An Inquest taken on behalf of our Sovereign Lady the Queen at Adelaide in the State of South Australia, and Ada, Oklahoma and New York City, New York in the United States of America, on the 22^nd July to 5^th August 2002, the 26^th August to 3^rd October 2002, the 23^rd to 30^th October 2002, the 11^th November to 24^th December 2002, the 3^rd, 29^th and 30^th days of January 2003, the 14^th and 28^th days of February 2003 and the 24^th day of July 2003, before Wayne Cromwell Chivell, a Coroner for the said State, concerning the deaths of Benjamin Kurt Mackiewicz, Joan Elizabeth Gibbons, Teresa Viola Pawlik, Wendy Ruth Olsen, Peter Desmond Olsen, Neil Marshall, Richard Deegan and the disappearance of Christopher James Schuppan.

• Benjamin Kurt Mackiewicz, aged 21 years, late of 2/18 Kent Road, Keswick, died in Spencer Gulf in the State of South Australia on the 31^st day of May, 2000. I find that the cause of death was salt water drowning;

• Joan Elizabeth Gibbons, aged 66 years, late of 13 Lee Street, Whyalla, died in Spencer Gulf in the State of South Australia on the 31^st day of May, 2000. I find that the cause of death was multiple injuries including flail chest;

• Teresa Viola Pawlik, aged 55 years, late of 42 Wainwright Street, Whyalla, died in Spencer Gulf in the State of South Australia on the 31^st day of May, 2000. I find that the cause of death was salt water drowning;

• Wendy Ruth Olsen, aged 43 years, late of Mangalo, Cleve, died in Spencer Gulf in the State of South Australia on the 31^st day of May, 2000. I find that the cause of death was salt water drowning;

• Peter Desmond Olsen, aged 45 years, late of Mangalo, Cleve, died in Spencer Gulf in the State of South Australia on the 31^st day of May, 2000. I find that the cause of death was salt water drowning;

• Neil Marshall, aged 56 years, late of 2 Herbert Street, Newton, New South Wales, died in Spencer Gulf in the State of South Australia on the 31^st day of May, 2000. I find that the cause of death was salt water drowning;

• Richard Deegan, aged 44 years, late of 16 Montrose Street, Netherby, died in Spencer Gulf in the State of South Australia on the 31^st day of May, 2000. I find that the cause of death was salt water drowning;

• Christopher James Schuppan, aged 39 years, late of 8 Mildred Street, Whyalla Stuart, died in Spencer Gulf in the State of South Australia on the 31^st day of May, 2000. The cause of death has not been determined.

At 7:01:14pm on Wednesday 31 May 2000, a Mayday call was received at Adelaide Flight Information Service. The call came from Mr Ben Mackiewicz, the pilot of a Piper Navajo Chieftain Aircraft, registration number VH-MZK, owned by Whyalla Airlines. The aircraft was in the course of Flight 904 from Adelaide to Whyalla, South Australia, with eight persons on board. Mr Mackiewicz advised that they were ‘about one five miles off the coast of Whyalla on the Gibon-Whyalla track’. The last radio transmission from MZK was at 7:04:20pm. At about 7:06pm, the crew of another aircraft heard a signal from an Emergency Locator Transmitter which lasted for about 20 seconds.

A very substantial search and rescue effort commenced under the supervision of Australian Search and Rescue, with South Australia Police coordinating the surface search. A large number of aircraft, marine vessels and land-based vehicles were utilised during the search, including large numbers of volunteers. All searched tirelessly throughout the night.

At 12:41am, the body of Mrs Wendy Olsen was found floating in the water, and the body of her husband, Mr Peter Olsen, was found nearby at 12:51am. A third body, which I find was that of Mr Christopher Schuppan, was seen at around the same time, but it disappeared from view, and has never been recovered.

MZK was eventually located on Monday 5 June 2000, lying on the sea bed. The bodies of Mr Ben Mackiewicz, Mrs Joan Gibbons, Mrs Teresa Pawlik, Mr Neil Marshall and Mr Richard Deegan were recovered from the wreckage. Post mortem examinations established that Mr Mackiewicz, Mr Olsen, Mrs Olsen, Mrs Pawlik, Mr Marshall and Mr Deegan all died as a result of salt water drowning. Mrs Gibbons died as a result of ‘multiple injuries including flail chest’. I have not been able to determine the precise cause of Mr Schuppan’s death.

The substantial damage suffered by MZK when it impacted the water, the sudden inrush of cold water at high velocity, the sudden loss of visibility, the injuries suffered by some of the passengers, and the gasp reflex phenomenon known as ‘cold shock’ leading to aspiration of water or laryngeal spasm, would have collectively led to instant incapacitation and rapid drowning. It is very unlikely that any of the occupants of MZK, including Mr and Mrs Olsen and Mr Schuppan, survived the impact.

