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 better pilots, we're all in this together.

Aero-Tips 06.03.06

After recent Aero-tips articles on two-bar and three-bar Visual Approach Slope Indicators, or VASIs, a couple readers wrote to say they had trouble visualizing why "red over white" is the proper visual indication when on glide path.

Look at the figure below (click on the image to see a larger version). Each VASI consists of a pair of runway-side boxes that radiate two visual glidepaths—one red, the other white.  The white beam is focused at a slightly higher angle, the red slightly lower. 

Note: For purposes of this discussion I'm describing the two-bar VASI system. A three-bar includes yet another box and another pair of radiated glidepaths.

The far box lights are actually angled slightly steeper than the optimal glide path. The nearer box lights are angled slightly shallower. (This is why you can't accurately fly a "single-bar VASI" if one or the other light boxes is inoperative).

The beams are adjusted like this so that if you're viewing from the "proper" position you'll see red from the far box -- because you're below that box's red/white dividing line, below the "high" glidepath. You'll see white from the near box because you're above the "low" glidepath. The result is "red over white", which is "right" for flying the visual approach slope to the runway.

• Position 1 (in the figure) shows approaching too low on the glidepath.
• Position 2 is the indication for "on glidepath" with this VASI.
• Position 3 indicates flying too high on the VASI glidepath.

Aero-tip of the day: Visualize why you see the expected VASI glidepath indication to fly safely to the runway.

FMI: Aero-Tips