Glider getting low
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zero sink when to quit radio low lift

Editor: In Part I, Roy began a discussion with Strategies When You Are Low. Thermalling low can be dangerous. These two articles are focused on mitigating risk and increasing your chances of climbing away from a safe altitude. Follow along as we continue to get lower...

Accept you are in survival mode

If you are carrying water ballast, dump it all, right now.  You need the glider light and maneuverable. You must be able to climb and exploit any lift that you find, and you will need the extra margin that being light gives you over the stall speed - especially in the tight turns needed in small thermals close to the ground. The small advantage that ballast “might” give you later (if you save the flight) is not worth the trouble that the ballast causes when thermalling down low. And if your search strategy doesn’t work, you want the machine as light as possible when you land in a farm field.

Work any lift you find - no matter how weak

A low save is not the time to be choosy about the strength of a thermal or to slavishly stick to some McCready setting. You are buying survival time. Waste nothing.  Work any thermal that you find - no matter how weak. This gives you time and opportunity to look around and see other resources like birds circling, other gliders climbing, smoke starting to go vertical, dust devils forming, and other signs of a thermal working up from the ground.  Do not leave a weak thermal until you are certain that the next step will be better than what you have now.  Sure, you will be slow - but you will be even slower sitting on the ground.

When critically low, never leave zero sink

“Zero sink” is a thermal that matches the sink rate of the circling glider and, if you use it well and perfectly, you will climb.  If the day has otherwise been good, zero sink is either the beginning of a thermal (which is wonderful) or the end of a thermal - which still gives you some time to think and sort things out.  Either way, you should stay with it until it’s gone, or you see an alternative that you are sure is better.

Focus your mind on here and now

This is the time that you must fly smoothly and excellently. There is nothing else important to think about. Forget the mistakes that you made getting here and forget how late it will be if you get back. Ignore what your buddies or the other competitors are doing. Your universe is only THIS THERMAL, RIGHT HERE, RIGHT NOW, and you must work it smoothly and perfectly. Move your circle smoothly to first establish a positive rate of climb for the full 360 degrees of each circle, That’s a huge first step.  Adjust the bank to maximize the climb rate. Remember that thermals are smaller down low, and you will need more bank. Also, remember that increasing the climb from a mere .5 kt to 1 kt cuts your climbing time in half.   When you have the thermal centered and have maximized the climb, keep trying to make it even better, and don’t relax until you get to a more comfortable altitude. 

The radio is a distraction you don’t need

If your landing target is an airport, you should have already tuned to the local frequency when you arrived in the area and all you need to make is a simple crisp position report like, “Hometown traffic you have a glider maneuvering one-mile northwest of the airfield at 1100 feet”. That’s all that is needed.   If you are working a weak thermal and get a radio call from another glider, your response should be only a curt, “Sorry, busy now”, and nothing more. There will be time for talking later.

Get your head out of the glider

This is probably the most important thing. Use the audio vario with only brief glances at the instruments. Focus on what is happening outside. Look for birds, dust devils, smoke rising straight up, and other gliders. On the ground try to visualize what will get warm and stay warm. Look for vertical structures that will focus or trip thermals. Moving cars, trucks, and trains will kick off thermals as will airplanes on the runway and moving machinery in a farm field. Sandpits and rock quarries hold heat well.  And don’t forget to look straight up - frequently you will see a building cloud that wasn't there when you started the climb, or a bird, or another glider.

Know when to quit 

This is discussed in the introductory note and is of fundamental importance. The lower you attempt to thermal - the higher the risk you are taking. Wind and gusty conditions greatly increase your risks while they diminish the likelihood of success (because they chop up the thermals down low). Decide in advance what your limits are for today and stick to them. Commit to a safe organized approach, lower the gear, and execute that plan. Sometimes it is helpful to think about why you got low on this flight. If it was just bad luck and the air is still alive, and the flight salvageable - that may be a consideration.  But if it is late in the day with the sun angle low or a building overcast causing the ground to cool off - are you just postponing the inevitable?  And taking risks to do that?  This is my 50th season flying gliders and while I have made thousands of flying mistakes that I would do over differently, none of them were the decisions to end a flight and land safely.

I hope that these ideas and strategies may help you to avoid a land out.  They have helped me, at least sometimes. But even if they don't work, you will step out of the glider knowing that you did your best, that you had a strategy, and that you executed that strategy.  That’s something that takes away the sting of the land out and gives you confidence for the next flight.

Stay safe. Have fun.  Get better.
 Roy Bourgeois

Roy Bourgeois  Roy Bourgeois is a well-known US and South African glider pilot who served many years as the Chief Pilot for the Greater Boston Soaring Club and now lives and flies in Arizona. He has held several US national records, competed in many US and Canadian Nationals, and has flown over 300,000 XC kilometers in his 4400 hours of gliding. He can be reached at [email protected]