4. LESSON 11 - APPROACH
Key points:
- Assess the position of your reference point and control it with airbrake
- Coordinate stick with airbrake to control speed
- Half to 2/3 airbrake is ideal
After making your final turn at the end of the circuit you roll out to fly the approach towards your reference point. Every glider has a minimum approach speed and we need to add extra if it’s windy. Your instructor will guide you on this. Make sure you are flying at the approach speed needed for the day, and keep this airspeed constant throughout the approach, until the round-out. The rate of descent, or how steep your glide path is, is controlled using the airbrakes.
A good approach path is quite steep, needing half to two-thirds airbrake. To begin with, your instructor may handle the airbrakes for you, while you get used to holding a constant airspeed and direction as the ground gets closer and closer. Varying the amount of airbrake while keeping the airspeed constant was covered in Lesson 4.9. The airbrakes provide a huge amount of flexibility, allowing us, once practiced, to place the landing very precisely.
If your glide path is straight towards the reference point then this will stay in a constant position in your canopy. If you are undershooting the reference point, it will appear to move up the canopy. If you are over- shooting, it will go down the canopy, to disappear under you. As you fly down the approach you are continually assessing whether you are under- shooting or overshooting. If you are undershooting you need less airbrake and if overshooting you need more. At the same time you must keep the airspeed constant, so your gaze flicks between the two: airspeed and reference point.
IDEAL APPROACH
Here is a description of the ideal approach you are aiming at. After turning onto your final approach, check your airspeed and make sure you are tracking straight towards the reference point. Then you fly forward until you intercept the approach path for half to two-thirds airbrake, open this much airbrake (i.e. quite a lot) and continue down a steady approach to the round-out, just above the reference point.
Note that the lower or further back your final turn, the further forward you must fly before reaching the optimum half to two-thirds line. Note also that as you approach this line, with no airbrake, you will start to see an overshoot. If you do not see an overshoot then opening the airbrakes will produce an undershoot. Your aim is to judge when the amount of overshoot you are seeing is just right, i.e. when opening half to two-thirds airbrake will put you on a steady path straight to your reference point. Opening a small amount of airbrake too soon (and hence coming down too flat an approach) is a common fault. Remember that you don’t want to open them until you can use plenty.
If you find that you have opened the airbrakes too soon (you see an undershoot after opening them) then it’s best to close them and fly forward for another go at finding the optimum line. Beware of closing them just a bit, and then another bit, until you end up with too little airbrake, which means no margin of error if you fly through sink, plus a more difficult round-out. Don’t keep adjusting the airbrakes as you get close to the ground. Keep the brakes steady once you’re getting near to your round-out height (see Lesson 4.18). It is possible to finesse a landing by varying the airbrakes during the round-out (you might see your instructor doing this when he or she is taking over from you while you are trying to get the hang of landing) but while you’re learning it’s important that you keep them constant.
SUMMARY
- Judge when you are on the optimum approach line and pull plenty (half to two-thirds) of airbrake
- If undershooting, close the brakes and return to step 1.
- When you’re getting close to round-out height, keep the brake setting constant.
- Keep the airspeed constant throughout.
Crosswinds and strong winds are covered in the following lessons.
