Hour Meter — Articles / Posts — Flaps 2 Approach

Analogue meter mounted to the lid of the Throttle Interface Module (TIM). The meter, powered by 12 volts, records whenever power travels through the 12 volt system to the module

How many times have you underestimated the use of an item, to discover that the last time you changed the oil in the lawn mower was 15 years ago!

Aircraft, boats, heavy machinery and many other items, that require regular servicing, have an hour meter to provide an accurate time that a piece of equipment, such as an engine has been operating.

A flight simulator is made from many components. Some components will last for many hundreds, if not thousands of hours use, however, other parts have inbuilt obsolescence and will eventually fail.

Failing Power Supply

Recently, I had a problem whereby the internal hub in the Throttle Interface Module (TIM) would intermittently disconnect. The cause of the problem was the fluctuating output of the 5 volt mini power supply (MeanWell RS-15-5 Volt 3 amp) that amongst other things, powers the hub.

I was perturbed by the failure as I was sure the power supply was only a few years old. However, after consulting the service booklet I maintain for the simulator, I noted the unit had been installed 5 years ago and had been operating for 2054 hours. The part had, in my opinion, well and truly provided excellent service life considering the hours it had been operational.

Hour Meter

At the onset, when I designed the framework upon which the simulator would operate, I included two hour meters that would 'tick on endlessly' whenever power was turned on to the simulator or to specific systems within the simulator.

One meter resides in the Throttle Interface Module (TIM) and records the hours of use for the interface cards, motor controllers, power supplies, relays and other components that operate the throttle and autothrottle system. A separate, but similar meter records the overall use of the simulator (the time that the simulator has been receiving power).

An hour meter is straightforward to install and can be connected directly to a 12 volt power supply (or busbar) that is always receiving power. The meter (s) can easily be mounted anywhere on the simulator, whether it be inside the center pedestal, the rear of the Main Instrument Panel (MIP), or to a standalone module.

The meters I am using are analogue, however, digital meters can also be purchased. The downside of using an analogue meter is that as each increment moves through its cycle it generates a clicking sound; depending upon the location chosen to mount the meter the clicking sound may be annoying. However, an advantage of an analogue meter is that once the hours have been recorded on the meter, the information cannot be lost; a digital meter can loose the information if, for example, the backup battery fails.

Final Call

Memory for the most part is fickle, and unless trained, most people underestimate the time that a component has been used. An hour meter connected to the simulator, enables an accurate record to be kept to how long specific parts have been operating.