TM  55-1510-221-10 8-60.  INSTRUMENT  APPROACHES. There  are  no  unusual  preparations  or  control techniques required for instrument approaches. The approaches are normally flown at an airspeed of V ref +20 until transitioning to visual flight. 8-61. AUTOPILOT APPROACHES. There  are  no  special  preparations  required  for placing the aircraft under autopilot control. Refer to Chapter  3  for  procedures  to  be  followed  for  auto- matic   approaches. NOTE The ILS localizer and glideslope warning flags indicate insufficient signal strength to  the  receiver.  Certain  electrical  mechan- ical  malfunctions  between  the  receiver and  indicators  may  result  in  erroneous localizer/glideslope information without a warning flag. It is recommended that ILS information  be  crosschecked  with  other flight  instruments  prior  to  and  during final approach. Utilization of NAV TEST on  VOR  control  prior  to  the  final approach fix may detect certain malfunc- tions not indicated by the warning flags. Section III. FLIGHT CHARACTERISTICS 8-62.   STALLS. A prestall warning in the form of very light buf- feting  can  be  felt  when  a  stall  is  approached.  An aural  warning  is  provided  by  a  warning  horn.  The warning horn starts sounding approximately five to ten knots above stall speed with the aircraft in any configuration.  If  correct  stall  recovery  technique  is used, very little altitude will be lost during the stall recovery. For the purpose of this section, the term "power-on"  shall  mean  that  both  engines  and  pro- pellers  of  the  aircraft  are  operating  normally  and power  is  set  at  approximately  50%.  The  term "power-off"  shall  mean  that  both  engines  are  operat- ing  at  idle  power.  Landing  gear  position  has  no effect on stall speed. During practice, enter power- off stalls from normal glides. Enter power-on stalls by  smoothly  increasing  pitch  attitude  to  decrease airspeed  by  approximately  one  knot  per  second  until stall  occurs. a. Power-On  Stalls.  The  power-on  stall  atti- tude  is  very  steep  and  unless  this  high-pitch  attitude is maintained, the aircraft will generally “settle“ or “mush“ instead of stall. It is difficult to stall the air- craft inadvertently in any normal maneuver. A light buffet precedes most stalls, and the first indication of approaching stall is generally a decrease in control effectiveness,   accompanied   by   a   “chirping“   tone from the stall warning horn. The stall itself is char- acterized  by  a  rolling  tendency  to  the  right,  if  the aircraft is allowed to yaw. The proper use of rudder will prevent the tendency to roll. A slight pitching tendency  will  develop  if  the  aircraft  is  held  in  the stall,  resulting  in  the  nose  dropping  sharply,  then pitching  up  toward  the  horizon;  this  cycle  is repeated until recovery is made. Control is regained very quickly with little altitude loss, providing the nose is not lowered excessively. Begin recovery with forward movement of the control wheel and a grad- ual return to level flight. The roll tendency caused by yaw is more pronounced in power-on stalls, as is the pitching tendency; however, both are easily con- trolled after the initial entry. Power-on stall charac- teristics are not greatly affected by wing flap posi- tion,   except   that   stalling   speed   is   reduced   in proportion to the degree of wing flap extension. b. Power-Off Stalls. Power-off stalls are char- acterized by a right rolling tendency, as the stall is approached. Elevator control is effective to the stop and  the  pitch  attitude  can  be  maintained  with  a deceleration  rate  of  1  knot/sec.  Light  to  moderate buffet commences approximately 5 - 8 knots above the stall and the warning horn will sound and con- tinue to the stall. With wing flaps down, the right rolling  tendency  is  more  pronounced  and  stalling speed is much slower than with the wing flaps up. The Stall Speed Chart (fig. 8-2) shows the indicated power-off  stall  speeds  with  the  aircraft  in  various configurations. Altitude loss during a full stall will be approximately 800 feet. c. Accelerated  Stalls.  The  aircraft  gives  notice- able stall warning in the form of buffeting when the stall  occurs.  The  stall  warning  and  buffet  can  be demonstrated  in  turns  by  applying  excessive  back pressure on the control wheel. 8-63.   SPINS. Intentional  spins  are  prohibited.  If  a  spin  is inadvertently  entered  use  the  following  recovery procedure: 8-24