Obviously there is a lot of information to process when preparing to do some tow flying. As with any flying you will do, be prepared and do your homework. Completing this section is extremely helpful and will help in many ways to make your first tows more successful, but nothing substitutes solid on-site training. Listen to your instructors carefully and make every effort to execute their commands. Just as when you are flying you are the pilot in command, the you are towing the launch director and tow tech are in control of your on-site tow training.

Some gear can be purchased ahead of time, especially if you plan to do more towing in your flying future - a good bridle and hook knife are great first purchases that will save time and any confusion with gear at the tow site.
 

It is extremely important to have a solid communication system for coordinating and executing a safe tow. When using radios, the commands should be distinctive and not easily confused with other commands. “GO” and “NO” can sound alike and should not be used. “LAUNCH” and “ABORT” would be more appropriate. All members of the tow team should agree on these commands before towing. There are some recommended radio commands:

Take up slack - “More..More..More..” 

Stop the tow - “ABORT! ABORT! ABORT!” 

Ready to launch - “LAUNCHING!” 

Increase tow tension - “More..More..More” 

Decrease tow tension - “Less Tension..Less Tension..Less Tension..” Tow Director likes flight path - “Yes..Yes..Yes” 

Pilot ready to release - “RELEASING!” 

Tow-Op ready to end tow - “RELEASE..RELEASE..RELEASE”

The Launch Director or Tow-Op may issue additional commands like “LEFT” or “RIGHT” to direct the pilot to follow the tow line and avoid lockout. It may also be helpful to use a number scale during the tow. Before towing let the Tow-Op or Launch Director know what climb rate you would like. As you are climbing call out “1” for 100 ft/min, “2” for 200 ft/min, etc. Be careful when you get to “4”! It sounds like “more”. Use “4 hundred” instead. The number scale will help the Tow-Op provide a more comfortable and smoother tow.

Visual signals may be used if radios are unreliable or unavailable. There are some recommended visual signals:

Take up slack - Extend one leg out to the side and back to center.
Ready to launch - Bend forward at waist once. 

Increase tension - Flap elbows or make a running motion with feet.
Decrease tension - Spread legs to the sides, back to center, repeat.
Pilot ready to release - Spread legs and hold them there.
Tow-Op ready to end tow - Significantly reduce towline tension.

 

Over-towing occurs when too much tow force or control input has been applied to the glider. It may also be caused by thermal activity during the tow. It is essentially a deep stall induced by an excessive angle of attack. Using large amounts of brake close to the ground (where over tow is more likely due to the tow force angle) can lead to an over-tow situation without the altitude required to recover.
 

Lockout occurs when the flight path of the paraglider diverges from the towline force by 45o or more or if the glider rolls past 45o from level flight. Lockout will occur if the Tow-Op applies too much force on the tow line, the pilot uses too much brake during the tow, or the pilot fails to follow the tow line. Typically a glider will begin to rapidly diverge from the tow line direction and point nose down at the ground. Once lockout has occurred the glider will be difficult or impossible to steer and if allowed to continue, will result in injury. To prevent lockout or fix it once it has happened, the Tow-Op should reduce the tension on the line, or you should release from the tow line. When the Tow-Op reduces the tow force you will be allowed to swing back underneath the glider and steer back toward the tow line to continue the tow. If the Tow-Op fails to reduce the tow force you MUST release immediately. Because of the high tow forces needed to maintain a lockout you should be prepared to manage the surges after release. If both the above methods fail, deploying the reserve will slow the descent and avoid injury.
 

Step-towing is a technique used to gain altitude beyond what the tow rig would otherwise be able to tow a pilot to in a given area. Once you have reached the normal release point you will turn and run downwind with the line which is paid-out by the Tow-Op. At some point you will turn back toward the line and be towed again to a new altitude. There are some added risks with this method and should not be used by inexperienced pilots or Tow-Ops. If the tow line snags on the ground or a pulley, the spool locks up, or the Tow-Op doesn’t coordinate the turn causing the line to tension while you are on the downwind leg, the result will be the same as overflying the tow rig.
 

