Low Saves
HOW LOW IS TOO LOW
Many flights have come to a bad end because the pilot attempted to climb away from an impossible low altitude. Consequently, an in-depth discussion on the subject is prudent.
At contest, we are often enthralled by spellbinding accounts of heroic saves from 97 feet. However, it should be mentioned that some glider pilots have been known, on rare occasions, to stray ever so slightly from the perpendicular truth when relaying their aeronautical adventures. Also, there is an amazing illusion which mysteriously comes into play in these situations, which is this, 400 feet actually looks exactly like 97 feet.
In discussions on the subject of off-airport landings we often neglect to mention that the optimum course of action when faced with a field landing is, not to land; if there is a possibility to safely continue the flight, it makes sense to give it a try. Naturally, there will come a time when all efforts to continue the flight must be abandoned so as not to compromise a safe landing, and that's the big question, when must we commit to land?
Pundits are often asked, "How low is it safe to thermal?" This question hardly ever brings forth a definite response. Most often the question will be evaded entirely. The reason this question fails to bring forth a nice firm, quantitative answer which you can neatly tuck away and have handy when needed, is that there isn't one. The altitude at which the decision should be made to discontinue a flight depends on several factors such as, experience, level of skill, currency, familiarity with the sailplane, and weather conditions.
EXTRA AIRSPEED AND WELL-BANKED TURNS
Low level thermalling should always be performed using well-banked turns with an additional 5 to 10 kts of airspeed. One of the most often causes of stall and spin accidents are circling close to the ground in shallow-banked turns near stalling speed.
In a sailplane, it is far easier to stall and spin from a shallow turn than from a well banked one. In turns of more than 35 degrees of bank, due to the higher stalling speed, the control response remains firm and crisp until the last moment before the stall, and recovery can be made instantaneously without any loss of altitude by simply relaxing the backward pressure on the stick. In straight flight or a shallow-banked turn, the stalling speed is lower and control response get sluggish when approaching the stall. Should a stall occur, greater control input is required and recovery cannot be made without some loss of altitude.
The good news is that using well banked turns is no disadvantage as thermals at lower levels tend to be small, and steep turns are necessary in order to climb. Extra airspeed, also improves the climb as it enhances maneuverability which helps in dealing with low level, disorganized thermals. What's more, when making that first turn in what you think is a thermal and you are concerned about losing too much altitude if it doesn't work out, a 45° bank will get you around with minimal loss of height.
EXPERIENCE AND INSTRUMENTATION
One prerequisite which has to be met before attempting to thermal at low levels is that you must be capable of flying the sailplane with only occasional glances at the instrument panel as 99% of your attention has to be directed elsewhere. Consequently, any attempt to thermal will be severely impaired if your glider is not equipped with an audio variometer.
Although you may have acquired the level of proficiency outlined above, if you get down to 800 ft on any of your first few cross countries by all means abandon the flight and concentrate on the pattern and landing. Those first off-airport landings will tax your capabilities without further challenges. Do not attempt to thermal below 800 ft until you have a handful of field landings under your belt and begin to feel a little more comfortable in those situations. That is, shear terror has been replaced by just a normal state of panic.
CURRENCY
You made good progress last year and reached new levels of performance; now it is spring and you are all primed to continue where you left off, but it has been six months since you flew last. Not being current is somewhat like being slightly intoxicated. You won't notice the effect till you get in a tight situation, as for example when trying to latch onto a couple of lumps of lift at minimum height over the boonies. So watch out, do not get too aggressive right-off, at the start of the season.
FAMILIARITY WITH THE SAILPLANE
Regardless of the level of experience you may have, if you are flying a type of glider which is unfamiliar to you it is a good idea to fly more conservatively until you get thoroughly acquainted with the glider.
SPIN PROFICIENCY
Inasmuch as we spend a lot of time flying near the stalling speed, proficiency in spin recognition, prevention and recovery should be a prerequisite for flying a glider under any circumstances. But definitely do not expose yourself to the additional stress and workload of low level thermalling over unfamiliar terrain until you have reached the level of spin training and practice which makes spin entry recognition and the correct control input for recovery intuitive. When the work load is high, as it is when trying to latch on to a feeble scrap of a thermal at pattern altitude while scrutinizing your selected field for obstacles at the same time, is when you are most likely to experience an inadvertent spin entry - better be ready.
To be fully effective, spin practice should be done in the glider to be flown, as spinning characteristics will vary from one glider to another. If you have never spun a glider, be sure you get spin training in a two-seater with a qualified instructor prior to practicing on your own.
In order for this spin training to be of any value, it needs to be done in a glider that truly spins. Spin demonstration in a glider such as a Schweizer 2-33 is detrimental to spin training as it will inevitably leave anyone with the impression that it is virtually impossible to spin a glider, and recovery is instantaneous regardless of control input. Nothing could be further from the truth. I do not know of any single-seat glider that will not spin, given the right conditions. If you fly a glider long enough, sooner or later you will experience an inadvertent spin entry.
WEATHER CONDITIONS
In windy and turbulent conditions you need to raise the minimum altitude for attempting a save. There are days when it is not safe to thermal below 1,000 ft regardless of your experience level.
RADIO USAGE
Needless to say, the radio should have been off long before you get to this stage, if it isn't, by all means turn it off. Scratching around close to the ground, checking your selected field for slope, wires, fences and scrutinizing the intended touch-down area for stones, holes etc. while frantically attempting to center this scrap of a thermal you stumbled into at the last possible moment and, by the way, flying the glider at the same time, is most certainly the most demanding flying you will ever be faced with. Trust me, this will keep your mind fully occupied. The radio will not help you stay up, it will not help you land, and nothing else is of any consequence.
