The ball in the slip/skid indicator also indicates coordinated flight, slips, and skids in a similar manner as the head of the
yaw string. When using this instrument for coordination, the pilot can apply rudder pressure on the same side as the ball
(step on the ball). The pilot's body pressure against the sides, bottom, and back of the seat respond in the same way as
the ball, and many pilots can sense the force that pushes to one side or the other rather than straight down into the seat.
Pilots can correct for uncoordinated condition by using appropriate rudder and aileron control pressures simultaneously or
individually to coordinate the glider.
Roll-In
Before starting any turn, the pilot should clear the airspace in the direction of the turn. When applying aileron to bank the
glider, the down aileron deflection on the rising wing generates greater drag while the raised aileron on the lowering wing
generates less drag. This difference in drag causes the glider to yaw toward the rising wing or away from the intended
direction of turn. When applying pressure to the ailerons to begin a turn and to counteract this adverse yaw, the pilot should
also apply rudder pressure in the direction of turn. If using excess rudder pressure, the nose appears to yaw before the pilot
establishes the bank. If using insufficient rudder pressure, the nose initially moves in the wrong direction as the pilot begins
the turn. If using the correct amount of rudder pressure, the nose starts to move along the horizon, increasing its rate of
travel proportionately as the bank increases.
After establishing a medium banked turn, the pilot may relax pressure applied to the aileron control. The glider tends to
remain at the selected bank with no further tendency to yaw without aileron deflection. As a result, the pilot may also relax
pressure applied to the rudder pedals, and the rudder streamlines itself with the direction of the slipstream. If the pilot
maintains constant rudder pressure after establishing the turn, the glider skids to the outside of the turn. If the pilot makes
a conscious effort to center the rudder rather than let it streamline itself to the turn, the pilot may inadvertently apply some
opposite rudder pressure. This forces the glider to slip to the inside of the turn. The yaw string or ball in the slip/skid moves
as described above.
As the angle of bank increases from a shallow bank to a medium bank, the airspeed of the wing on the outside of the turn
increases in relation to the inside wing. The additional lift developed on the outside wing balances the lateral stability of the
glider. Therefore, the pilot does not use aileron pressure to maintain a medium bank. If the bank increases from a medium
to steep, the radius of turn decreases even further. The greater lift of the outside wing will cause the bank to steepen, and
the pilot should use opposite aileron to hold the bank constant. Because the outboard wing develops more lift, it also has
more induced drag. This causes a slid during steep turns that the pilot corrects with rudder pressure.
To establish the desired angle of bank, the pilot should use visual reference points on the glider, the earth’s surface, and
the natural horizon. The beginning pilot may lean away from or into the turn but should remain aligned with the seat. Any
deviation prevents proper use of visual references. Large application of aileron pressure may produce rapid roll rates and
allow little time for corrections before reaching the desired bank. Slower (small control displacement) roll rates provide
more time to make necessary pitch and bank corrections.
While establishing the desired angle of bank and during the turn, the pilot should use elevator pressure to maintain the
desired airspeed. Throughout the turn, the pilot should cross-check the airspeed indicator to verify the proper pitch. The
cross-check and instrument scan should include outside visual references. If the glider gains or loses airspeed, the pilot
should adjust the pitch attitude in relation to the horizon. During all turns, the pilot uses aileron, rudder, and elevator
control to correct minor variations in pitch and bank.
Roll-Out
The roll-out from a turn involves application of coordinated flight controls in the opposite direction. Aileron and rudder
application occur in the direction of the roll-out or toward the high wing. As the angle of bank decreases, the pilot uses
elevator pressure, as necessary, to maintain airspeed.
Since the glider continues turning while in a bank, the roll-out should begin before reaching the desired heading. The
amount of lead to roll-out on the desired heading depends on the degree of bank used in the turn. Normally, pilots use one-
half the bank angle. For example, if the bank is 30°, the pilot leads the roll-out by 15°. As the wings become level, the pilot
can smoothly relax control pressures, so the controls neutralize as the glider returns to straight flight. As the roll-out occurs,
outside visual references provide indications that the wings have leveled, and the turn stopped.
Common errors during a turn include:
• Failure to clear turn.
• Nose movement before the bank starts—rudder is being applied too soon.
• Significant bank before the nose moves, or nose movement in the opposite direction—the rudder is being applied
too late.
• Up or down nose movement when entering a bank—excessive or insufficient elevator is being applied.
