INSTRUMENTAL NEUTRON-ACTIVATION ANALYSIS IN SUPPORT OF IMPLEMENTATIONOF QUANTITATIVE FILTER DEBRIS ANALYSIS

Aircraft engines and transmissions are regularly monitored by several integrated techniques such as periodic analysis of the metallic wear d ebris deposited in the lubricating oil, termed Aircraft Oil Analysis ( AOA). Trending of these results indicate to the fleet manager the oper ational health of each aircraft. Instrumental neutron activation analy sis (INAA) provides similar results and for a greater range of metals than the analytical techniques used in the field laboratories. However , for new oil-lubricated systems with fine filtration, the wear debris collects on the oil filter and little debris remains in the oil for a nalysis. The wear debris must be removed from the filter and ends up a s a solid sample. Ultrasonic cleaning is used and the wear debris may be inspected qualitatively to determine the wear mechanism, termed Fil ter Debris Analysis (FDA). Quantitative analysis follows, termed Quant itative Filter Debris Analysis (QFDA) and, for techniques other than I NAA, the sample must be dissolved. A combination of three acids and mi crowave digestion are then used, Then, to use the present field techni que, this aqueous sample is then converted to an appropriate organic m atrix before analysis. Again, INAA has been used to develop and monito r this QFDA technique for field application.