Once you have performed your pre-flight, connected to the tow line, and the Launch Director has given you the OK, you are ready to launch. When performing a forward launch the Launch Director will direct the Tow-Op to gently add tension to the line. You should brace yourself against the pull of the line to avoid disturbing the canopy until you are ready to launch. When you are ready, begin running forward, bringing the canopy up overhead. At the same time the Tow-Op gradually begins reeling in the line until normal tow tension is reached and you climb at an appropriate rate. If you choose to perform a reverse launch there should be enough slack on the line to permit you to move toward the glider without tensioning the line. Once you have the glider overhead and stable, in the forward position, the Tow-Op can be directed to add tension on the line and pull you aloft. Remember to keep your feet down for at least the first 50’ feet of altitude. If the tow pressure suddenly decreases or the weak link breaks you should be prepared to land on your feet.

When airborne you must concentrate on following the line to avoid lockout. If the tow runway is directly into the wind, following the line will be fairly easy as the tow line will remain fairly straight. However, if there is a crosswind or you strayed off course early in the flight there may be a large “bow” in the line. You must steer your glider gently toward the bow regardless of where the tow rig or runway is. The line should be perpendicular to your glider. With your feet together and in front of you the line should lay loosely between your feet. Think of it as a gun sight. If it is pulling to either side of straight ahead or pushing on one foot more than the other, you should correct your course appropriately with as much weight-shift as possible and only as much brake as you need. Control inputs on tow will be delayed but have a greater effect when the glider does react. When you are perfectly aligned with the line you will feel the “neutral point” where your glider needs no input to fly straight. Maintaining at least a light pressure on the brakes will help you find and feel the neutral point. Remember to be gentle and progressive with your control inputs. It is easy to overshoot the line and end up in a turn to the opposite direction resulting in a wobbly ride. If the Tow-Op sees that you are approaching lockout they will immediately decrease the tension on the tow line to help you then reapply tension when you are following the line.

While the Tow-Op controls most of the tension on the line, you may fine tune the tension and your climb rate by adjusting your brake pressure. Adding VERY SLIGHT brake pressure slowly will increase your climb rate, while decreasing your brake pressure will slow your climb rate. If the Tow-Op suddenly applies more tension, or you hit a thermal, your angle of attack may increase quickly and you should decrease your brake pressure immediately. Climb rates of 700-800 ft/min are acceptable.

Once you are at an appropriate altitude and following the tow line properly you may get comfortable in your harness. The same rules apply as when foot launching. Getting comfortable is a low priority, maintaining directional control is a high priority! Using a foot stirrup is always the most effective and preferable but is not available on all harnesses. The one handed method may still be used during a tow though it is extremely important that you are not distracted by getting seated and inadvertently steer your glider off course. Use the hand opposite the reserve handle and bridle release to slide yourself into the harness while lifting your knees to your chest. If you are drifting left, push your control hand left. If you are drifting right, push your control hand right to correct your course. Never let go of your brakes and/or grab the risers to to help you get into the harness. Once you are comfortable, cross your legs at the ankles or put your feet together.

When you reach maximum height from the tow, see significant slack on the line, enter a thermal, receive a release command from the Tow-Op, or if anything looks wrong you should release. If you are still under full tow force on an uneventful tow, alert the tow operator that you are about to release. Releasing under full tow pressure will result in a surge, and the bridles may snap back toward you. You will place both brakes in the hand opposite from your release handle and stick your hand to the center of your forehead. With the other hand, reach forward and pull the release handle. If there is still tension on the line the glider may surge slightly. The line should release from your bridles and free you from the tow. If the release mechanism fails to release the line due to lack of tension you may have to grip the line between your feet and push it away from you while pulling the release handle. If there is any other sort of malfunction it may be necessary to use a hook knife to cut the weak link or release both brakes and fix the malfunction. It is important that during the release procedure you not fly beyond the tow rig or pulley or drift off course.