• Rough or abrupt use of controls during the roll-in and roll-out.
• Failure to establish and maintain the desired angle of bank.
• Overshooting/undershooting the desired heading.
Steep Turns
In thermaling flight, small-radius turns can keep the glider in or near the core of a thermal updraft. To keep the radius of
turn small, the pilot can establish a steep bank while maintaining an appropriate airspeed, such as minimum sink or best
glide speed. The pilot should also understand that as the bank angle increases, the stall speed increases.
A steep turn results in a rapid heading change, and the pilot should clear the area for other traffic. While banked steeply, the
rudder may act like an elevator. A little top rudder helps keep the nose-up attitude. If the pilot does not add sufficient back
pressure or top rudder to maintain the desired airspeed as the bank angle steepens, the glider may enter a spiral dive. In
summary, during a coordinated steep turn, the pilot uses back pressure on the elevator for airspeed control, aileron pressure
against the raised wing for bank control, and top rudder pressure to maintain pitch attitude.
Common Errors
Common errors during steep turns include:
• Failure to clear turn.
• Uncoordinated use of controls.
• Loss of orientation.
• Failure to maintain airspeed within tolerance.
• Inappropriate division of attention inside and outside the glider.
• Unintentional stall, spin, or spiral dive.
• Excessive deviation from desired heading during roll-out.
Slow Flight
Maneuvering during slow flight demonstrates the flight characteristics and degree of controllability of a glider at reduced
speeds. Pilots should develop awareness of the flight characteristics of any glider they fly to recognize and avoid stalls
that may inadvertently occur during low airspeed flight used in takeoffs, climbs, thermaling, and approaches to landing.
Maneuvering during slow flight develops the pilot’s sense of feel and ability to use the controls, and to improve proficiency.
Pilots should use outside visual references to maintain the desired pitch attitude as well as periodically scan the airspeed
indicator.
The maneuver starts from either best glide speed or minimum sink speed at a safe altitude. The pilot smoothly and gradually
increases pitch attitude. While the glider airspeed decreases, the position of the nose in relation to the horizon will rise as
the angle of attack increases. Since lift diminishes with the square of airspeed, the increase in angle of attack to keep lift
constant becomes more pronounced as airspeed decays. As speed continues to decrease and approach the airspeed at which
any further increase in angle of attack or load factor would result in a stall, the glider reaches the edge of its flight envelope
at a minimum controllable airspeed. In smooth air and with no turning, minimum controllable airspeed is lower than in
rough air. If in turbulence, the pilot should fly with a sufficient speed margin above the minimum controllable airspeed
to avoid a stall. During slow flight or during flight at minimum controllable airspeed, the pilot should continually use the
horizon to maintain desired pitch attitude and glance at the airspeed indicator to maintain the target airspeed. Trimming the
glider, as necessary, compensates for changes in control pressure. The diminished effectiveness of the flight controls during
slow unaccelerated flight should familiarize the pilot with the characteristics and feel of flight near the 1G stalling speed.
After establishing a slow airspeed in straight flight, turns further demonstrate the glider’s characteristics at that selected
airspeed. During turns, the pilot should decrease pitch attitude as needed to maintain airspeed. Otherwise, as bank steepens,
the increase in load factor may result in a stall. A stall may also occur in a turn because of abrupt or rough control
movements or turbulence, which increase load factor. Abruptly raising the flaps during minimum controllable airspeed
flight also results in sudden loss of lift and may cause a stall. The actual speed at which a stall occurs also depends upon
conditions such as the gross weight and CG location.
Pilots should also practice slow flight with the glider in different configurations such as with spoilers/dive brakes, flaps,
and landing gear extended and retracted. This provides additional understanding of the changes in pitch attitude caused by
the increase in drag in different configurations.
Common Errors
Common errors during slow flight maneuvers include:
• Failure to clear the area.
• Failure to establish or to maintain desired airspeed.
• Improper use of trim.
• Rough or uncoordinated use of controls.
• Excessive deviation from desired heading during roll-out.
• Failure to recognize indications of a stall.
Stall Recognition & Recovery
A stall can occur at any airspeed or attitude. In a powered glider, a stall can also occur at any power setting. Intentional
stalls familiarize the pilot with the conditions that produce stalls, assist in recognizing an approaching stall, and develop the
skills necessary to prevent or recover from a stall. The pilot should learn the stall characteristics and recovery procedures
of the glider being flown.
