In aviation you have Preventative Maintenance, and you also have Routine Maintenance.
Routine Maintenance includes tasks such as lubrication, minor inspections, checking oil, or even chain tensions, whereas Preventative Maintenance is performed when the aircraft is down, and requires more intrusive maintenance. In my opinion, I don't consider greasing and oiling chains as preventative. Preventative maintenance on an aircraft, one takes apart a component from a system (ex: air conditioning clutch) and it is inspected for bad bearings, corrosion, or anything else that exceeds the manufacturer's specifications. Nearly 90% of the time, everything looks good, but it's that 10% of the time you find something worn that needs to be replaced. Ideally, this is something you want to find when the line is down, and not when you are in full production. This is also a good opportunity to clean hard to access areas.
If you are a supervisor or manager, I would highly recommend performing these maintenance sessions once per year, once on each piece of equipment. Basically this would be like taking it apart, then putting it back together again, while looking for anomalies. The benefits includes finding snags, and is a very good opportunity for your maintenance staff to become extremely familiar with the equipment that they are using, quickly. Additionally, I would recommend that they use as much manufacturer literature as possible, including exploded view diagrams, and maintenance procedures.
[Every small aircraft must, once every year, undergo an annual inspection. This entails the complete inspection of aircraft for security, operation of systems for correctness, and servicing of all aircraft components. Typically, the time investment for an annual inspection ranges from six to eight hours...]
This is one of the reasons aircraft almost never break down. Can you recall the last time your equipment failed?