Glider, having risen too high above towplane,
dives toward towplane, inducing slack towline.
Figure 8-8. One method of generating tow line slack.
When the towplane precedes the glider into an updraft, the glider pilot perceives the towplane as climbing faster and higher
than the glider. Then, as the glider enters the updraft, it climbs higher and faster than the towplane did. As a result, the
glider pilot pitches the glider over to regain the proper tow altitude, gains airspeed more quickly than the towplane, and
creates a slack tow line.
A glider pilot should initiate slack tow line recovery procedures as soon possible by increasing drag. For example, the glider
pilot may slip back into alignment with the towplane. If slipping motion fails to reduce the slack sufficiently, careful use
of spoilers/dive brakes can decelerate the glider and take up the slack. As the tow line tightens and the tow stabilizes, the
glider pilot removes the extra drag and resumes the desired aerotow position. The glider pilot should immediately release
from the aerotow if the slack in the tow line becomes excessive or gets beyond the pilot’s capability to recover safely.
Common errors regarding a slack line include:
• Failure to take corrective action at the first indication of a slack line.
• Improper procedure to correct slack line causing excessive stress on the tow line, towplane, and the glider.
• Failure to decrease drag as tow line slack decreases.
Ground Launch Abnormal & Emergency Procedures
Abnormal Procedures
The launch equipment operator manages a speed-controlled winch some distance from the glider, and the initial tow speed
and tension could vary. A tow line speed too great could exceed glider limitations while a speed too low may make liftoff
difficult, prevent further climb after liftoff, or result in stall after takeoff. The pilot should use appropriate radio calls and
augment with visual signals if necessary, to direct the launch operator to increase or decrease speed. The pilot should
release the tow line and land ahead if an abnormal situation develops.
A launch mechanism malfunction may interrupt a ground launch. A gradual deceleration in rate of climb or airspeed may
be an indication of this type of malfunction. If suspecting a launch mechanism malfunction, the glider pilot should release
and land ahead. However, a pilot might confuse an unintended opening of the spoilers with a winch malfunction if the
pilot does not notice the spoilers opening. The pilot should quickly check the status of the spoilers if performance appears
degraded during the tow.
Wind gradient (a sudden increase in windspeed with height) can have a noticeable effect on ground launches. A significant
or sudden wind gradient may increase indicated airspeed and exceed the maximum ground launch tow speed. [Figure 8-9]
When encountering a wind gradient, the pilot should push forward on the stick to reduce the tension on the tow line, which
reduces indicated airspeed. The only way for the glider to resume climb without exceeding the maximum ground launch
airspeed involves signaling the launch operator to reduce tow speed. After the reduction of towing speed, the pilot can
resume normal climb. If launching using a winch with automatic tension control, the glider pilot uses conventional pitch
changes to control airspeed and climbs at a higher rate if wind speed increases in a gradient.
Wind 20 knots
Wind 10 knots
Effect of wind gradient on airspeed
during ground launch. Pilot must
monitor airspeed indicator carefully.
Goal is to fly fast enough to maintain
a safe margin above stall speed, but
slower than maximum permitted
ground launch airspeed.
Figure 8-9. Ground launch wind gradient.
Emergency Procedures
A broken tow line may cause an emergency during a ground launch. [Figure 8-10] When a tow line failure occurs, the glider
pilot should pull the release handle, immediately lower the nose of the glider, and maintain a safe airspeed. Distinguishing
features of the ground launch include nose-high pitch attitude and a relatively low altitude for a significant portion of the
launch and climb. If a tow line break occurs and the glider pilot fails to respond promptly, the nose-high attitude of the
glider may result in a stall.
Very early break: land straight ahead. Tow vehicle, if used, should clear runway to make way for the glider.
SNAP
Airborne break: lower nose and promptly land straight ahead.SNAP
If towline is parachute equipped, avoid parachute when lowering nose after towline break or normal release.
Figure 8-10. Ground launch tow line break.
