Forward slip Sideslip
Figure 7-34. Forward slip and sideslip.
Common Errors
Common errors when performing a slip include:
• Improper glidepath control.
• Improper use of slips.
• Improper airspeed control.
• Improper correction for crosswind.
• Improper procedure for touchdown/landing.
• Poor directional control during/after landing.
• Improper use of spoilers, air brakes or dive brakes.
Crosswind Landing
Crosswind landings rely on a crab to correct for the effects of the wind on the final approach. A pilot performs a crab by
turning the glider to a heading sufficiently into the crosswind to fly a straight track along the desired final approach path.
A glider in a crab tracks the extended centerline of the landing area in coordinated flight. [Figure 7-35A]
WIND
The crab method using coordinated flight to track
the extended centerline of the landing area
The pilot lowers the upwind wing into the wind direction
and uses opposite rudder deflection to maintain landing
direction. Using this combination of flight control input,
the pilot lands the aircraft with the least amount of side
load possible on the landing gear.
WIND
Figure 7-35. Using the crab method to track the extended centerline of the landing area (A). Controlling side drift by adjusting the
glider into the wind before landing (B).
Pilots should transition from a crab to a sideslip on short final or prior to beginning the round out and flare. When the pilot
transitions to a side slip the pilot keeps the glider aligned with the runway in uncoordinated flight using opposing rudder
and aileron control. For effectiveness, the pilot aligns the nose with the runway using the rudder first. The pilot then lowers
the wing on the upwind side as necessary to oppose the drift that develops from exposure to the crosswind component.
[Figure 7-35B] Although a slip increases the sink rate of the glider, the pilot may position the spoilers/dive brakes to
compensate for this additional sink rate.
Common Errors
Common errors during approach and landing include:
• Failure to complete the landing checklist in a timely manner.
• Inadequate wind drift correction on the base leg.
• An overshooting, undershooting, too steep, or too shallow a turn onto final approach.
• Poor coordination during turn from base to final approach.
• Improper glidepath control.
• Improper use of flaps, spoilers/dive brakes.
• Improper airspeed control.
• Unstabilized approach.
• Improper correction for crosswind.
• Improper procedure for touchdown/landing.
• Poor directional control during/after landing.
• Improper use of wheel brakes.
Downwind Landing
Downwind landings present special hazards and pilots should avoid this type of landing if possible. However, factors
like gliderport/airport design, runway slope, or obstacles or high terrain at one end of the runway may dictate downwind
takeoff and landing procedures. Emergencies or a launch failure and turn back at low altitude can also result in a downwind
landing. On downwind approaches, pilots should plan a shallower approach angle and may use the spoilers/dive brakes or a
forward slip, as necessary, to achieve the desired glidepath or to descend more quickly after passing over an obstacle. The
pilot should use a normal approach airspeed during a downwind landing and understand that the increase in groundspeed
increases the approach area and runway length needed for the landing.
The increased distance for landing due to higher speed can be determined by dividing the actual touchdown speed by the
normal touchdown speed and squaring the result. For example, if the tailwind is 10 knots and the normal touchdown speed
is 40 knots, the actual touchdown speed is 50 knots. (50/40)*2 = 1.56 and the landing distance increases 56 percent over
the normal landing distance.
After touchdown, the pilot should use the wheel brake and all available drag devices to reduce groundspeed and stop within
the available distance. Landing with a tailwind means a loss of control effectiveness at a higher groundspeed and requires
more braking action.
Common errors during downwind landing include:
• Improper glidepath control.
• Improper use of slips.
• Improper airspeed control.
• Improper correction for wind.
• Improper procedure for touchdown/landing.
• Poor directional control during/after landing.
• Improper use of wheel brakes.
Landing a Self-Launching Glider
If planning a landing under power, the pilot should perform the engine restart checklist, allow sufficient time for the engine
to warmup, and ensure that all systems operate properly. The pilot of a self-launching glider should have an alternate
landing area available to mitigate the risk associated with decreased performance and higher drag should the engine fail to
start and then fail to retract.
The pilot should fly the traffic pattern and land into the wind and with an approach angle that avoids all obstacles. The
landing area dimensions should allow for touchdown and roll-out within the performance limitations of the self-launching
glider. The pilot should also take into consideration any crosswind conditions and the landing surface. After touchdown,
the pilot should maintain directional control, slow the self-launching glider, and clear the landing area. The pilot should
complete the after-landing checklist when stopped and clear of the landing area.
Common Errors
Common errors exclusive to self-launching gliders during landing include:
• Attempting engine restart with insufficient time or altitude
• Mismanagement of engine restart.
• Not accounting for decreased glide ratio with the engine pylon extended.
• Failing to have a suitable field available in case the engine does not start.
• Landing with a side load due to parallax in powered gliders with side-by-side seating.
• Failure to use the appropriate checklist.
Nosewheel Glider Oscillations During Launches & Landings
Some gliders feature pneumatic tires on three wheels—a main wheel, tail wheel, and nose-wheel. The large main tire acts
like a fulcrum and prevents both the nose tire and the tail tire from contacting the ground at the same time. With the glider
in motion and if the pneumatic nose-wheel remains in contact with the ground, any bump compresses the nose-wheel tire.
