by a 

failure in fatigue of a return hose. These hoses were not fit for purpose 

because of an aspect of the requirement which was not understood by any of 

the parties involved. I would expect an examination of this change as an 

engineering design issue to have led to the consideration of the dynamic 

nature of the working pressure and therefore to an appreciation of the fatigue 

requirement.[E214] 

9.93 The hose arrangement did not conform with good engineering practice in 

various respects, as well as the failure to take into account spill pulses. 

9.94 The flexible fuel hoses were not properly designed and they were destined 

to fail. 

Design improvements to flexible fuel hose assemblies 

9.95 Since the dissemination of MSC Circ.647 in June 1994 [E462], IMO has 

prepared draft MSC Circ.861 which was approved in May 1998.[E214F] As at 17 June 

1998, it had not yet been issued. MSC Circ.861 was reviewed by the Sub-Committee on 

Ship Design and Equipment in March 1998 and was passed to the MSC unchanged. 

9.96 Draft MSC Circ. 861 states that there had been a continuing incidence of MMS 

fires due to the leakage of oil. Investigation of fire casualties, analysis of casualty statistics 

and technical research has revealed that leakages from the fuel system are due to the failure 

167


of worn, incorrectly fitted, slack, over-tightened or unsuitable components. IMO found that 

the major contributing factors to failure of fuel system components were: 

a. the frequent partial dismantling and reassembly of the system for 

maintenance purposes; 

b. the effects of high frequency, short duration pressure pulses which are 

generated by the action of the fuel injection pumps and which are 

transmitted back into the fuel supply and spill rails; and 

c. vibration. 

9.97 In relation to design consideration, draft MSC Circ. 861 states, among others: 

Recommendation 

3.1 It is essential that the fuel system is designed to accommodate the high 

pressure pulses which will be generated by the injection pumps. The engine 

manufacturer and/or the fuel installation manufacturer and the piping 

installer etc. must be consulted for an explicit statement of the fuel system 

parameters, including the maximum pressures which will be generated. 

Many engine manufacturers, aware of the potential risks due to high pressure 

pulses within the fuel system, now aim to limit the magnitude of the pulses 

to 16 bar at the engine fuel rail outlets. 

3.2 The alternative approaches which may be considered by the designer 

are: 

- design of the fuel system such that it is able to contend with the magnitude 

of pressure pulses which are generated. Piping systems should be designed 

and installed to an appropriate classification society or ISO specification; 

- installation of pressure damping devices; or 

- specification of injection pumps which are designed to eliminate or reduce 

high pressure pulses.’ 

9.98 The RAN should adopt the guidelines set out in IMO’s draft MSC Circ. 

861 in relation to diesel engine fuel systems. 

168

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