If the glider tow release mechanism fails, the pilot should fly at airspeeds no lower than best lift over drag (L/D) airspeed.
The pilot should fly over and then past the ground launch equipment. This method allows the glider tow hook back release
to activate or the tow line weak link to fail. The ground launch equipment also uses an emergency release mechanism in
the event the glider tow release fails. Winches should have a guillotine to cut the tow line, if necessary. If using a motor
vehicle for a ground launch, it should also have some form of backup release mechanism.
Self-Launch Takeoff Emergency Procedures
Prior to takeoff, the pilot should formulate emergency plans for any type of failure that might occur. Thorough knowledge
of aircraft performance data, normal takeoff and landing procedures, and emergency procedures as outlined in the GFM/
POH help bring about the successful management of any emergency.
Mismanagement of the aircraft systems through lack of knowledge may cause serious difficulty. For instance, if the spoilers
or dive brakes remain open during takeoff and climb or open inadvertently, the self-launching glider may not generate
sufficient excess power to continue climbing. Other emergency situations may include inflight fire, structural failure,
encounters with severe turbulence, wind shear, canopy failure, and inadvertent encounter with instrument meteorological
conditions (IMC).
Possible options for handling emergencies depend on altitude above the terrain, wind, and weather conditions. As a part
of preflight planning, pilots should review the effects of density altitude on glider performance, the takeoff runway length,
landing areas near the gliderport, and potential air traffic that could affect the pilot’s approach and landing decisions.
Emergency options may include landing ahead on the remaining runway, landing off field, or returning to the gliderport
to land on an available runway. The appropriate emergency procedures may be found in the GFM/POH for the specific
self-launching glider.
Spiral Dives
An excessive low-nose attitude during a steep turn may result in a significant increase in airspeed and loss in altitude,
which indicates a spiral dive. If the pilot attempts to recover from this situation by applying back elevator pressure only, the
limiting load factor may be exceeded, causing structural failure. To recover from a spiral dive, the pilot should first reduce
the angle of bank with coordinated use of the rudder and aileron, and then smoothly increase pitch to the proper attitude.
Common errors during spiral dives include:
• Failure to recognize when a spiral dive develops.
• Rough, abrupt, or uncoordinated control application during recovery.
• Improper sequence of control applications.
Spins
During a spin, the glider follows a downward corkscrew path. A spin entry may occur after an aggravated stall of one or
both wings that results in rotation around the vertical axis. As the glider rotates around the vertical axis, the outer wing
develops more lift and less drag than the inner stalled wing, creating a rolling, yawing, and pitching motion. [Figure 8-11]
The pilot may not realize that the critical angle of attack has been exceeded until the glider yaws toward the lowering wing.
Flight path
Relative wind
Figure 8-11. Autorotation of spinning glider.
Many gliders need considerable effort to enter a spin and require good judgment and technique to intentionally enter a spin.
However, these same gliders may enter a spin accidentally if the pilot mishandles the controls in turns, stalls, and flight at
minimum controllable airspeeds. This fact explains why pilots should practice stalls and develop the ability to recognize
and recover from them.
Continued practice of stall recognition and recovery helps the pilot develop an instinctive and prompt reaction to prevent
a spin. The pilot should apply immediate corrective action any time the glider approaches spin conditions, and the pilot
should immediately execute spin recovery procedures if a spin occurs.
A flight instructor may demonstrate spins and spin recovery techniques with emphasis on any special spin procedures or
techniques required for a particular glider. Before beginning any spin operations, the following items should be reviewed:
• GFM/POH limitations section, placards, or type certification data sheet, to determine if the glider is approved for
spins.
• Weight and balance limitations.
• Proper recommended entry and recovery procedures.
• Any requirements for parachutes as given in Title 14 of the Code of Federal Regulations (14 CFR) part 91.
Before any flight, and especially one with intentional spins planned, pilots should check for excess or loose items that may
affect the weight, CG, and controllability of the glider. Slack control cables (particularly rudder and elevator) could prevent
full control deflections and delay or preclude recovery in some gliders.