Stall accidents usually result from an inadvertent stall at a low altitude in which a recovery was not accomplished prior to
contact with the surface. The longer it takes to recognize the approaching stall, the more complete the stall becomes, and
the greater the expected altitude loss. To mitigate the risk involving loss of altitude during recovery, pilots should practice
stalls at an altitude that allows recovery within gliding distance of a landing area and no lower than 1,500 feet AGL.
Many gliders do not have an electrical or mechanical stall warning device. Pilots should recognize an approaching stall by
sight, sound, and feel. The following cues should warn the pilot of an approaching stall.
1. Vision—visualizing the relative wind and angle of attack. Yaw string (if equipped) movement from normal flight
position.
2. Hearing—a change in sound due to loss of airspeed.
3. Feeling—As a stall begins, the pilot starts to feel airframe buffeting or aerodynamic vibration.
A. Kinesthesia, or the sensing of changes in direction or speed of motion, if properly developed, warns of a decrease
in speed or the beginning of a settling, or mushing, of the glider.
B. As speed decreases, the resistance to pressure on the controls becomes progressively less. The ailerons, elevator,
and rudder have significantly less authority and require more movement to control the glider. Under low-speed
stalling conditions, the lag between control movements and the response of the glider becomes more pronounced.
Pilots should always make clearing turns before performing stalls. During the practice of intentional stalls, the major
objective is not to learn how to stall a glider, but rather to learn how to recognize an approaching stall and take prompt
corrective action. The recovery actions involve a coordinated recovery.
First, at the indication of a stall, the pilot should immediately lower the pitch attitude and AOA by releasing the back-
elevator pressure or by moving the elevator control forward. This lowers the nose and returns the wing to an effective
AOA. The amount of elevator control pressure or movement to use depends on the design of the glider, the severity of
the stall, and proximity to the ground. In some gliders, a moderate movement of the elevator control—perhaps slightly
forward of neutral—suffices, while others may require a forcible push to the full forward position. However, an excessive
negative load on the wings caused by excessive forward movement of the elevator may impede, rather than hasten, the stall
recovery. The object is to reduce the AOA sufficiently to allow the wing to regain lift. [Figure 7-41]
Buffet
Stall
Initiate recovery
Increase airspeed
Recovery in straight glide
Flight path
Relative wind
Figure 7-41. Stall recovery.
When practicing stalls in a powered glider, the pilot should experience the stall and recovery with and without the engine
running. In a stall with power available, the pilot should smoothly and promptly apply maximum allowable power during
the stall recovery while lowering the pitch attitude to increase the self-launching glider’s speed and assist in reducing the
AOA. The applied power reduces the loss of altitude. Maximum allowable power applied at the instant of a stall does not
usually cause overspeeding of an engine equipped with a fixed-pitch propeller, due to the heavy air load imposed on the
propeller at low airspeeds. However, the pilot may reduce the power as airspeed increases so the airspeed or rpm does not
become excessive.
Introduction to stalls should consist of approaches to stalls with recovery initiated at the first airframe buffet or when
the pilot recognizes partial loss of control. Using this method, pilots become familiar with the initial indications of an
approaching stall without fully stalling the glider. Whether in an unpowered or powered glider, stall recovery occurs by
reducing the angle of attack, leveling the wings with coordinated control inputs, and returning to straight flight. Whenever
practicing stalls while turning, the pilot should maintain a constant bank angle until the stall occurs.
Stalls in most gliders move progressively outward from the wing roots (where the wing attaches to the fuselage) to
the wingtips. This occurs because the wings have a smaller angle of incidence at the tips than at the wing roots. When
an exceedance of the critical angle of attack results in a stall, the outer part of the wing can retain some aerodynamic
effectiveness. During recovery from a stall, the return of lift begins at the tips and progresses toward the roots, thus giving
the ailerons authority to level the wings.
Using the ailerons requires finesse to avoid an aggravated stall condition. For example, if the right wing drops during the
stall and the pilot uses excessive aileron control to the left to raise the wing, the aileron that deflects downward on the right
wing would change the camber of that portion of the wing. The increased AOA could cause the wing to stall at the tip. The
increase in drag created by the high AOA on that wing might cause the airplane to yaw in that direction. This adverse yaw
could result in a spin unless the pilot maintains directional control with rudder or reduces aileron deflection.
