Predictive Maintenance Case Study

BY ERIC BECHHOEFER, CEO AND CHIEF ENGINEER

I’m often asked to share examples of how our Foresight HUMS can find issues before they manifest themselves and affect helicopter maintenance practices. I was onsite with a customer last week and saw a perfect example.

A customer’s aircraft, which we’ll call XV, was showing a trend in the ACC duplex bearing. We had seen this component’s Health Indicator start to trend about 50 hours before.

Our predictive HI lines (shown in purple below) indicated that the component had about 50 hours of Remaining Useful Life left.

The maintenance technician was then able to drill down and click into the Component Detail, a view that enables users to see the raw vibration monitoring data after we’ve applied our signal filtering algorithms. It was clear from this graph that this was a ball fault.

Our customer was then able to compare this bearing across the fleet and confirm that while LP’s bearing indicated it would soon need maintenance, XV had the most damaged bearing.

Since the aircraft was coming in for a 2500 hour inspection, the maintainer decided to replace the bearing proactively. This is a pretty tough bearing to get to as it requires disassembly of the main gearbox. I was at the customer site when the gearbox was pulled. The maintainer asked me – prior to pulling apart the gearbox – “Is this real?” I assured him “Yes.”  

We often hear from mechanics that so-called “legacy” or “Generation 1” HUMS generate false positives, eroding confidence that what the screen says syncs to reality. So this was a key moment for us and Foresight’s credibility was on the line.

As expected, the maintainer called the next day a very happy guy. The gearbox disassembly revealed that one of the ball elements was scuffed. He was able to see a slight fuzz on the chips detector. 

This is how GPMS creates value for operators on the ground: by helping to minimize unplanned downtime. In the event of a chips light, an immediate landing far from base can be costly and lead to extended service interruptions.

Here is XV’s bearing back to normal after the maintenance action.  

So when the question “Is this real?” comes up again, I think I know how our maintainer/customer will likely answer!