Introduction
In the early days of soaring, a crew might launch a glider from the top of a hill using a bungee cord. With the tail of the
glider tied down, the ground crew would attach the center of a bungee cord to a hook on the nose of the glider. Members
of the ground crew stretched the separate ends of the bungee cord ahead, into the wind, and offset from the glider. With
sufficient tension on the bungee cord and upon release of the tail tie-down, the glider would accelerate as if launched from
a slingshot.
As gliders got larger, pilots looked for better ways to launch. Enthusiasts began using cars to pull gliders. Over time, powered
winches and airplane towing became preferred launching methods. This chapter discusses glider launch techniques and
procedures as well as takeoff procedures, traffic patterns, flight maneuvers, and landing and recovery procedures.
Glider pilots should understand risks associated with the large wingspan of a glider and ground operations. The wings can
strike runway lights and other obstructions near the runway during reposition, takeoff, or landing. Impact with a wingtip
could lead to ground loops during takeoff or landing. A cartwheel could occur if a wingtip strikes the ground before the
glider touches down, leading to extensive damage and serious injury. Training, pilot proficiency, hazard consideration, and
risk mitigation before and during flight reduce the likelihood of these undesirable events.
Aerotow Takeoff Procedures
Signals
Visual signals enhance communication and coordination between the glider pilot, the pilot of the towing aircraft, and the
ground crew.
Prelaunch Signals
Aerotow prelaunch signals facilitate communication between pilots and launch crewmembers/wing runners when preparing
for the launch. Figure 7-1 illustrates these hand signals. The raise wingtip to level position is given by the pilot.
Chapter 7: Launch, Flight Maneuvers,
Landing, & Recovery Procedures
Check controls
Open towhook
Close towhook
Raise wingtip to
level position
Take up slack
Hold
Begin takeoff
Stop operation immediately
Release towline or cut towline now
Stop
Thumb moves through circle
Arm moves slowly
back and forth
through arc
Arms straight out and held steady
Arm makes rapid circles
Waves arms Draws arm across throat
Figure 7-1. Aerotow prelaunch signals.
Inflight Signals
When airborne, pilots use the flight controls to create visual signals that allow the tow pilot and the glider pilot to
communicate. The signals divide into two types: those from the tow pilot to the glider pilot and signals from the glider
pilot to the tow pilot. Figure 7-2 depicts these signals.
Decrease tow airspeed
Glider yaws repeatedly
Towplane please turn left
Glider pulls towplane tail to right
Towplane please turn right
Glider pulls towplane tail to left
Increase tow airspeed
Glider rocks wings repeatedly
Glider: Release immediately
Towplane rocks wings
Something is wrong with glider.
Close air brakes. (Towplane
fans rudder.)
Figure 7-2. Inflight aerotow visual signals.
The tow pilot could use the aerotow signals shown in the two panels on the left side of figure 7-2 when close to the ground.
The glider pilot should know how to differentiate between these signals to avoid an unnecessary release close to the
ground. Even with two-way radio in both aircraft, radio communications could distract either pilot when operating near the
ground and could increase risk of loss of control.
The two green panels of the top row of figure 7-2 illustrate how a glider pilot requests a turn. Since large or abrupt lateral
offset has the potential to interfere with tow-plane control, glider pilots should only use lateral offset signals as depicted
in at or above 1,000 feet AGL.
The two green panels of the bottom row of figure 7-2 illustrate how a glider signals for a change in speed when at or above
1,000 feet AGL. The glider pilot yaws repeatedly or rocks the wings as depicted, and the force on tow line oscillates and
causes a series of small accelerations and decelerations. Signaling in this manner should get the attention of the tow pilot
who then can look back and interpret the signal.
Takeoff Procedures & Techniques
Takeoffs benefit from a crewmember on the ground who can scan for traffic and provide general assistance during the
takeoff. An assisted takeoff includes a crewmember or wing runner who maintains the glider wing in a level position as the
glider begins its takeoff roll. An unassisted takeoff does not include a wing runner or other ground crew. Glider and tow
pilots should only perform an unassisted launch if trained on the procedure and if conditions allow for a safe unassisted
takeoff. An unfamiliar glider or lack of proficiency adds the risk of this type of takeoff.
Prior to takeoff, the tow pilot and glider pilot should agree on a plan for the aerotow. The glider pilot should also ensure
the launch crewmember has sufficient knowledge of the plan. Some items to consider include the intended ground path,
pattern clearing procedures, and glider configuration checks (spoilers closed, tailwheel dolly removed, canopy secured).
Takeoffs normally occur into the wind.
Connecting the tow line to a glider in preparation for takeoff should only occur with the glider pilot aboard and ready for
flight. The launch crewmember presents the tow rope end to the pilot so the pilot can ensure it is in good conditions and
with the correct ring and weak leak, if required. When the required checklists have been completed with both the glider
and towplane ready for takeoff, the launch crewmember/wing runner starts to hook the towline to the glider. If the pilot
exits the glider for any reason, the pilot or launch crewmember should disconnect the towline to prevent accidental tow of
an unoccupied glider.
