required by ATC, the pilot in charge (PIC) must notify  the control tower. If a control tower does not exist or  is not in operation, the PIC must notify the FAA flight  service station (FSS) serving that controlled airspace  before conducting any towing operations. These general effects should point out the possible danger  in attempting takeoff prior to achieving the recommended  lift-off speed. Due to the reduced drag in ground effect,  the tow plane may seem capable of takeoff well below the  recommended speed; however, lifting out of ground effect  with a lower than normal lift off speed may result in very  marginal initial climb performance. The glider will normally liftoff first. The pilot of the  glider should correct for crosswind until the tow plane  becomes airborne. At this point, the tow pilot must remain extra alert. The tail  of the tow plane may be lifted if the glider climbs too high.  Should this happen, the application of full-up elevator on the  tow plane may not be sufficient to prevent an accident from  happening. The tow pilot must be ready to pull the release  handle, releasing the glider and regaining control. As a rule  of thumb, the use of a 200 foot tow line would require the  glider to climb to over 20 feet above the altitude of the tow  plane to present a danger of upset. The takeoff is done by advancing the throttle smoothly and  quickly in one motion.  [Figure 12-11]  If the tow plane is  allowed to accelerate and then slow down, the glider may  overrun the tow line. This may result in the tow line becoming  tangled in the landing gear of the glider. The glider may then  be unable to release. Accelerate to liftoff speed keeping in  mind that during the takeoff phase of flight, ground effect  produces some important relationships. The tow plane  leaving ground effect will: After liftoff, a constant airspeed climb should be established.  The pilot of the glider should establish a position directly  behind the tow plane. The pilot of the tow plane should  maintain a constant ground track on the initial climb. Upon  reaching a safe altitude, a turn may be established to maintain  the desired departure path. Bank angle should be limited to  a maximum of 15–20°. Climb at full throttle unless otherwise required by the POH.  The fuel/air mixture should be leaned only in accordance with  the POH for maximum power. Each specific model of glider  has a published maximum aerotow speed, and the tow pilot  must be familiar with this speed, which may be very close  to the minimum safe speed of the tow plane.  [Figure 12-12] The tow pilot should understand that these are maximum  airspeeds. Plan to fly at a speed slower than the maximum  while maintaining safe tow plane flying speed. When towing  a different model of glider for the first time, obtain a briefing  from the glider pilot to ensure compliance with maximum  Figure 12-11.  The takeoff is done by smoothly and quickly advancing  the throttle in one motion so that the glider does not overrun the  tow line.  •  Require an increase in the angle of attack (AOA) to  maintain the same lift coefficient; •  Experience an increase in induced drag and thrust  required; •  Experience a decrease in stability and a nose-up  change in moment; and •  Produce a reduction in static source pressure and  increase in indicated airspeed. •  Stop engine/release tow line—this signal is given by  moving a hand back and forth across the throat. •  Tow plane ready—prior to takeoff, carefully look at  the glider to ensure the glider dive brakes are closed  and no one is standing in front of the wings or so close  to the launch path to create a hazard. It is important  to note, however, that some high-performance gliders  may make their initial takeoff roll with spoilers  open. Know your gliders and if in doubt, do not be  ashamed to question the glider pilot. Better to be a bit  embarrassed than to end up in the trees at the end of  the runway. Additionally, the tow pilot should ensure  that the traffic pattern is clear of aircraft. Once assured  that the glider is ready and the briefed departure path  is clear, the ready for takeoff signal may be given with  a waggle of the tow plane rudder. •  Stop operation or emergency—this signal is given by  a waving motion of the arms above the head. Takeoff and Climb 12-7