During the tow there is a significant amount of force on the tow line and weak link. Old or worn lines may spontaneously break and cause a surge. You should be prepared at all times to deal with a sudden and strong surge, especially during the first third of the tow. If the line breaks you may be dragging a significant length of it behind you. It is important that you release the line from your bridles before it becomes snagged on a ground object. It may feel like a weak link break and you won’t realize that you are dragging line. Always check your connection after a line failure to make sure you are clear. If the line has become snagged on a ground object you must release immediately, use a hook knife, or fly circles (or figure-8’s) over one spot to avoid putting tension on the line. Flying circles will stack the line over the snagged object, allowing you to descend without tensioning the line.

 

In order to safely perform a tow launch you should understand some risks, and basic forces that will be exerted on you during the tow. The tow system is designed to apply a relatively narrow pressure range to the glider. Too little pressure and the glider descends. Too much and over-tow or lockout can occur. When the system is working properly the tow operator is able to adjust the tow forces such that the glider gains altitude, without over-towing. Typical pressure for a pilot new to towing is 60-75% of their flying weight. However, there are some situations, depending on the type of tow system used, that can change the tow forces unexpectedly. Talking with the tow operator about your preferences before performing a towed launch can help avoid misunderstandings about tow pressure.

Line dig is the most common and occurs when the line on a pay-out winch has become stuck either between other lines or on part of the tow rig and suddenly stops paying out. The tow system instantly becomes a static tow and tow forces can escalate quickly depending on the speed of the tow vehicle. Use of a properly sized weak link will prevent anything more dangerous than a weak link break from occurring.

As line is spooled onto the drum during a pay-in tow the spool diameter increases and, at a constant RPM, the tow force exerted on the glider will decrease. During a pay-out tow, where the spool diameter decreases, the line force will increase. The tow operator should be aware of the trend and can adjust for either scenario.

When towing in a cross wind without the tow rig properly aligned with the wind the forces exerted on a glider can be higher than if towing directly into the wind. This is because the towing force is directed across the axle rather than at 90o. Part of the resistance from the glider is now fighting against the sideways pull of the tow line. Using a fairlead at the tow rig will allow the line to be presented at a 90o angle to the axle/spool at all times.

During any tow the force exerted by the tow line will pull the pilot ahead of the glider. This results in an increased angle of attack, and an increased wing loading especially at higher line angles. Most paragliders do not turn well at high angles of attack which may prompt the pilot to use more brake input to perform a turn. Because the glider is already at a high angle of attack, more brake may stall the glider. The increased wing loading has also increased your stall speed. Increased stall speed + increased angle of attack + brake is a dangerous combination. For this reason speed assists and light brake inputs are encouraged.

 

Your first tows will probably be forward launches as it is the easier to see the tow line and there are fewer chances for stepping on it. The same rules apply to a forward on a tow line as a forward off a hill. The glider should be thoroughly checked for line tangles and laid out in a clean, curved shape so that the center cells inflate first. As the Tow-Op increases the tow force you should be prepared to run and follow the tow line. Remember that you will still have to center yourself under the glider while being pulled by the tow line. This may require stepping to the side and steering the glider with the brakes.

In stronger winds, you may choose to do a reverse inflation. The difference be- tween a reverse inflation and a forward on a tow line is that during a reverse you must ALWAYS turn away from your reserve handle, and the tow line must always be routed to the opposite side as your reserve to avoid tangles or accidental deployments. In addition you should never build tension on the line while performing a reverse launch. In conditions appropriate for a reverse the pilot is often required to step toward the glider and away from the tow rig. If the line is already tight, stepping toward the glider will add additional tension to the line and may be sufficient to lift the pilot off the ground before they are ready. An additional risk during a reverse launch is stepping on or over the line before tension has been applied. When the Tow-Op does apply tension the line may catch the pilot behind one or both feet making it difficult to run and pulling the pilot aloft unevenly. When doing a reverse launch make sure the line is clear of your launch path.
 

