100 Planes Linked To Lean Fuel Danger
Sydney Morning Herald
Thursday December 20, 2001
More than 100 Piper Chieftain aircraft still flying in Australia could experience the same malfunction which led to the Whyalla Airlines crash that killed eight people, the Australian Transport Safety Bureau confirmed yesterday.
In its final report into the Spencer Gulf accident in May last year, the bureau said it had made a world-first discovery linking lean fuel used by some small aircraft operators to a build-up of explosive residues in the engine, causing premature ignition.
Also implicated was the use of an internal lubricant by the engine manufacturer, Textron Lycoming, which ultimately caused a fatigue crack in the left engine crankshaft and put the aircraft on its path to destruction.
The safety bureau said it had investigated 10 similar engine failures in Australia since January 2000 eight Textron Lycoming engines used in the 107 Piper Chieftains registered in Australia, and two Teledyne Continental TIO 510 engines.
The head of the bureau, Kym Bills, said recommendations had been made to the United States Federal Aviation Administration (FAA), which certifies the engines, to the engine manufacturer, and to Australia's Civil Aviation Safety Authority (CASA) to tighten fuel-management and maintenance guidelines.
``There are thousands of aircraft involved [worldwide] and it is an international piece of new evidence that hasn't been available before," Mr Bills said.
``No-one should be blamed for this tragic accident but there are important lessons to be learnt for engine manufacturers, operators, pilots and regulators to ensure it doesn't happen again."
The Whyalla Airlines double-engine failure the first recorded ditching of a Piper Chieftain in Australia happened 26 kilometres from Whyalla and just seven minutes before the plane was due to land at the South Australian town on a regular run from Adelaide.
At least two of the seven passengers drowned after impact in the May 31 crash.
No lifejackets were required on the aircraft but the bureau found it was ``highly likely" that the pilot and passengers might have survived if they had been available.
CASA said yesterday that all small aircraft flying over water would carry life jackets from early next year.
Mr Bills praised the 21-year-old pilot, Ben Mackiewicz, for his skilful landing in one-metre waves on a ``dark, cloudy and moonless night".
``The pilot would have had no option but to ditch the aircraft," he said. ``There's no way he would have made Whyalla."
Mr Mackiewicz left Adelaide at 6.23pm and advised air traffic controllers at 6.56pm that he was 35 miles south-east of Whyalla and beginning descent. He said the estimated time of arrival was 7.08pm, but at 7.01pm he sent out a mayday saying both engines had failed.
The report suggests 6.37pm just 14 minutes after take-off as a possible time of fracture in the left engine's crankshaft.
Mr Bills said the problems identified in the report seemed to be more common with high-powered piston engines used in Piper Chieftain-type aircraft, but were not restricted to the plane or its engines.
The left engine failed first due to the fatigue crack in the crankshaft, which had developed over about 50 flights.
This was caused by the combined effect of the manufacturer's use of an internal lubricant and Whyalla Airlines' practice of lean-fuel running a low fuel-to-air ratio used partly for fuel efficiency.
Lean-fuel running approved by the manufacturer and the FAA increased the likelihood of lead oxybromide deposits forming on the cylinder piston crown.
``They can then glow and, of course, ignite the fuel ahead of the normal sparkplug ignition," Mr Bills said.
The likely cause of the second engine failure was ``rapidly raised temperatures" that melted a hole in a piston, causing loss of power.
The Australian agent for Textron Lycoming, Hawker Pacific, did not return Herald calls.
The managing director of Whyalla Airlines, Chris Brougham, denied that he had skimped on fuel levels to run the airline, which was shut down after the crash.
The report found Whyalla airlines had ``deficiencies in its safety culture" and CASA was criticised for gaps in its surveillance.
The Minister for Transport, John Anderson, said CASA would urgently enact the report's recommendations.
CRACKING UP THE EVIDENCE
Crankshaft fatigue
A crack in the left engine of the Whyalla Airlines plane, traced to lead oxybromide deposits. These were caused by "lean fuel" running and the manufacturer's internal lubricant. The crack developed over about 50 flights.
* Low fuel practices `a risk' Page 5
© 2001 Sydney Morning Herald
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