Even with application of excessive aileron pressure, a spin does not occur if the pilot maintains directional (yaw) control
using timely application of coordinated rudder pressure. Therefore, the pilot should use rudder properly during both
entry and recovery from a stall. The rudder in stall recovery counteracts any tendency of the glider to yaw. A pilot using
correct stall recovery technique decreases the pitch attitude by applying forward elevator pressure to reduce the AOA and
simultaneously maintains directional control with coordinated use of the aileron and rudder.
Advanced stalls include secondary, accelerated, and crossed-control stalls. These stalls expand a pilot's stall/spin awareness.
Secondary Stalls
A secondary stall occurs during a recovery from a preceding stall. It may occur when the pilot attempts to complete a stall
recovery with abrupt control input or before the glider has regained sufficient flying speed, which results in a repeated stall.
When this stall occurs, the pilot should release back-elevator pressure as in a normal stall recovery.
Accelerated Stalls
Actual accelerated stalls occur most frequently during turns in the traffic pattern close to the ground while maneuvering
the glider for the approach. A glider pilot should recognize signs of an imminent accelerated stall and take prompt action
to prevent a completely stalled condition to avoid loss of altitude or a spin.
Performing intentional accelerated stalls can show the pilot how these stalls occur, enhance pilot recognition of conditions
that can cause a stall, and reinforce timely and proper recovery action. During training at a safe altitude, pilots should learn
how to recover at the first indication of a stall or immediately after the stall occurs.
A glider at a given weight consistently stalls at the same indicated airspeed in unaccelerated 1G flight. However, the
glider stalls at a higher indicated airspeed when the pilot imposes a maneuvering load as in a steep turn or pull-up. These
maneuvers rely on an increased angle of attack to generate the lift used to change the path of the glider. If the demand for
additional lift exceeds the critical angle of attack, an accelerated stall occurs and could surprise a pilot. Depending on the
wing configuration and quality of coordination, one wing may stall prior to the other wing. If the wings have a slight or
pronounced sweep, one wing can rapidly develop more lift than the other, and a spin could occur before the pilot can react.
For this reason, pilots should avoid turning too tightly in the traffic pattern to prevent exceeding the critical angle of attack
and any resulting accelerated stall at a low altitude.
Pilots should not perform accelerated maneuver stalls in any glider if the GFM/POH prohibits this maneuver. If permitted,
training for this maneuver occurs with a bank of approximately 45° and never at a speed greater than the manufacturer’s
recommended airspeed for the maneuver or the design maneuvering speed specified for the glider. At the design maneuvering
speed, the glider will stall before application of full aerodynamic control can exceed the glider’s limit load factor. The stall
unloads the wings, cuts off the acceleration, and prevents structural damage.
A glider slipping toward the inside of the turn at the time the stall occurs tends to roll rapidly toward the outside of the
turn as the nose pitches down and the outside wing stalls first. A glider skidding toward the outside of the turn tends to roll
to the inside of the turn because the inside wing stalls first. During a stall in a coordinated turn, the glider’s nose pitches
away from the pilot just as it does in wings-level stall since both wings stall simultaneously. The configuration of the
wings has a strong influence on exactly how a glider reacts to different airflows. A pilot should fly the specific glider into
these situations at a safe altitude to determine how the glider will react. This training should condition the pilot to avoid an
accelerated stall that could result in an accident.
As with any deliberate stall, the area should be clear of other aircraft. From straight flight at maneuvering speed or less,
the pilot should roll the glider into a steep banked (45° maximum) turn and gradually apply back-elevator pressure. After
establishing the bank, the pilot smoothly and steadily increases back-elevator pressure. The resulting apparent centrifugal
force pushes the pilot’s body down in the seat, increases the wing loading, and decreases the airspeed. The pilot should
firmly increase back-elevator pressure until a definite stall occurs.
When the glider stalls, recovery involves the prompt release of back-elevator pressure. In an uncoordinated turn, one wing
may tend to drop suddenly, causing the glider to roll in that direction. If this occurs, the pilot should lower the nose and use
coordinated control pressure to return glider to wings-level, straight flight.
An accelerated stall could occur any time the pilot applies excessive back-elevator pressure or increases the AOA too rapidly.
Although demonstrated from a steep turn, the maneuver allows the pilot to experience accelerated stall characteristics and
develop the ability to recover instinctively at the onset of a stall at any other-than-normal stall speed or flight attitude.
