Rotorcraft Lubrication Optimization through Grease Sampling and Analysis

Rotorcraft, like most machines, require periodic lubrication tasks to ensure continued safe and reliable operation. Optimal lubrication intervals are desired to maintain system performance while minimizing aircraft downtime and maintenance labor. Boeing and AMRRI conducted a Lubrication Optimization Study (LOS) on the H-47 Chinook helicopter to establish the necessary engineering artifacts to define the grease lubrication intervals for selected Drive, Rotor, and Landing Gear components. Grease samples were collected from these components by H-47 operators from multiple nations and submitted for a laboratory analysis to characterize how wear, properties and contaminants change as time and aircraft hours accumulate. The LOS also revealed opportunities to further evaluate and leverage the data produced in this study, including determining superior performance of specific lubricants within the Mil-Spec designation, testing of greases for compatibility5 when mixed, and enhancing new grease cleanliness to extend component life.