Aero-Tips!

A good pilot is always learning -- how many times have you heard this old standard throughout your flying career? There is no truer statement in all of flying (well, with the possible exception of "there are no old, bold pilots.") It's part of what makes aviation so exciting for all of us... just when you think you've seen it all, along comes a scenario you've never imagined.

Aero-News has called upon the expertise of Thomas P. Turner, master CFI and all-around-good-guy, to bring our readers -- and us -- daily tips to improve our skills as aviators, and as representatives of the flying community. Some of them, you may have heard before... but for each of us, there will also be something we might never have considered before, or something that didn't "stick" the way it should have the first time we memorized it for the practical test.

It is our unabashed goal that "Aero-Tips" will help our readers become better, safer pilots -- as well as introducing our ground-bound readers to the concepts and principles that keep those strange aluminum-and-composite contraptions in the air... and allow them to soar magnificently through it.

Look for our daily Aero-Tips segments, coming each day to you through the Aero-News Network. Suggestions for future Aero-Tips are always welcome, as are additions or discussion of each day's tips. Remember... when it comes to being good pilots, we're all in this together.

Aero-Tips 02.15.06

To better understand the operation of typical lightplane electrical systems, we’ve been comparing the flow of electricity to that of water -- from a tank (battery) through spigots (switches) and pipes (busses) to the ground, and then propelled by a pump (alternator/generator) back into the tank (battery). Since we use electricity at different rates throughout a flight, we need something to regulate the output of our alternator "pump."

Please note: This visualization is not technically correct -- but it does a superb job of helping pilots comprehend what’s going on with the electrical system to accurately monitor it and troubleshoot problems. Engineers, mechanics and purists, please forgive this teaching tool.

Back to our water model: Let’s put a float in the water tank. When the tank is filled the float rests in an equilibrium position. So long as the pump is refilling the tank at the same rate at which water is being used, the float stays in place.

Turn on extra equipment and the flow rate increases. Water level begins to go down in the tank, taking the float with it. Conversely, turn off some loads, less water flows from the tank, and it begins to overfill -- the float rises. If we could tie the float to a cable that adjusts pump output, we could automatically adjust the pump to match the rate of water flow. If the float begins to drop, this speeds up the pump to run that equipment and enough extra to get the float back to the "full" line. Once there, the pump scales back to match this new rate of flow. If the float rises the cable slows pump output enough to get the float back to the "full" line, before again matching flow rate.

This float-and-cable adjustment to pump output is analogous to your electrical system’s voltage regulator.

Aero-tip of the day: It may be helpful to visualize electricity as the flow of water to better understand its function. We’ll look at electrical gauges and indicating systems in tomorrow’s Aero-Tips.

FMI: Aero-Tips