As with any launch you should always have a pre-flight checklist. Remember that the pre-flight is always the pilots responsibility! The standard checklist can be modified for flights originating with a tow. R1234-Big-Huge-STARVE.

Reserve Parachute - Check the handle and pins. Make sure everything is secure.

1. Helmet Strap - Check to make sure it is securely fastened. You should never attach yourself to a glider without your helmet on.

2. Carabiners - Check to make sure that the gates are closed and locked. 


3. Harness Buckles - Give them a tug to make sure they are securely buckled.

4. Corners - From the two A risers and two D risers follow the lines up to the canopy to make sure they are clear and there no snags, knots, etc.

Bridles - Check that they are connected to your carabiners properly, attached to the weak-link correctly and will release cleanly.

Hook Knife - Make sure you have a hook knife within reach and easily ex- tractable from its case. You should be able to reach the weak-link with it! They are mandatory on ALL tow flights.

Stirrup & Speed System - Check to see that your speed system is properly attached, routed, and clear of your reserve parachute handle and tow bridles. If you have a foot stirrup check to see that it is clear of your speed system and will be easily accessible after launch. This usually means putting one leg through/behind the stirrup bar.

Top & Turn - Make sure the correct riser is on top for the direction you will be turning after a reverse launch.

Airspace - Check the surrounding airspace to avoid collisions during launch.

Radio - Check for the correct frequency and that you can transmit and receive.

V-shape - Check for V’s between brake lines and rear risers to avoid brake line twists.

Even pressure - Ensure that tension on A-lines are even when doing a forward inflation.

The Launch Director can assist you when preparing for launch, especially when it comes to testing the release mechanism.

 

Since towing requires extra equipment you should know how to use the pieces that are connected to you, the pilot, and be aware of the type of tow system that is being used.

Bridles

Tow bridles are rope or webbing that connect your two main carabiners to the tow-line and allow you to disconnect when necessary. There are many different types of bridles used to tow paragliders aloft, but the two most common are 1-piece and 2-piece. 1-piece bridles are attached together at the release mechanism end and when released from the line, do not fall to each side of your harness. This reduces the risk of tangling with your reserve handle and requires no extra action after releasing from the tow-line. However, they do make it more difficult to get into and out of your harness so they are not recommended for flying over water. 2-piece bridles fall apart at the release mechanism end after releasing from the tow- line. After releasing you will need to place the two pieces in your lap to avoid interference with your reserve handle. 


Both bridle types, when connected to the line, form a “V” between the tow line, and your two carabiners. The release mechanism is located at the farthest end from you, and the release handle should be easily within reach. The other ends should always be connected to the top of your carabiners with webbing loops. NEVER attach the bridles in such a way that it applies force to the stitching of your harness or in which they could cross-load the carabiners during flight. There shouldn’t be any hard or heavy parts on the bridles. In the event of a weak link break or line failure, the bridles could snap back into the pilot and heavy objects could lead to injury. The weak link, which sits between the line and the bridles, should be reachable with a hook knife.

Some bridles have “tow-assists” or “speed-assists” which connect to your speed system and speed the glider up during the launch and tow. They help to mediate the increased angle of attack during a tow and in all but a very few cases are considered much safer than towing without a speed assist. If the glider being towed has any tendency to hang back while ground handling, is old, or is lightly loaded, a speed assist system may be required for a safe tow. Heavily loaded gliders, or fast, performance gliders may not need a tow-assist. Contacting the wings manufacturer for a recommendation may be in order.

The release mechanism, which will release the tow line from your bridles, should be simple, reliable, and work properly with no tow force, and extremely high tow forces. The most common mechanism is a rope 3-ring-circus which has been adapted from skydiving releases. They are light, reliable, and distribute the load throughout the release allowing it to work under very high forces. It is extremely important that you are familiar with the type of release on your bridles, and what mistakes you can make when connecting it. In the case of a rope 3-ring-circus the longest loop should ALWAYS be the one passed through the weak link. The release trigger or handle should be reachable by either hand when the tow-line is pulled to 60o either side of straight- ahead ahead, 90o down and 180o down and back.

