Ground Launch Abnormal and  Emergency Procedures Abnormal Procedures Emergency Procedures Figure 8-15.  Ground launch wind gradient. 20 30 40 50 60 70 80 90 20 30 40 50 60 70 80 90 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. If the glider tow release mechanism fails, the pilot should fly  at airspeeds no lower than best lift over drag (L/D) airspeed.  He or she should fly over and then past the ground launch  equipment. This method allows the glider towhook back  release to activate or the towline weak link to fail. The ground  launch equipment is also equipped with an emergency release  mechanism in the event the glider tow release fails. If a winch  is used, it is equipped with a guillotine to cut the towline.  If a motor vehicle is used as a ground launch, it should be  equipped with some form of backup release mechanism. Wind gradient (a sudden increase in windspeed with height)  can have a noticeable effect on ground launches. If the  wind gradient is significant or sudden, or both, and the  pilot maintains the same pitch attitude, indicated airspeed  increases that could exceed the maximum ground launch  tow speed could occur. The pilot must adjust the airspeed  to deal with the effect of the gradient. When encountering  a wind gradient, the pilot should push forward on the stick  to reduce the indicated airspeed.  [Figure 8-15]  The only  way for the glider to resume climb without exceeding the  maximum ground launch airspeed is for the pilot to signal  the launch operator to reduce tow speed. After the reduction  of the towing speed, the pilot can resume normal climb. If  the tow speed is not reduced, the glider may be incapable of  climbing to safe altitude. A broken towline is the most common type of problem when  doing a ground launch.  [Figure 8-16]  When there is a towline  failure, the glider pilot must pull the release handle and  immediately lower the nose of the glider to achieve and maintain  a safe airspeed. The distinguishing features of the ground launch  are nose-high pitch attitude and a relatively low altitude for a  significant portion of the launch and climb. If a towline break  occurs and the glider pilot fails to respond promptly, the nose- high attitude of the glider may result in a stall. Altitude may  be insufficient for recovery unless the pilot recognizes and  responds to the towline break by lowering the nose. The launch equipment operator manages ground launch  towline speed. Because the launch equipment operator is  remote from the glider, it is not uncommon for initial tow to  be too fast or too slow. If the towline speed is too great, the  glider is not able to climb very high because of excessive  airspeed. If the towline speed is too low, the glider may be  incapable of lift-off or could stall after becoming airborne.  Once airborne, the glider could be incapable of further  climb. The pilot should use appropriate signals to direct the  launch operator to increase or decrease speed. The pilot must  anticipate and be prepared to deal with these situations. In  the event these abnormal situations develop, the pilot’s only  alternative may be to release the towline and land ahead. Ground launch may be interrupted by a ground launch  mechanism malfunction. A gradual deceleration in rate  of climb and/or airspeed may be an indication of such a  malfunction. If a launch mechanism malfunction is suspected,  release and land ahead. 8-14