Στο βιβλίο του Dennis Pagen "Towing
Aloft", θα βρείτε πολλά και ενδιαφέροντα για το θέμα. Παραθέτουμε στα
αγγλικά ένα μέρος του βιβλίου.
Tow Phase: Launch process
1. Take up slack (launch observer signals).
Tow Phase: Climbout
1. As the glider climbs, maintain light tow pressures to above
30 m (100 ft).
Tow Phase: Release and Retrieval
1. When the pilot signals or you reach the predetermined
tow termination point, reduce pressure for release.
Paraglider Towing Problems
Here we cover what can go wrong and what the crew should look for to determine a course of action. Not every paraglider tow comes off in a picture perfect manner. Here we will look at minor and major mishaps to see how to avoid them or minimize their danger. From Dave Broyles comes a description of what he calls benign launch failures. They are failures in so much as they result in a delayed or aborted tow, but they don't usually lead to an accident with an alert tow crew. In fact, these benign failures are actually successes of the towing procedure if they lead to a safe termination of the tow.
Here is a list of typical problems:
The canopy fails to come fully overhead.
All of these events happen during typical tow operations, especially when the pilot is inexperienced or the conditions
are challenging. In all cases, termination or delay of the tow is
the proper procedure. If the canopy is not perfectly inflated or
positioned as in the first four cases, the launch observer should
command "abort, abort" and visually issue the stop signal. The
winch or vehicle crew should gently reduce towline tensions and
Dealing with Paragliding Emergencies
The common emergency that occurs when towing paragliders is a lockout. Other emergencies include continuous application of too much brake control, collapse under tow and release failure. In the first three cases, the solution is the same: reduce tow pressure to let the glider regain normal flying status.
In the case of lockouts, the tow crew should carefully monitor the canopy for alignment with the towline. If the pilot does not quickly correct a misaligned canopy or if the pilot is below 30 m (100ft), the tow operator should reduce the tow force continuously until the glider responds in the correct direction. Normally, a reduction in the tow force will signal the pilot to pay more attention to the canopy heading.
If the pilot is using too much brakes, backing off on tow
tension can help bring the canopy above him. The tow crew should monitor the
glider for attitude (nose-up position) and pilot position. If the rear of the
canopy appears to be less than 3/4 of its normal height above the pilot's head,
or wider than a narrow crescent, then either the tow force is too high or the
pilot has added brakes, or both may have occured. When viewed from the side, the
canopy should not trail back much beyond 45 degrees from the vertical.
The tow crew must be especially alert in the event of a release failure. The pilot may be able to communicate verbally that the problem exists, but an alert tow crew should be intently watching the end phase of the tow to see if the pilot stays on line beyond the termination of the tow (the winch or vehicle stops). If so, immediate reduction of tow force is necessary which may include cutting the towline. The tow crew should understand all emergency procedures so they can anticipate what the pilot will do in various emergencies. Stop the tow if things go wrong. Aborted tows slow down the entire operation, but not nearly as much as an accident!