When the nose-wheel tire rebounds after hitting a bump at a fast ground speed, a pitch up can occur that places the tail
wheel in contact with the runway, and it may compress and rebound as well.
With sufficient lift, porpoising may result if the nosewheel and tail wheel alternately hit the runway, compress, and
rebound. Because this type of porpoising can damage the glider fuselage, the pilot should use elevator control to lift the
nosewheel off the runway as soon as practicable during the takeoff roll so that only the glider’s main wheel contacts the
ground. During the landing, the pilot should hold the glider off during the flare, allow the main wheel and tail wheel touch
simultaneously, and then hold the nosewheel off the ground during the rollout.
Tailwheel/Tailskid Equipped Glider Oscillations During Launches & Landings
Many gliders have a tail wheel. When loaded and ready for flight, these gliders have both the main wheel and a tail wheel/
tailskid in contact with the ground, and the center of gravity location remains aft of the main wheel(s). While any upward
thrust on the main landing gear tends to pitch the nose of the glider upward, the ground contact of the tail wheel or tail skid
limits the change in pitch attitude.
A vigorous main wheel bump on the runway surface during the takeoff roll may push the glider into the air momentarily.
At low airspeeds and with minimal elevator control, pilot over control of the elevator after an unexpected bounce or launch
may result in PIOs. [Figure 7-36]
1 Tire uncompressed
2 Tire compressing during
hard landing or impact
with runway bump.
3 Maximum compression
of tire
4 Tire rebounds, launching
glider airborne
Figure 7-36. Pneumatic tire rebound.
During landing, main wheel contact with the ground before the tailwheel or tailskid results in compression and rebound of
the pneumatic main tire, which may raise the nose of the glider, increase the angle of attack, and cause resumption of flight.
Pilot overcontrol of the elevator may then lead to PIOs.
After Landing & Securing
After landing and stopping, the pilot or crew moves the glider clear of all runways. If parking the glider for a short interval
between flights, an appropriate parking spot should not interfere with other gliderport/airport users or create a hazard.
Pilots should close glider canopies, which are easily damaged if not secured. Because gliders can suffer wind damage, the
glider should be secured if left unattended. Protecting the glider from wind may involve securing a wingtip with a weight
or tie down. The manufacturer’s handbook should have the recommended methods for securing the glider.
When finished with flying for the day, the pilot or crew should move the glider to the tiedown area and secure it in
accordance with the recommendation in the GFM/POH. The tiedown anchors should be strong and secure. Any external
control lock should be large, well-marked, and brightly painted. Pitot tube covers should use brightly colored materials for
high visibility. Any canopy cover should have a soft inner surface that cannot scuff or scratch the canopy.
If storing the glider in a hangar, persons moving the glider should exercise care and maintain awareness of objects or other
aircraft in the hangar. When parked in a hangar, the crew normally chocks the main wheel and tailwheel. Wing stands
under each wingtip keep the glider in a wings-level position. If stored with one wing high, a weight should be placed on
the lowered wing to hold it down.
If disassembling the glider for storage in a trailer, individuals tow the glider to the trailer area and normally align the
fuselage with the long axis of the trailer. The pilot or crew should follow the disassembly checklist in the GFM/POH and
stow the glider components securely in the trailer. Storage includes collection and stowage of all tools, closing trailer doors
and hatches, and securing the trailer against wind and weather.
Performance Maneuvers
Straight Glides
The glider pilot holds a constant heading and airspeed during a straight glide and uses a prominent point on the ground in
front of the glider as a heading reference. During a straight glide, each wingtip should appear at an equal distance relative
to the horizon. Straight glides should be coordinated as indicated by a centered yaw string or slip-skid ball. With the wings
level, the pilot establishes a pitch attitude relative to a distant point on or below the forward horizon. The pilot can hold a
constant pitch attitude and a constant airspeed with little to no control pressure using the elevator trim control.
The glider pilot should listen for airflow noise changes. Any changes in airspeed or coordination cause a change in the wind
noise. While gusts cause the sound and airspeed to change momentarily, the pilot can ignore the sound of gusts and hold
the glider at a constant pitch attitude to maintain airspeed control.
The glider pilot should learn to fly through a wide range of airspeeds, from minimum controllable airspeed to maximum
allowable airspeed. Glider pilots should also note the difference in control pressure with airspeed changes. This provides
the pilot with a complete understanding of the feel of the controls of the glider. If the glider equipment includes spoilers/
dive brakes and/or flaps, the glider pilot should become familiar with the changes that occur in pitch attitude and airspeed
when using these controls.
Common Errors
Common errors during straight glides include:
• Rough or erratic pitch attitude and airspeed control.
• Rough, uncoordinated, or inappropriate control applications.
• Failure to use trim or improper use of trim.
• Improper use of controls when using spoilers, dive brakes, and/or flaps.
• Prolonged uncoordinated flight—yaw or ball not centered.
Turns
Turning involves all three flight controls: ailerons, rudder, and elevator. For purposes of this discussion, turns divide into
the following three classes as shown in Figure 7-37.