Prior to initiation of a spin, the pilots should check the flight area above and below the glider for other air traffic and not
spin if any conflict exists. Clearing the area may occur while slowing the glider for the spin entry. All spin training should
initiate at an altitude high enough for a completed recovery at or above 1,500 feet AGL and within gliding distance of a
landing area. The following paragraphs describe four phases of a spin.
Entry Phase
In the entry phase, the pilot provides the necessary elements for the spin. The spin demonstration entry procedure begins
much like a stall. However, as the glider approaches a stall, the pilot smoothly applies full rudder in the direction selected
for spin rotation and full back (up) elevator to the limit of travel. The pilot should maintain the ailerons in the neutral
position during the spin procedure unless the GFM/POH specifies otherwise.
Incipient Phase
The incipient phase begins as the glider stalls and rotation begins. As an incipient spin develops, the indicated airspeed
should read near or below stall airspeed. This phase can run until the spin develops fully, which may take up to two turns
for most gliders. Instructors commonly use an incipient spin for introduction to spin training and begin recovery prior to
the first of 360° of rotation. In this phase, the aerodynamic and inertial forces have not achieved a balance.
Developed Phase
The developed phase occurs when the glider’s angular rotation rate, airspeed, and vertical speed stabilize with the glider
in a nearly vertical flightpath. Equilibrium occurs in this phase as aerodynamic forces and inertial forces balance and the
attitude, angles, and self-sustaining motions about the vertical axis become constant or repetitive.
Recovery Phase
This phase may last for a quarter turn to several turns. To accomplish spin recovery, pilots should follow the manufacturer’s
recommended procedures. In the absence of the manufacturer’s recommended spin recovery procedures, pilots should
follow the following steps for general spin recovery:
1. Ailerons to neutral. Ailerons may have an adverse effect on spin recovery. Aileron control in the direction of the
spin may increase the rate of rotation and delay the recovery. Aileron control opposite the direction of the spin may
cause the down aileron to move the wing deeper into the stall and aggravate the situation. Retract flaps, if extended,
as soon as possible after spin entry.
2. Apply full opposite rudder against the rotation. Ensure full (against the stop) opposite rudder until rotation stops.
As spin rotation stops, neutralize the rudder. If not neutralized at this time, the deflected rudder may cause a yawing
effect in the opposite direction.
3. When rotation stops, apply a positive and brisk, straightforward movement of the elevator control past neutral to
recover from the stall. Slow and overly cautious control movements during spin recovery may result in the glider
continuing to spin indefinitely, even with anti-spin inputs. A brisk and positive technique, on the other hand, results
in a more positive spin recovery. Hold the controls firmly in this position until airspeed begins increasing.
4. With rotation stopped, angle of attack below the critical angle, and nose-down attitude, airspeed increases rapidly.
Make smooth pitch control input of sufficient magnitude. Pulling up aggressively may cause a second stall and spin
during the recovery. Waiting too long to pull up could lead to high airspeed and excessive G-loading.
The FAA recommends these recovery procedures for use only in the absence of the manufacturer’s procedures. Before any
pilot begins spin training, the pilot should understand any spin recovery procedures provided by the manufacturer.
The most common problems in spin recovery include pilot confusion when determining the direction of spin rotation and
whether the maneuver constitutes a spin or a spiral dive. An inclinometer does not indicate the direction of a spin. A high
or increasing airspeed indicates a spiral dive. In a spin, the airspeed reads at or below stalling speed.
Common errors when encountering/practicing spins include:
• Failure to clear area before a spin.
• Failure to establish proper configuration prior to spin entry.
• Failure to correct airspeed for spin entry.
• Failure to recognize conditions leading to a spin.
• Failure to achieve and maintain stall during spin entry.
• Improper use of controls during spin entry, rotation, or recovery.
• Disorientation during spin.
• Failure to distinguish a spiral dive from a spin.
• Excessive speed or secondary stall during spin recovery.
• Failure to recover before descent below safe altitude.
• Failure to recover with a landing area within gliding distance.
