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 02.03.06

In Aero-Tips 1/8/06 we learned that the peak, or highest Exhaust Gas Temperature (EGT) is the benchmark for all mixture leaning. But how can we use this information?

Cylinder Head Temperature

Cylinder Head Temperature (CHT) is probably the most critical aircraft engine indication for engine longevity (oil temperature and pressure are more important for short-term engine health). Like other parameters, CHT follows a temperature curve relative to the EGT indication. Specifically, from a very rich mixture setting CHT increases as mixture is leaned, hitting peak CHT at about the point where EGT is 40°F rich of its own peak. Perhaps more clearly:

1. Carefully lean to find peak EGT.
2. Note the indicated temperature (as we’ve said before, the actual temperature isn’t important; we’re discussing temperature relative to peak).
3. Enrichen the mixture (add fuel) until the EGT is 40°F cooler than it was at peak.

You’re now at the maximum CHT for the power setting you’ve chosen.

There is NO advantage to running at peak CHT. If a cylinder is capable of running so hot that it wears excessively, this is the mixture setting that does the most HARM. The CHT curve is fairly flat near its peak, meaning that too-hot CHTs may result from leaning near this peak point—including the 25°F rich-of-peak EGT setting virtually all Pilots Operating Handbooks recommend. To avoid this potentially damaging (at least at high power settings) CHT range, lean either much richer or much leaner than the 40°F EGT point…whatever it takes to keep CHTs under control.

We’ll continue to investigate engine temperature management in future Aero-Tips. For more information now, see www.advancedpilot.com.

Aero-tip of the day: Know what effect mixture settings have on CHT, and manage your engine to avoid excessive cylinder heat.

FMI: Aero-Tips