TM 55-1510-222-10 continues to increase, turn battery switch OFF. 2. Battery switch OFF. NOTE The  battery  may  be  turned  back  ON only for gear and flap extension and approach to landing.  Battery may be usable   after   a   15   20   minute   cool down period. 3. Battery  switch  (landing  gear/flap  extension only) ON. h. Avionics  Master  Power  Switch  Failure.    If the Avionics Master Power Switch fails to operate in the ON position, perform the following: 4. AVIONICS MASTER CONTR circuit breaker-Pull. NOTE The avionics power relay is normally hot.  Pulling  the  AVIONICS  MASTER CONTR   circuit   breaker   will   remove power   to   the   relay,   thus   allowing electrical   power   to   the   associated busses. 9-28.  EMERGENCY DESCENT. The following procedure assumes the structural integrity of the aircraft and smooth flight conditions. If structural integrity  is  in  doubt,  limit  speed  as  much  as  possible, reduce   rate   of   descent   if   necessary,   and   avoid   high maneuvering  loads.    For  emergency  descent,  perform the following: 1. Power levers IDLE. 2. Propeller levers HIGH RPM. 3. Flaps APPROACH. 4. Gear DN. 5. Airspeed 178 KIAS maximum. NOTE Windshield defogging may be required. 9-29.  FLIGHT CONTROLS MALFUNCTION. Use  the  following  procedures,  as  applicable,  for  flight control malfunctions. a. Autopilot/Yaw Damp Emergency Disconnection.  The autopilot can be disengaged by any of the following methods: 1. Pressing the DISC TRIM AP YD disconnect switch (control wheels). 2. Pressing  the  AP  ENGAGE   pushbutton   on the autopilot mode selector control panel. 3. Pressing  the  go-around  switch  (left  power lever), (yaw damper will remain on). 4. Pulling the AP CONTR and AFCS DIRECT circuit breakers (overhead control panel). 5. Setting AVIONICS MASTER POWER switch (overhead control panel) to the off position. 6. Setting  aircraft  MASTER  switch  (overhead control panel) to the OFF position. b. Unscheduled Rudder Boost Activation. Rudder   boost   operation   without   a   large   variation   of power    between    engines    indicates    a    failure    of    the system.  Perform the following: 1. Control wheel disconnect switch Disconnect and hold (hold to first level). 2. Rudder boost control switch OFF. 3. Rudder  boost  circuit  breaker  Pull  (Provided that rudder boost does not deactivate). 4. Control wheel disconnect Release. 5. Yaw damper Reengage. c. Unscheduled Electric Trim.    In  the  event  of unscheduled electric elevator trim, perform the following: 1. Electric trim switch OFF. 2. Elevator trim circuit breaker Pull. 9-30.  LANDING EMERGENCIES. WARNING Structural   damage   may   exist   after landing  with  brake,  tire,  or  landing gear malfunctions. Under no circumstances  shall  an  attempt  be made   to   inspect   the   aircraft   until jacks have been installed. a. Landing Gear Unsafe Indication. 1. Landing gear control switch Check DN. 2. Landing   gear   control   and   gear   indicator circuit breakers Check in. 9-11