the vehicle as the cause of the failures,” said Amos. “They were drawing too much power from the alternator.” The solution was to design a new pulley. “By collecting the data and analyzing the problem, we eliminated the need for large numbers of spare pulleys to be kept in inventory, which reduced logistics costs,” said Amos. Honeywell’s Health and Usage Monitoring System (HUMS) was originally developed for rotary aircraft but has since been adapted to fixed wing aircraft, ground vehicles and Navy ships, according to Chris DeLong, the company’s senior manager for technical sales. “The technology involves vibration monitoring and is based on sonar technology that came from the Navy,” he said. “We are able to recognize problems by signal processing data collected off a rattling piece of equipment.” On the original helicopter application, HUMS is able to detect out-of-balance con- Many major systems—air, land and sea—have warning systems that sense when conditions are reaching critical levels and impending is possible. More predictive systems can take that warning window out to hours before critical failure. Needless to say, the ditions and provide information to a main- failure difference could be life and death. [Photo courtesy U.S. Army] tainer on where and how to adjust the balance. “On the Chinook we found that prepositioning of spare parts. You don’t need as many spare parts it used to take three to five days to do rotor smoothing,” said on hand in forward positions. The equipment can be positioned DeLong. “With our software they are able to do it in less than a back to a central location for maintenance.” day.” In the case of the application of HUMS to Apache helicopters, On the Apache helicopter, HUMS monitors the transmission a study found that the fleet experienced 30 percent fewer aborted gear box. “It detects metal chips in the gear box, an indicator of a flights, 20 percent fewer maintenance test flights and a 5 to 10 serious problem,” said DeLong. “Typically crews get a warning on percent reduction in scheduled maintenance activities. In the case the order of minutes before a major of a fleet of 71 Chinook helicopters, outfitting the aircraft with problem might occur. With vibraHUMS avoided nearly 3,000 maintenance man hours over a twotion monitoring, we pick up signals year period. from degrading elements and give For naval vessels, predictive maintenance means that more them 20 to 50 hours of warning that maintenance can be done in port so that the ship can reduce the there is a problem.” numbers of spare parts it carries on board. “This has an impact on The same data is used to develop weight being carried and the space taken up on board, which are trends across a fleet of aircraft, vehialways critical,” said Savage. “It also means that sailors on board cles or vessels. “The system detects will be doing less maintenance work and that has an impact on anomalies that require further their training.” investigation,” said DeLong. Chris DeLong “The biggest benefit of predictive maintenance is optimized Military organizations using maintenance planning,” said Finley, “so that when a ship comes predictive maintenance can expect in we know exactly what maintenance needs to be done during concrete results to their maintenance and logistics operations. that time frame. Other benefits include reduced ownership costs, “Organizations can diagnose and treat equipment problems and maintenance costs, man hours, and increased ship and system system failures sooner and more accurately,” said Gavaletz. “The readiness.” result is a reduction in sustainment costs, less environmental “Predictive maintenance should be part of all logistics planimpact, an optimized supply chain, improved operational readining,” said Amos. “If used effectively, it reduces the costs of logisness and increased mission confidence.” tics and you get smarter about when and where maintenance and The T56 engine aboard the Air Force’s C-130 fleet, maintained inventory will be needed. It enables you to tailor inventories of with the help of StandardAero’s Optimized Maintenance tool, has spare parts to what experience suggests the real need is.” O seen average time on wing increase by 500 hours, according to Henry. “We have also seen a reduction in unscheduled removal rates,” he added. “We generally tend to see a 10 percent to 20 percent reduction in life cycle costs using predictive maintenance.” For more information, contact Editor-in-Chief Jeff McKaughan at jeffm@kmimediagroup.com or search our online archives for related stories “Predictive maintenance provides advance warning of failing at www.mlf-kmi.com. components,” said DeLong, “and allows you more flexibility for 10 | MLF 6.2
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