Normal Assisted Takeoff
A deliberate tow rope hookup should occur, which includes a check of the release mechanism for proper operation. The
launch crewmember should apply tension to the tow line and signal the glider pilot to activate the release. The launch
crewmember should verify that the release works properly and communicate that information to the glider pilot. With the
tow line again hooked up to the glider, the launch crewmember moves to the wingtip on the ground and clears both the
takeoff and landing areas.
When the glider pilot signals the launch crewmember at the wingtip to lift the wing, that crewmember picks up and holds
the wing in a level position and signals the tow pilot to “take up slack” in the tow line. With the slack out of the tow line,
the glider pilot signals ready for takeoff by wagging the rudder, and the crewmember simultaneously signals the tow pilot
for takeoff. If using a radio, the glider pilot could indicate the takeoff signal to the tow pilot by stating, “Canopy locked
and ready for takeoff.”
As the aerotow begins and the glider accelerates, the launch crewmember runs alongside the glider, holding the wing in
a level attitude until the glider pilot gains roll control or the speed of the glider exceeds the crewmember's safe running
speed. An increase in resistance to aileron movement indicates aileron effectiveness. Holding the wings level with the
ailerons may require full deflection of the flight controls until sufficient airspeed increases effectiveness of the controls.
Risk of collision with runway lights, signage, and other obstructions alongside the runway during the takeoff roll increases
due to the combination of long wings and short landing gear when compared to airplanes. The pilot can mitigate this risk
by steering the glider solely with the rudder so as not to have one wing low. [Figure 7-3]
Crab into the wind to track the
runway centerline until clear of
obstacles and terrain features
Ground track
WIND
Figure 7-3. Tracking the runway centerline.
When the glider achieves lift-off speed, the glider pilot should maintain the glider at a low altitude of 2 to 4 feet—the exact
altitude depends on the specific glider. As the glider and tow plane accelerate, the glider pilot should maintain altitude by
applying stick pressure, as necessary. If the glider climbs above the towplane’s tail
during the takeoff, tension on the towline pulls up on the towplane tail and could force the towplane’s propeller into the
runway surface. Once lift-off occurs and since lateral deviation can force the towplane off the runway, the glider pilot can
use coordinated aileron and rudder to remain directly behind the tail of the towplane.
During most takeoffs, the glider achieves flying airspeed before the towplane. In this case and once the towplane lifts off, it
accelerates in ground effect to the desired climb airspeed, and the climb begins for both the towplane and glider. However,
a glider loaded with ballast might not achieve liftoff airspeed before the towplane. In this situation, the towplane should
remain in ground effect until the glider becomes airborne.
Unassisted Takeoff
The unassisted takeoff begins with the glider positioned slightly off the runway heading (runway centerline) by
approximately 10–20° with one wing on the ground. If the glider is canted to the right, then the left wing should rest on the
ground. If canted to the left, the right wing should rest on the ground. When ready for takeoff, the glider pilot advises the
tow pilot either by radio or by signaling the tow pilot with the “ready for takeoff” rudder waggle signal. As the towplane
accelerates, the wing on the ground accelerates at a slower rate due to the increased drag due to the ground contact. This
imparts a yawing motion that will help straighten out the glider. The pilot should use rudder to raise the lower wing until
sufficient speed is obtained to allow aileron control of the bank angle. If the glider begins the takeoff roll aligned with the
towplane during the takeoff, the wing on the ground tends to drag and severe swerving or a ground loop becomes more
likely.
Crosswind Takeoff
Most gliders have a crosswind limit up to approximately 10–12 knots. Pilots should refer to the Glider Flight Manual/
Pilot’s Operating Handbook (GFM/POH) for model specific information.
Crosswind takeoff procedures compensate for the following:
1. The glider tends to weathervane into the crosswind with the weight on the main wheel.
2. After lift-off, the glider tends to drift off the runway centerline with the crosswind.
Assisted
Prior to takeoff, the glider pilot should direct the launch crewmember to hold the upwind wing slightly low during the
initial takeoff roll. In a crosswind, the pilot should hold full aileron into the wind as the takeoff roll begins. The pilot
maintains this control position while the glider accelerates until the ailerons become effective. At the same time, the pilot
uses downwind rudder to maintain a straight takeoff path and offset any tendency to weathervane while on the ground.
[Figure 7-4] Note that takeoff using a CG hook makes the glider more sensitive to crosswind forces as there is no force
from the tow line acting to keep the nose of the glider aligned with the direction of motion.
Full downwind rudder deflection to start crosswind takeoff roll
WIND
WIND
Upwind wing slightly lower than downwind wing
Figure 7-4. Crosswind correction for takeoff.
As the glider’s forward speed increases, the crosswind becomes more of a relative headwind, and the pilot reduces the
application of aileron into the wind. However, the pilot maintains sufficient aileron pressure throughout the takeoff roll to
prevent the crosswind from raising the upwind wing.
