ENGINE USAGE MONITORING IN THE U.S. ARMY LEAD THE FLEET PROGRAM

The U.S. Army Lead the Fleet (LTF) program rapidly accumulates flight hours on six dedicated U.S. Army helicopters to identify safety, reliability, availability, and maintainability (RAM) issues before they would occur during normal field operational usage. LTF currently consists of one helicopter of each of the following mission design series: UH-60A and UH-60L BLACK HAWK, CH-47D and CH-47F Chinook, AH-64A Apache, and AH-64D Longbow Apache. LTF aircraft provide operational usage information to correlate with discrepancies and establish meaningful usage-related safety and RAM trends. LTF aircraft usage intensity is determined by monitoring the amount of time each fatigue life limited dynamic component spends in damaging flight regimes and comparing the resultant LTF fatigue damage accumulation with the original design fatigue damage accumulation. A normalized damage index, that represents LTF usage intensity, is derived to assess usage related maintenance actions and flight incidents. Engine usage monitoring is in the planning stages and will consist of comparing LTF engine duty cycles with the original design duty cycles to determine the intensity of LTF engine life-limited component usage.