Crossed-Control Stalls
A crossed-control stall demonstration maneuver shows the effect of improper control technique and emphasizes the
importance of coordinated control pressures whenever making turns. This type of stall occurs with the controls crossed—
aileron pressure applied in one direction and rudder pressure in the opposite direction while exceeding the critical AOA.
[Figure 7-42]
Left aileron deflected up
Right aileron deflected down
Rudder deflected right
Figure 7-42. Demonstrating a crossed-control approach to a stall at altitude.
This stall most commonly occurs during a poorly planned and executed base-to-final turn when overshooting the centerline
of the runway during the turn. Normally, the pilot should correct by increasing the rate of turn using coordinated aileron and
rudder. At the relatively low altitude of a base-to-final approach turn, improperly trained pilots sometimes fear steepening
the bank to increase the rate of turn and incorrectly use excessive rudder pressure to yaw the airplane.
The addition of rudder pressure on the inside of the turn causes the speed of the outer wing to increase, creating greater
lift on that wing. To keep that wing from rising and to maintain a constant angle of bank, the pilot applies opposite aileron
pressure. The added inside rudder pressure also causes the nose to lower in relation to the horizon. Consequently, the pilot
adds additional back-elevator pressure to maintain a constant pitch attitude. The resulting turn uses rudder applied in one
direction, aileron in the opposite direction, and excessive back-elevator pressure—a pronounced crossed-control condition.
The down aileron on the inside of the turn helps drag that wing back, slowing it and decreasing its lift. This further causes
the glider to roll. The roll may be so fast that it is possible the bank will be vertical or past vertical before the pilot can stop
and reverse it.
The demonstration of the maneuver should occur at a safe altitude because of the possible extreme nose-down attitude and
loss of altitude that may result. Before demonstrating this stall, the pilot should clear the area for other air traffic. As the
pilot establishes the gliding attitude and airspeed, the glider should be retrimmed. With the glide established, the pilot rolls
the glider into a medium banked turn to simulate a final approach turn that would overshoot the centerline of the runway.
During the turn, the pilot applies excessive rudder pressure in the direction of the turn while holding bank constant with
opposite aileron pressure. At the same time, increased back-elevator pressure keeps the nose from lowering.
All these control pressures increase until the glider stalls. When the stall occurs, releasing the control pressures and
simultaneously decreasing the AOA initiates the recovery. In a crossed-control stall, the glider often stalls with little
warning. The nose may pitch down, the inside wing may suddenly drop, and the glider may continue to roll to an inverted
position. This is usually the beginning of a spin.
The pilot should recover before the glider enters an abnormal attitude (vertical spiral or spin) by returning to wings-level,
straight flight using coordinated control inputs. The pilot should recognize imminent stall and take immediate action to
prevent a completely stalled condition. This type of stall during an actual approach to a landing would likely result in
ground contact before recovery.
Common Errors
Common errors during advanced stalls include:
• Improper pitch and bank control during straight-ahead and turning stalls.
• Rough or uncoordinated control procedures.
• Failure to recognize the first indications of a stall.
• Premature recovery when demonstrating a full stall.
• Poor recognition and recovery procedures.
• Excessive altitude loss, excessive airspeed, or encountering a secondary stall during recovery.
Chapter Summary
Regardless of the launch method, pilots and ground personnel should have the ability to communicate effectively. This
not only includes knowing appropriate signals, but also knowing when to use them. Briefing of all personnel before
takeoff enhances the safety of a glider operation. Takeoffs normally occur with the assistance of a wing runner; however,
the chapter also discusses unassisted takeoff techniques that experienced pilots may use. The chapter discusses various
maneuvers including level glides, turns, steep turns, release procedures, slack line avoidance and recovery, and boxing
the wake. A pilot can discern turn coordination using a yaw string or inclinometer, and the chapter gives practical advice
regarding the use of these instruments when adjusting from a slip or skid. Pilots should understand the traffic pattern
procedures for every field they use. A minimum altitude for the initial point (IP) of the traffic pattern should allow the
glider pilot to maneuver to the landing field and make a successful landing in a variety of conditions including normal,
crosswind, and downwind. A pilot should know how to make a stable final approach to an aiming point, use drag devices
and slips to control the descent angle, and land in a crosswind with no side load. Pilots should recognize various stalls and
know how to avoid conditions that could result in any unintentional stall. Flight at minimum controllable airspeed and stall
training at a safe altitude build pilot awareness of and resistance to unsafe operating conditions.