If the upwind wing rises and exposes more wing surface to the crosswind, a skipping action or series of small bounces may
result as the glider begins to fly and then settles back onto the runway. This side skipping imposes side loads on the landing
gear. If the downwind wingtip touches the ground, the resulting friction may cause the glider to yaw in the direction of the
dragging wingtip, which could lead to a loss of directional control and runway departure.
While on the runway during takeoff, the glider pilot uses rudder to control direction and alignment behind the towing
aircraft. The pilot should avoid yawing back and forth behind the towplane, as this affects the ability of the tow pilot to
maintain control. If glider controllability becomes a problem, the glider pilot should release and stop the glider on the
remaining runway. In this case as the glider slows, the crosswind may cause the glider to weathervane.
After becoming airborne, but before the towplane lifts off, the glider pilot should maintain the crosswind correction to
remain behind the towplane. Once the towplane becomes airborne and is clear of obstacles, the glider pilot repositions as
needed to align behind the towplane.
Unassisted
Experienced pilots may consider using an unassisted crosswind launch procedure. An unassisted crosswind takeoff
uses different wing positioning and glider alignment. The crosswind strikes the fuselage of the glider, tending to push it
downwind, making it necessary to position the glider on the upwind side of the runway. If unable to offset, the towplane
pilot may angle into the wind to reduce the crosswind component for the glider.
The glider should rest offset on the runway with the downwind wing on the ground and the glider angled approximately
20–30° into the wind. [ Figure 7-5] As in a normal unassisted takeoff, the drag on the downwind wing imparts a yawing
moment that swings the upwind wing forward at a faster rate than the downwind wing, aiding the pilot in leveling the
wings. If the pilot begins the takeoff run with the downwind wing on the ground, a ground loop may result since the
downwind wing will drag along the ground. The pilot should execute crosswind takeoff procedures as described above
once the upwind wing rises and maintain a normal position directly behind the towplane.
20°–30°
WIND
Figure 7-5. When setting up for a crosswind takeoff, the glider should start on the upwind side of the runway.
Pilot Induced Oscillations (PIOs) During Launch
During the first moments of the takeoff roll, as airflow begins to impact the control surfaces, it takes considerable
displacement of the flight controls to affect the glider’s flightpath. The pilot also experiences a higher control lag time
due to reduced control effectiveness at low speed. As the glider accelerates, aerodynamic response improves, lag time
decreases, and PIOs become less likely.
Several pilot techniques reduce the likelihood and severity of PIOs during aerotow launch. A pilot should not attempt
to lift off until the glider responds sufficiently to aerodynamic control. Just after the moment of lift-off, the pilot should
bring the glider to two to four feet above the runway to prevent ground contact from any minor excursion in pitch attitude.
[Figure 7-6]
Premature takeoff resulting from mismanagement of elevator trim setting or wing flap position setting. Low airspeed
at lift-off results in sluggish response to elevator. Startled pilot overcontrols the elevator and PIOs result.
Figure 7-6. Premature takeoffs and PIOs.
Improper Elevator Trim Setting and PIOs
Gliders with an aerodynamic elevator trim tab or an anti-servo tab on the elevator may experience more challenging control
issues when improperly trimmed. Pilots find that a simple spring-system elevator trim tends to help prevent PIOs, but they
can still occur.
Improper Wing Flap Setting and PIOs
With an incorrect positive flap setting, the glider may lift off the runway prematurely. In response, the pilot exerts forward
pressure on the controls and exerts an increasing nose-down force on the glider. When the glider eventually pitches down,
the pilot may exert considerable back pressure on the stick to arrest the descent. A cycle of PIOs could result, which could
lead to hard contact with the runway surface, glider damage, and personal injury.
An incorrect negative flap setting decreases wing camber and wing lift, and the glider may remain on the runway even
after the tow plane lifts off and begins to climb out. The pilot may exert significant back pressure on the control stick to
lift off, and ballooning may occur as the elevator becomes more effective. A series of PIOs may result, which could require
termination of the tow to prevent ground contact or tow plane loss of control.
Gust Induced Oscillations
Gusty headwinds may induce pitch oscillations due to changes in the speed of the airflow over the elevator while crosswind
gusts can induce yaw and roll oscillations. In gusty crosswinds, the effects on glider control change rapidly depending on
the speed and angle of the crosswind component.
Nearby obstacles, such as hangars, trees, or hills and ridges can affect low altitude winds, particularly on the downwind
side of the obstruction. In general, an upwind obstacle induces additional turbulence and gustiness in the wind. Pilots may
encounter these conditions from the surface to an altitude of 300 feet or more. If flying in these conditions, the pilot should
use a faster-than-normal speed prior to lift-off.
The additional speed increases the responsiveness of the controls, simplifies correcting for turbulence and gusts, and
provides a measure of protection against PIOs. The added speed also provides a safety margin above the stall speed since
variations in the headwind component affect airspeed.