According to the specifications of the manufacturer, partially or fully synthetic automotive engine oils of the 5W30 SAE class will be used to lubricate the piston engine.
As in a car engine, they must lubricate, protect against wear and corrosion, cool engines and keep them clean. A particular challenge awaits the transmission oil of piston engines. At the same time, it also supplies the hydraulic propeller governor and hence must take over the function of a gear and hydraulic oil.
Not every lubricant is suitable for aircraft. Before a given oil is authorised for use in engines or gears, it must undergo elaborate approval procedures. The test runs are carried out on engine test beds at Austro Engine GmbH. The testing plan and protocol are then submitted to the competent aviation authority, Austro Control. Together with EASA, the European Aviation Safety Agency, it issues the official approval. Only then may the oil be used in the respective aircraft.
But that is not all. Maintenance and thus naturally the oil service of an aircraft must be precisely documented in its logbook. An oil change may also only be carried out by a certified aircraft mechanic or in an authorised service workshop. Every 100 hours, the 7 litres of oil of the piston engine must be changed. After 300 flying hours, the 2 litres of transmission oil must be changed. These intervals are obligatory, pursuant to the guidelines of the engine manufacturer and the aviation authority. Austro Engine GmbH also recommends that users commission OELCHECK to investigate the used oil. As a rule, this piece of advice is followed. Ultimately, any irregularities or potential damage to engines and gears are discovered early through analyses of lubricants and safety is significantly increased. In this way, hundreds of investigation results have accrued over the years. They are all evaluated by the manufacturer of the engines, in accordance with continuous quality controls and optimisation.
From the results of the OELCHECK laboratory reports, it has nevertheless also been clearly apparent that even after 100 flying hours, the engine oil is almost always as good as new and hence absolutely effective. Empirical values are now collected and the data is then analysed with even greater precision. Austro Engine GmbH aims to draw up documentation and to request a significant extension of the oil change intervals from the aviation authority. This would significantly reduce maintenance expenses and costs for the operators of the aircraft, and this with maximum safety and boundless pleasure in flying!