"How would you handle a go-around?" This is a perfectly logical question for a pilot trained in airplanes but it's likely to be met with a quizzical, "Why would you want to?" from a glider pilot. The question simply doesn't occur to a glider pilot who has been trained to land from every approach. So, how do soaring guys and gals manage to land nicely every time? Its a matter of energy management, judgment and planning - something any skateboarder or mountain bicyclist understands.
Imagine you're flying a Cessna 172 trimmed for level flight. Now, reduce power for a 100 FPM descent and you're flying a 'virtual' sailplane in a typically flat glide. Two things are obvious - you're not coming down very fast and it would be very hard to land without reducing power a lot more.
Now, lets shift to a glider. Take note of a handle on the left side of the cockpit with a blue knob. That's the spoiler handle - think of it as an "inverse throttle". If you pull it fully aft, panels will pop out of the upper surface of each wing creating enormous drag, reducing the glide ratio from about 50:1 to about 8:1 which is about what the C172 will do at idle power. You can see where I'm going with this.
Now imagine you're in a glider on a long final approach to a VASI equipped runway with spoilers 50% deployed. The VASI glide path indicator lights show two red and two white marking a perfect glide path. As the glider continues, one white light turns red indicating you are dropping below the glidepath. To compensate, you push the spoiler lever forward to only 40%, increasing the glide ratio. The red light obediently turns white again, showing you are back on the glidepath. Pilots learn the visual appearance of a runway when on glidepath so, with experience, VASI is no longer needed.
Spoilers are simple - push forward to glide further and pull back to come down sooner. Unlike power adjustments, there's no 'spool-up' time nor any chance an engine will cough and stumble. Spoilers act instantly so if you want to land exactly there just dial it in with spoiler adjustments.
"OK", you say, "You have to get it onto the final approach - how do you do that?" Cross country glider pilots have a chance of landing in a farm field whose elevation is unknown. That means the landing pattern must be learned without reference to an altimeter or familiar landmarks. Only the landing surface itself is used as a visual reference. Basic athletic training says you go where you look.
Planing to arrive 2000' or so above the runway will let the pilot observe traffic, runway and windsock before choosing and entering the landing pattern. I prefer a "270 overhead" landing pattern with a midfield crosswind leg aiming to cross the runway at an estimated 1000' AGL.
There are two important visual angles to estimate. Turn downwind to pass abeam the intended touchdown point such that it is seen with a 30 - 45 degree "angle of depression" below the horizon. That way if the glider is high, it'll be further away or if it's low, it'll be closer - either way, the pattern works. Turn base when the same touchdown point is seen halfway between the wing tip and rudder or +or- 135 degrees relative bearing from the nose. From there make adjustment to the spoilers and/or ground path as needed to arrive on the final approach and glidepath. There's an acronym for this; TLAR for "That Looks About Right" - sounds silly but it works.
The Private Glider Pilot Practical Test Standards call for touching down beyond a named threshold and rolling to a stop within 200 feet of a designated place (like a runway intersection) To do that, just get the glider down and rolling so you can use the wheel brake which is usually engaged 75% spoiler. It's just like parking a bicycle.
If you'd like to try this with a glider flight instructor (CFI-G), go to WWW.SSA.ORG, scroll down and click on FAST which stands for "Fly a Sailplane Today". It's the best $99 deal in aviation.
Next time, what about landing in a farmer's field - FOR REAL?