On the basis that none of those on board MZK survived the impact, it was not necessary to assess the quality of the search and rescue operation except in the sense that it forms part of the surrounding circumstances. However, the evidence establishes that the operation was conducted with a high degree of professionalism and skill, and those involved should be commended for their efforts.

An examination of the wreckage by the Australian Transport Safety Bureau (ATSB) established that the left engine of MZK had suffered a total fracture of the crankshaft, and the right engine had suffered a holed No.6 piston due to melting of the piston material.

The final ATSB report, published on 19 December 2001, attributed the fractured crankshaft in the left engine to fatigue, initiated by thermal cracking due to failure of the No.6 connecting rod bearing insert causing rubbing on the journal surface of the crankshaft. This failure was attributed to ‘high bearing loads created by lead oxybromide deposit-induced preignition’, and ‘lowered bearing insert retention forces associated with the inclusion of an anti-galling compound between the bearing inserts and the bearings’.

The ATSB postulated that the bearings in the left engine began failing much earlier than 31 May 2000, so that at a time approximately 50 flights before that, thermal cracks began forming on the journal surface of the crankshaft, creating a weakness which led to the initiation of a fatigue crack which ‘grew’ over the next 50 flights, and eventually fractured the crankshaft completely at around 1837 or 1838 during Flight 904. It was suggested that the two pieces of the crankshaft remained ‘dogged’ together, allowing the engine to continue running until 1847:15 when the two sections parted and the engine ceased functioning.

The failure of the right engine was caused by a holed No.6 piston due to melting of the piston material. The ATSB postulated that when the left engine stopped at 1847:15, Mr Mackiewicz increased the engine power settings on the right engine to an inappropriate extent (‘overboosting the engine’) until, at about 1858 to 1900, detonation holed the piston and the right engine also failed.

To that extent, the ATSB argued that the two engine failures were ‘dependent’ in the sense that the failure of the left engine was causally linked to the failure of the right engine.

Evidence of material defects in crankshafts in Textron Lycoming engines, the type fitted to MZK, did not begin emerging until a Special Advisory Bulletin was issued on 9 November 2000, although similar failures had been noted in Teledyne Continental engines, the brand fitted to Cessna aircraft among others, as early as April 2000. The Civil Aviation Safety Authority (CASA) was advised that no Australian aircraft were affected by the 9 November 2000 Special Advisory Bulletin. On 1 February 2002, Textron Lycoming recalled about 400 engines, including one fitted to an identical aircraft to MZK, at around the same time the left engine was fitted to MZK. More extensive recalls were made on 16 August 2002 and 16 September 2002. Included among the approximately 3,000 engines on the 16 September 2002 list was the left engine in MZK. Each of these recalls was accompanied by a Mandatory Service Bulletin issued by Textron Lycoming which stated that the cause of the crankshaft failures was ‘material related’.

On 14 December 2001, only five days before the ATSB final report was published, the right engine in an aircraft identical to MZK failed. Upon inspection of the engine, it was established that the crankshaft had fractured, and the appearance of the fracture was strikingly similar to that of MZK’s left engine crankshaft. The ATSB did not examine the fracture in detail, so the aircraft owner commissioned an examination by an engineer who concluded that the failure was caused by a material flaw, and not by thermal cracking.

A scientific investigation conducted for this inquiry has thrown doubt on a number of ATSB conclusions:

• Professor King, an expert in chemical engineering and Dr Zockel, an expert in mechanical engineering, both agreed with the ATSB that the damage to the right engine was due to end gas detonation;

• Professor King concluded that there was considerable doubt about the ATSB conclusion that lead oxybromides were present in sufficient quantity to be a significant factor in the failure of the left engine;

• Dr Zockel concluded that the damage to the left crankshaft was not caused during the combustion stroke of the engine and so abnormal combustion was irrelevant anyway;

• Dr Zockel also concluded that the failure of the left crankshaft was not caused by bearing failure or thermal cracking as suggested by the ATSB;

• Dr Powell and Mr McLean, both experts in metallurgy, found iron oxide inclusions at the nearby No.5 journal of the left crankshaft of sufficient size to constitute a material defect capable of affecting the tensile and torsional strength of the crankshaft. Although similar inclusions were not found at the fracture site, they could have been lost during the fracture process;

