The most important part of an aircraft engine, arguably, is the lubrication system. But it’s also the most vulnerable. Generally, lubrication systems are recirculatory. Fresh oil is introduced to the lubrication system and met withbearings, seals, and gears that wear and erode, producing abrasive contaminants. The oil flushes them away and carries them to the scavenge oil flow away from the sump where they are almost completely filtered out.
Thus, the oil can go through and be resupplied into the system. Unfortunately, because the oil has to pass through small holes and passages, even the smallest particles can block the oil flow and cause lubrication failure if it’s not properly filtered.
Normally, fresh oil will gradually dissolve contaminants and hold microscopic particles in suspension such that there is a normal level of contamination reflective of the condition of the system. Larger than normal particles can be collected by the filter, but because the filter inspection intervals are too long, these particles can have ample time to cause further damage. As a result, magnetic chip detectors are often installed in the scavenge oil flow of each sump or in the common scavenge line downstream of the pumps. Because the gears and bearings are made of steel, the magnetic chip detector can easily collect particles from 0.02 to 1 mm in size. The chip detector has to be regularly checked and maintained, and the particles can be sent to a lab for analysis.
Another tool for monitoring lubrication systems is the Spectrometric Oil Analysis Program (SOAP). As a maintenance tool that uses an emission spectrometer to check the condition of oil lubricated mechanical systems, SOAP can analyze the specific elements and concentration of particles from 0.001 to 0.02 mm in size. There’s always a certain level of normal contaminants, but periodic analysis with SOAP will show any increases in particle concentration or size, which will indicate if there is increase in wear or damage. When used with a magnetic chip detector, SOAP is a very useful tool in engine maintenance and repair.
ASAP Logistic Solutions is a premier supplier of aircraft and aviation parts owned and operated by ASAP Semiconductor. With a vast inventory of new and obsolete parts including aircraft lubrication systems, filters, and chip detectors, we can help you with all your AOG and mission-critical requirements. Visit us at www.asap-logisticsolutions.com to get started.