Incidentally, people have crashed because they were preoccupied with the radio. If you should fail to stay-up, any message to your crew can much better be transmitted at your leisure when you are safely on the ground. Besides, there is plenty of time, you won't be doing anything else that afternoon.
Even listening to a transmission is distracting. "KI, this is 1G, I am about 2 miles SW of Loon Lake at 8,000 ft, climbing at 7 knots." This may be interesting information for somebody, but to you, when struggling at 600 ft, it is totally useless. Worse than useless, because it can't help but divert some of your attention from the task at hand at a time when you can least afford it.
Hence, your best bet is to turn the radio off. My policy is to turn the radio off when I get down to 1,500 ft. I suggest you do likewise.
CRITERIA
The criteria I have used for many years is simply this, "If I can afford to lose 200 ft, I will try a turn. If I can't afford to lose 200 ft, I proceed with the pattern." Why 200 ft, you may ask. Well, on the average soaring day it is reasonable to expect areas of sink in the magnitude of 600 ft per minute. It is also reasonable to expect that you will turn in the wrong direction, which could place you very nicely in 600 ft per minute down. The rate of turn will probably be about 20 sec. per 360°. Consequently, you may be 200 ft lower by the time you complete the circle. If you expected this and planned for it, you won't get in trouble.
Let's assume you meet all the prerequisites. You have the experience outlined above, you are current and thoroughly familiar with the glider. You are on another cross-country flight. Things didn't go as expected, you are in the pattern to an apparent inevitable landing in an alfalfa field. You are half way along the downwind leg, and you feel a surge. Should you try a circle? If there will be enough height left to complete the pattern if you lose 200 ft, albeit, a little on the low side, but not uncomfortably so, you can give it a try. Hold off for a brief moment, if it feels solid roll into a 45° bank. With a little bit of luck, you may find yourself going up half way around so that you haven't lost or gained any height at the completion of the circle. Incidentally, this is about the best you can hope for on the first circle as the thermals tend to be small at that level. It is highly unlikely you will gain much during the first few circles. If you didn't lose any altitude, try another circle and if you can keep the variometer on zero, stay with it. The combination of your presence, helping to break the thermal free, and your centering efforts will in many cases eventually improve the climb rate.
However, if you continue to merely hold your own, you must be prepared to abandon the effort before you drift too far from the field. In case you eventually are forced to give it up, your effort will not have been completely futile as you gained some extra time to further scrutinize your selected field.
POSITION
Your position with respect to your chosen field is as much a consideration as your altitude. Crowding the pattern must be avoided. You should be in a comfortable position, off to the side. The distance to your selected field is all as important as your altitude, you may be high enough to circle, but if a 200 ft. loss will prevent you from reaching the entry point of the pattern at the appropriate height, don't try it.
If you do find yourself too low for a full, standard pattern, don't insist on it. The prime objective is to prevent the turn to final from being below 200 ft.
THE CLIMB
When starting to climb, you need to make a real effort to keep concentrating. There is a natural tendency to heave a sigh of relief and relax just a little when reaching a thousand feet, promptly losing concentration and the thermal.
A cease of climb at a 1,000 ft is not always caused by inattention. It is rare, but there are times when a thermal does not go any higher. Sometimes a thermal draws in excessive amounts of cold air and loses its buoyancy. A thermal may fade away when drifting in to the shade. At times like this, keep in mind that on any specific day, the thermals tend to sprout from the same source. Consequently, if you lose the lift before you get high enough to continue on course your best bet is to go back to the spot where you found it. Chances are there will be another bubble coming along which may have enough temperature differential to continue all the way up to the inversion.
ACCIDENTS
Most accidents occurring during attempts at low saves are attributable to:
• Distracted by the radio.
• Slow and shallow-banked turns.
• Work overload.
• Forgetting to fly the glider.
• Inadequate spin training.
• Not knowing when to quit.
As I was flying through the air,
I found some lift that wasn't there.
It wasn't there again today -
That's twice I've had to land away.
FUNDAMENTALS OF LOW SAVES
• BE SURE THE RADIO IS OFF.
• WHEN LOW, USE EXTRA AIRSPEED AND WELL-BANKED TURNS.
• AN AUDIO VARIOMETER IS A MUST.
• WHEN FACED WITH YOUR FIRST FIELD LANDINGS DO NOT ATTEMPT TO THERMAL BELOW 800 FT.
• STAY WITHIN YOUR CAPABILITIES.
• DON'T DO ANYTHING YOU ARE UNCOMFORTABLE WITH.
• NEVER THERMAL AT LOW LEVELS UNLESS YOU ARE EXPERIENCED AND CURRENT.
• NEED TO BE FAMILIAR WITH THE GLIDER.
• THE TASK OF FLYING THE GLIDER MUST BE INTUITIVE.
• MUST BE PROFICIENT AND CURRENT IN SPINS.
• RAISE YOUR MARGIN OF SAFETY ON WINDY AND TURBULENT DAYS.
• NEVER TRY A CIRCLE UNLESS YOU CAN AFFORD TO LOSE 200 FT.
• YOUR POSITION WITH RESPECT TO THE CHOSEN FIELD IS AS RELEVANT AS HEIGHT.
• DON'T FORGET TO FLY THE GLIDER.
• DON'T LOSE CONCENTRATION AFTER GAINING A FEW HUNDRED FEET.
With grace and beauty,
Strength and cunning
She'll stay aloft - until;
Inevitably - she loses
And must glide earthward
And lie there helpless
Lovesick for the sky.
Leon Roskilly