The release handle should be on the opposite side of your harness from your reserve handle for consistency. You will have to fly one handed (both brakes in one hand) during the release and you should be in the habit of using the same hand to release, and get into the harness if it is not fitted with a stirrup.

Weak Links

Weak Links or safety links are required on every tow and should be rated to a strength of no more than 150% of the total pilot weight. They are usually connected between the tow line and the bridles and stay connected to the pilots bridle when the pilot releases. By keeping the weak link on the bridles each pilot keeps the weak link that is properly sized for them, and it prevents abrasion wear on the tow bridles. When the force on the pilot is too great the weak link is designed to break, preventing excessive forces on the canopy. They are NOT designed to prevent lockout! Weak links that are too weak may break while the pilot is still close to the ground leading to a surge where the pilot swings forward or backward into the ground. Weak links should be changed regularly to ensure that they are still rated for the proper strength and don’t break prematurely.

Hook Knife & Extra Reserve

If something goes wrong with the tow, a hook knife can potentially save your life. All pilots on tow MUST have a hook knife. It should be sharp and unused, but one that is made of steel and hasn't been used much or is in very good condition will do the trick. If the tow line fails to release from the bridles for any reason, a hook knife may help you free yourself. Be sure to attach the knife to your harness in such a way that you can easily release it from its case with one hand. Many people make the mistake of attaching it without this thought and find themselves unable to get the knife with one hand. The tow-tech operating the winch will also have at least one hook knife (most good tech operators will have 2 0r 3) within easy reach in case an emergency situation presents itself.

In addition to having a good hook knife, many SIV instructors are making a second reserve part of their mandatory gear for anyone on tow. As per USHPA regulations, every pilot must fly with a reserve, but having a second reserve in a belly mount container can add an additional measure of safety especially if the pilot is training in advanced maneuvers. There are a few videos that show how an situation where the main glider and reserve become entangled and the second reserve saved the pilot’s life.

Tow Lines

Various types of line or rope can be used for towing. The most popular types are Nylon and SpectraTM because of their durability and strength. Nylon line has a much greater stretch than SpectraTM and can dampen oscillations during a tow. Generally it results in a smoother tow but is not as strong. Spectra lines have less drag and will result in higher tows but is more expensive and not as forgiving.

Tow Systems

There are 3 different types of tow systems commonly in use for paragliders. The static line, stationary winch, and pay-out winch. All of them must be able to limit or reduce the tow force, zero the force (hook knife), and be able to gradually increase and decrease the tow force. Under no circumstances should the line be tied to the spool in such a way that if the line were pulled to the end, it wouldn’t automatically separate from the spool. A reversing pulley may be used in some circumstances and should be able to swivel without binding the tow line between the wheel and block. Typically the tow-lines are Spectra/Dyneema which is light and does not stretch. However, for a smoother tow other lines may be used which, while heavier, will stretch and provide a cushion against bumps in the air or tow surface.

Static line systems use a fixed length of line attached to a moving vehicle and requires an extremely skilled Tow-Op. The Tow-Op monitors the tension with a pressure gauge and adjusts the vehicle speed accordingly. It requires a smooth road or body of water. Static line towing is NOT recommended for paragliders.

Stationary winches (Pay-in or Scooter tow) remain at one end of the field or road and spool the line onto a drum to generate tension. The Tow-Op is able to adjust the tension with a hydraulic pump or with the engine throttle during the tow and can pay-out line if necessary. This is a popular method for rough fields and when using pulleys. The altitude attainable is less than a pay-out winch on a moving vehicle but requires less operating distance.

Pay-out winches are mounted on moving vehicles and release line from the drum as the tow progresses. The pressure is moderated by the speed of the vehicle and the hydraulics of the winch itself. It’s the most popular method for maneuvers courses where the winch is mounted on a boat that can travel in large circles around the lake, towing the pilot to altitudes sufficient for maneuvers. Payout winches typically have a “rewind” system for reeling the line back in after a tow.