• Mr Braly, an aeronautical engineer, aviator and manufacturer of aircraft components, also disputed that lead oxybromides were relevant to the failure of MZK’s left engine, that the crankshaft could have remained ‘dogged’ as the ATSB suggested, that the aircraft could have maintained 167 knots groundspeed on one engine after 1847:15, and hence that the left engine failed first. He argued that the right engine suffered a partial loss of power at 1847:15, and that it was not until after 1858 or so that the left engine failed;

• Mr Braly also said that the mixture settings adopted by Whyalla Airlines for the climb phase of flight were too lean, and these settings may have caused or exacerbated the damage to the right engine;

• Mr Hood, a metallurgist with McSwain Engineering Inc. in the United States of America also confirmed that the left engine crankshaft in MZK did not fail due to thermal cracking initiated fatigue fracture, that bearing failure was not relevant, and that the crankshaft failure was due to a ‘manufacturing-related material condition’. Like Dr Powell and Mr McLean, they were unable to identify an inclusion in the metal at the fracture site, but he found a ‘pocket’ there, from where an inclusion may have fallen during the fracture process.

On the basis of the evidence presented at the inquest, I reached the following conclusions about how this tragedy occurred:

• It is possible (but not capable of proof) that the No.6 piston in the right engine of MZK was damaged during the takeoff and climb of Flight 904. It is very unlikely that damage occurred during the cruise phase;

• The right engine began running roughly and showing signs of end gas detonation damage at around 1837:41. Mr Mackiewicz reduced power on that engine at 1847:15 to protect it, causing a yaw to the right and reduction in groundspeed to 167 knots. He increased the RPM on the left engine to 2,400 to compensate. This was not ‘overboosting’ the engine;

• The crankshaft in the left engine failed at 1858:30 causing immediate cessation of function;

• Mr Mackiewicz may have tried to increase power on the right engine again after the left engine failed completely, but this would have not produced enough power to maintain altitude;

• The cause of the fracture of the left crankshaft was a fatigue crack, initiated from a subsurface defect in the steel as a result of a flaw in the manufacturing process, which created a point of weakness from which fatigue cracking radiated outwards over the ensuing 50 to 70 flights until it finally fractured through at around 1858:30 on 31 May 2000 causing immediate cessation of functioning;

• The cause of the failure of the right engine was end gas detonation damage to the No.6 piston, not due to ‘overboosting’ but possibly due to detonation during the ‘climb’ phase of Flight 904 when the mixture settings (specified in the Whyalla Airlines Operations Manual) were unduly lean and were likely to create unduly high peak cylinder pressures.

In forming those conclusions, a number of issues were identified at the inquest and considered. They assisted me to reach these conclusions in the following way:

• It is very unlikely that MZK would have been capable of maintaining a groundspeed of 167 knots in those conditions after 1847:15 if, as the ATSB argued, one engine was completely inoperative;

• Even if the aircraft was so capable, to achieve that groundspeed in those conditions, would have required absolutely maximum power on one engine, which was completely unnecessary since the aircraft was quite capable of maintaining altitude at a lower groundspeed on one engine at lower power settings, without putting the engine at risk;

• If Mr Mackiewicz had overboosted the engine, it is more likely that it would have been operating at 2,575 RPM (maximum) rather than 2,400 RPM detected by the ATSB;

• It is very unlikely that Mr Mackiewicz would have commenced his descent into Whyalla at 1855:54, and advised Adelaide Flight Information Service that he was expecting to arrive on time, if he was operating on only one engine at absolutely maximum power and was worried about maintaining altitude;

• Mr Mackiewicz made a number of radio transmissions after 1847:15, and as late as 1856:03 he was reporting his position without apparent concern. It is almost inconceivable that he would not have issued a Pan (distress) call at that point if he had completely lost one engine and was worried about maintaining altitude;

• It is highly unlikely that the bearings in the left engine failed long before 31 May 2000, to the extent that they could cause thermal cracks in the crankshaft and initiate the fatigue fracture 50 to 70 flights before Flight 904, and yet no sign of bearing damage, particularly metal particles in the oil, was noted in any of the services performed on the engine in the meantime;

• I have been informed that there have been a total of more than fifteen crankshaft failures in Textron Lycoming engines since this incident. Information about many of them is meagre, but a material defect has been confirmed by the United States authorities in seven cases, and suspected as the cause in the rest. This is the only case in which a different explanation for the crankshaft failure has been offered.

On the basis of these findings, I have made recommendations pursuant to section 25(2) of the Coroners Act, 1975, in the following areas:

• Pilot Operating Handbooks and Operators Manuals.

• International communication between regulators.

• On-Board Recorders.

• Self-deploying Emergency Locator Transmitters.

• Lifejackets.

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