Off-Field Landing Procedures
Off-field landings may occur in the vicinity of the launching airport due to unexpected rapid weather deterioration, a
significant change in wind direction, unanticipated amounts of sinking air, disorientation, lack of situational awareness,
tow failures, and other emergencies. In these situations, a precautionary off-field landing may present less risk than an
approach back to the airport. If the pilot loses sight of the airport or if the glide back to the airport comes up short for any
reason, the attempt to return to the airport may result in damage to the glider or injury to the pilot.
A glider pilot should always be prepared for off-field landings as the absence of sufficient lift may require an off-field
landing. Even when flying in a self-launching glider, the engine or power system could fail.
The basic ingredients for a successful off-field landing include an awareness of wind direction, wind strength at the
surface, and obstacles along the approach path. The glider pilot should select suitable landing areas while airborne with
sufficient height and time to plan and perform a safe approach and landing, and then make an accurate landing to the actual
selected field.
These basic ingredients for a successful off-field landing can be summarized as follows:
• Recognizing the possibility of imminent off-field landing.
• Selecting a suitable area, then a suitable landing field within that area.
• Planning the approach with wind, obstacles, and local terrain in mind.
• Executing the approach, landing, and stopping the glider as soon as possible.
• Contacting ground crew and notifying them of the off-field landing location.
Denial represents the most common off-field landing planning failure. The pilot experiencing denial finds it easier to focus
on continuing the flight and attempting to find a way to climb back up and fly away. This false optimism leaves little or no
time to plan an off-field landing if the attempt to climb fails.
When planning an off-field landing, flying downwind offers more range and a greater area to search than flying upwind.
After selection of a landing zone, wind awareness allows the pilot to plan the orientation and direction of a landing approach
into the wind to shorten the landing roll. Pilots should visualize the wind flowing over and around the intended landing area
including how low altitude turbulence may exist in the area downwind of hills, buildings, and other obstructions.
Pilots should use a methodical approach to an off-field landing based on a set of decision heights. The pilot should select
a general landing area no lower than 2,000 feet above ground level (AGL) and select the intended landing field no lower
than 1,500 feet AGL. At 1,000 feet AGL, the pilot should commit to flying the approach and landing.
Pilots should consider safety rather than an easy retrieval as the highest priority when selecting a landing site. During an
off-field landing approach, the pilot will likely not know the precise elevation of the landing site. Since this makes the
altimeter less useful, the pilot should fly the approach and assess the progress by recognizing and maintaining the angle that
brings the glider to the intended aiming point for the landing site. When landing with a tailwind (due to slope or one-way
entry into the selected field due to terrain or obstacles), the pilot should use a shallower approach angle.
A good approach clears each visible obstacle, including clearing any poles and wires by a safe margin. From the air, wires
may not appear until right in front of the pilot, whereas towers supporting wires appear from a greater distance. The pilot
should assume that wires run between telephone poles, supporting structures, and buildings. The pilot should plan to
overfly any wires that may be present, even if not actually seeing them.
The pilot should select a field of adequate length and one with no visible slope, when possible. Any slope visible from
the air becomes steep when close to the ground. Color may assist in assessment of slope. High spots often appear lighter
in color than low spots because soil moisture tends to collect in low spots and darkens the color of the soil. If the landing
will occur on a slope, landing uphill works better than downhill. With a slight downhill grade, the glider will stay airborne
longer and experience a longer landing roll, which may result in a collision with objects at the far end of the selected field.
A pilot familiar with the colors of local seasonal vegetation can identify crops and other vegetation from the air. Tall crops
generally present more danger than low crops. Pilots should also avoid discontinuities such as lines or crop changes since
these discontinuities often indicate the presence of a fence, ditch, irrigation pipe, or some other obstacle or machinery that
could damage a glider.
The recommended approach procedure should include the following legs:
• Crosswind leg on the downwind side of the field
• Upwind leg
• Crosswind leg on the upwind side of the field
• Downwind leg
• Base leg
• Final approach