20°
45°
60°
Shallow turn
Medium turn
Steep turn
Figure 7-37. Shallow, medium, and steep turns.
• Shallow turns (less than approximately 20° of bank) include those in which the inherent lateral stability of the glider
levels the wings unless the pilot maintains some aileron pressure to maintain the bank.
• Medium turns result from approximately 20° to 45° of bank. Lateral stability results in little to no aileron control
pressure to maintain the bank angle.
• Steep turns result from a degree of bank 45° or more. During a steep turn, the overbanking tendency of a glider
overcomes lateral stability, and the bank increases without opposing aileron application.
Most training gliders have a yaw string, typically a piece of yarn taped to the canopy. Pilots refer to the taped end as
the head and the free end as the tail. During flight, comparing the head and tail of a yaw string identifies coordinated
flight, slips, and skids. During coordinated flight, the yaw string flows straight back on the windscreen (perpendicular to
the longitudinal axis) [ Figure 7-38]. During a slipping turn, the head of the yaw string is to the inside of the turn when
compared to the tail. [ Figure 7-39] During a skidding turn, the head of the yaw string is to the outside of the turn when
compared to the tail. [Figure 7-40].
30.0
29.929.8
I00 FEET
CALIBRATED
TO
20,000 FEET
ALT
OFF
GO
NAV
NET AVG
PULL
PUSH
HW
DIST
ALT
PUSH
4 6
-2 -4
Acceleration
G UNITS
N 30 60 E 120 150
STEER
FOR
S 210 240 W 300 330
STEER
RADIO
FOR
ON ON
120 80
knots
knotswinter
50 60 70 80 90 100
knots SALTO
+
−
PWR
FNCN
SEL
VOL BATT
KNOTS
PUSH
Yaw string indication
30.0
29.929.8
I00 FEET
CALIBRATED
TO
20,000 FEET
ALT
NAV
PUSH
4 6
-2 -4
Acceleration
G UNITS
N 30 60 E 120 150
STEER
FOR
S 210 240 W 300 330
STEER
RADIO
FOR
ON ON
120 80
knots
knotswinter
50 60 70 80 90 100
knots SALTO
+
−
PWR
FNCN
SEL
VOL BATT
KNOTS
Coordinated Turn
Figure 7-38. Coordinated turn.
Turn Coordination
In a slipping turn the glider turns at a lower rate for the bank used due to yaw toward the outside of the turning flightpath.
The pilot reestablishes a coordinated turn by decreasing the bank (ailerons), increasing yaw in the direction of the turn
(rudder), or a combination of the two. [Figure 7-39]
30.0
29.929.8
I00 FEET
CALIBRATED
TO
20,000 FEET
ALT
OFF
GO
NAV
NET AVG
PULL
PUSH
HW
DIST
ALT
PUSH
4 6
-2 -4
Acceleration
G UNITS
N 30 60 E 120 150
STEER
FOR
S 210 240 W 300 330
STEER
RADIO
FOR
ON ON
120 80
knots
knotswinter
50 60 70 80 90 100
knots SALTO
+
−
PWR
FNCN
SEL
VOL BATT
KNOTS
PUSH
Yaw string indication
30.0
29.929.8
I00 FEET
CALIBRATED
TO
20,000 FEET
ALT
NAV
PUSH
4 6
-2 -4
Acceleration
G UNITS
N 30 60 E 120 150
STEER
FOR
S 210 240 W 300 330
STEER
RADIO
FOR
ON ON
120 80
knots
knotswinter
50 60 70 80 90 100
knots SALTO
+
−
PWR
FNCN
SEL
VOL BATT
KNOTS
Slipping turn: insufficient
left rudder.
Figure 7-39. Slipping turn.
In a skidding turn the glider turns at a higher rate for the bank used due to the yaw toward the inside of the turning flightpath.
Correction of a skidding turn involves a decrease in yaw (rudder), an increase in bank (aileron), or a combination of the
two. [Figure 7-40]
30.0
29.929.8
I00 FEET
CALIBRATED
TO
20,000 FEET
ALT
OFF
GO
NAV
NET AVG
PULL
PUSH
HW
DIST
ALT
PUSH
4 6
-2 -4
Acceleration
G UNITS
N 30 60 E 120 150
STEER
FOR
S 210 240 W 300 330
STEER
RADIO
FOR
ON ON
120 80
knots
knotswinter
50 60 70 80 90 100
knots SALTO
+
−
PWR
FNCN
SEL
VOL BATT
KNOTS
PUSH
Yaw string indication
30.0
29.929.8
I00 FEET
CALIBRATED
TO
20,000 FEET
ALT
NAV
PUSH
4 6
-2 -4
Acceleration
G UNITS
N 30 60 E 120 150
STEER
FOR
S 210 240 W 300 330
STEER
RADIO
FOR
ON ON
120 80
knots
knotswinter
50 60 70 80 90 100
knots SALTO
+
−
PWR
FNCN
SEL
VOL BATT
KNOTS
Skidding turn: excess rudder
applied during banked turn
Figure 7-40. Skidding turn.