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 03.25.06

Oil temperature and oil pressure are two of the most vital indicators of immediate engine health. The analogy to the body’s temperature and blood pressure is not too far off -- if one or the other is excessively high (or low), trouble may be on the way.

Engine oil temperature and pressure, however, are even more closely inter-related that your body’s “operating indications.” Oil is a fluid that becomes less or more viscous, or “slick”, as its temperature changes. Pressure and temperature, then, will vary predictably relative to one another.

Note: Modern multi-weight and partially synthetic oils are modified to provide adequate viscosity over a wide temperature range, creating year-‘round oils and those that accommodate use from the frigid mountains to the searing desert in a single flight. The dictum that the two indications work together still holds.

Inverse Proportionality

In an essentially closed system (like an airplane engine), if the engine is running when oil is cold, then oil pressure will be correspondingly high. Conversely, as oil warms the pressure should drop. Okay, maybe it’s not mathematically inversely proportional, but the term gets the idea across for our purposes.

1. In the figure Condition 1 shows typical oil temperature and pressure just after engine start. Oil is still cold (left gauge), so pressure is expected to be high (right).
2. In typical normal running (Condition 2), oil has reached its running temperature and pressure has dropped to its normal indication. These should remain steady for most of the flight.
3. Condition 3 is one possible abnormal indication. Oil temperature is rising and pressure has dropped -- for some reason (oil leak, blocked oil line, etc.) the system isn’t going to continue cooling and lubricating the engine properly. The important point is that the two indications together make sense. If you see high oil temperature with normal oil pressure, or low pressure with a normal or cool temperature, you have a discrepancy that requires close monitoring and a landing at the nearest airport with maintenance available -- but it may well be a gauge error, not a true oil problem. But if the inverse proportionality of high temp/low pressure holds true, you need to think about putting it down at the closest airport regardless of services…and be ready to land it in a field.

Aero-tip of the day: There’s logic to the combination of indications relating to a common aircraft system. Know the logic and you can accurately “gauge” the health of the system, then make decisions accordingly.

FMI: Aero-Tips