Time is money, so they say, and that's at least part of the push toward automating machines, buildings, and vehicles. Specifically, the need to fine-tune what's going on, be it a car engine, an office suite, or a production plant, requires some form of feedback from the system in question, and that's where the sensors come in.
Let's talk about maintenance for a minute. The best time to replace a part is when that part has reached the end of its useful life. If you have no way to tell when that happens, you end up replacing it based on how long it's been in operation or how many miles you've driven. That adds up to a bunch of maintenance time and cost to replace a part which may still be perfectly fine. However, replacing still good parts with new good parts is still cheaper than having an equipment failure and a bunch of unplanned and expensive downtime.
You Spin Me Right Round
There's a definite trend, especially in industrial automation, toward active condition-based monitoring in which sensor feedback from a machine alerts you to potential problems, or at the very least problems that haven't developed into really serious ones yet. Rotating machinery, in particular, is prone to all kinds of fun failure modes and there has been a slew of products released over the last couple of years to address this very problem. Condition-based monitoring allows you to perform maintenance when you need to, based on the actual health of the parts involved
And now condition-based monitoring is moving to helicopters. According to a recent article in the Huntsville Times, engineers at the Army Aviation and Missile Command (AMCOM) are developing an aviation condition-based maintenance system to help the crews maintaining the military's helicopters to streamline the process. Apparently, some helicopters can require as much as three hours of maintenance for every hour of flight time and when that maintenance has to happen in the great outdoors, regardless of ambient temperature or incoming artillery, anything that cuts down on maintenance time (while improving safety) is a Good Thing. The developers are also looking at having this maintenance sensor send its data back to the ground from the aircraft so that when the helicopter lands, the crew on the ground will already know what needs to be fixed.
I wish the folks at AMCOM every success in their endeavor; it's an elegant solution to a very real problem.