PAUL PHELAN / CAIRNS
The fatal crash of a Piper Chieftain in Spencer Gulf near Whyalla, South Australia, in May 2000 is being linked by Australia's airworthiness body to a series of engine bearing failures. Seven passengers and the pilot died when the Whyalla Airlines aircraft ditched in the sea at night following a double engine failure.
Australian Transportation Safety Board (ATSB) accident investigation executive director Kym Bills says: "Based on careful analysis of the engine failures and data, it is likely that the left engine failed first as a result of a fatigue crack in the crankshaft."
The ATSB estimates that the process began about 50 flights before the accident, due to the breakdown of a connecting-rod bearing insert.
The board says that an "anti-galling" lubricating compound used during engine assembly by the manufacturer contributed to lowered bearing insert retention forces which, when combined with the effects of high combustion gas pressures developed as a result of deposit-induced pre-ignition, led to this breakdown.
A detailed independent analysis confirms that the damage to the left engine is the same delamination that has characterised failures of Textron Lycoming TIO-540-AE2A engines also used on the Piper Malibu Mirage and Cessna 206. California's highway patrol has grounded its fleet of new Cessna T206Hs as a result. The accident has also triggered a class action by Malibu Mirage owners against Textron Lycoming and New Piper, new owner of the Chieftain design rights.
Source: Flight International
