Oil diagnostics of piston aircraft engines

history of oil analysis in aviation

History shows that one of the flywheels of the development of technology and innovation are times of increased investment in the military development of countries. Therefore, the first half of the 20th century, was a period of intensified progress in diagnostic methods and techniques. A key one appears to be a program created by the U.S. Joint Army, Navy and Air Force called JOAP (Joint Olive Analysis Program). This program was designed to standardize in the field of lubricant testing and is, by the US Army, still used, in an updated form, today.

spectrographic examination of oil

Military standards often enter general use. Not surprisingly, over time, oil testing has become a standard in the technical evaluation of jet engines, piston engines or hydraulic systems in civil aviation, including in Poland. Since 29.08.2016, in accordance with Guideline No. 9 of the President of the ULC, spectrographic (elemental) testing is recommended during each planned oil change.

certified laboratory and diagnosticians

The amount of lubricant needed for laboratory analysis is only 50 ml. The correct way to take a sample is presented in numerous documents or guidelines from engine manufacturers, e.g. Textron Lycoming Service Letter No. L171 czy Continental Aircraft Engine Standard Maintenance Practice Manual. The oil test is performed using the ICP (Inductively Coupled Plasma) technique according to the American ASTM D5185 standard, in an ISO 17025-accredited laboratory. The results obtained, should be evaluated by experienced specialists, especially in a situation where only some engine manufacturers provide limits as to individual elements.

STLE (Society of Tribologists and Lubrication Engineers) or ICML (International Council for Machinery Lubrication), are organizations that bring together the world’s top lubricant performance evaluation specialists. When ordering tests, it is a good idea to make sure that the laboratory is certified as a member of the above-mentioned associations. This ensures that the results obtained are reliable and reliably assessed.

laboratory report

The result of testing a sample is a laboratory report, which should include the results of the current analysis, as well as several historical (previous) tests, so that the trend of changing elemental concentrations depending on the hours of the raid can be observed. A correct report must be accompanied by a diagnostician’s commentary – in the absence of manufacturer’s guidelines, the diagnostician will evaluate the results and recommend possible corrective actions. The diagnostician also answers questions and concerns that may arise after the test. Through the evaluation of qualified specialists in the field of oil analysis, the user (CAMO) will be able to make an informed decision on the continued operation of the machine.

oil testing – greater flight safety

Oil testing is a helpful instrument in the maintenance process of aircraft engines. They provide important information about consumption processes and allow you to decide on possible service based on analytical data. It is worth remembering that knowledge from oil research is also used in the context of flight safety.