TM 1-1510-218-10 2-10 be    a    minimum    of    60    minutes    in    duration    unless restricted    by    Air    Traffic    Control,    turbulence,    other weather conditions, or emergencies. (d)  Takeoff.          All    missions    with    over 12,500  pounds  GTOW  shall  be  flown  on  a  smooth, paved runway.  Takeoffs shall not be performed with a tailwind. (2)   Maximum Weight Operation. (a)  Takeoff.  Maximum GTOW is 14,000 pounds. (b)  Landing.        Maximum    gross    landing weight is 12,500 pounds. (c)  Maximum  Ramp  Weight.    Maximum ramp weight is 14,090 pounds. (d)  Maximum Zero Fuel Weight.   Maximum zero fuel weight is 11,000 pounds. 2-6.  EXHAUST AND PROPELLER DANGER AREAS. Exhaust    and    propeller    danger    areas    to    be avoided by personnel while aircraft engines are being operated   on   the   ground   are   depicted   in   Figure  2-5.   Distance  to  be  maintained  with  engines  operating  at idle   are   also   shown.      Temperature   and   velocity   of exhaust  gases  at  varying  locations  aft  of  the  exhaust stacks  are  shown  for  maximum  power.    The  danger area extends to 40 feet aft of the exhaust stack outlets.   Distances  to  be  maintained  with  engines  operating  at idle and propeller danger areas are also shown. 2-7.  LANDING GEAR SYSTEM C D1. The  landing  gear  is  a  retractable,  tricycle  type, electrically operated by a single dc motor.  This motor drives the main landing gear actuators through a gear box  and  torque  tube  arrangement,  and  also  drives  a chain  mechanism  which  controls  the  position  of  the nose  gear.    Positive  down-locks  are  installed  to  hold the  drag  brace  in  the  extended  and  locked  position.   The   down-locks   are   actuated   by   over-travel   of   the linear jackscrews and are held in position by a spring- loaded   over-center   mechanism.      The   jackscrew   in each actuator holds all three gears in the UP position, when the gear is retracted.  A friction clutch between the gearbox and  the torque shafts protects the motor from  electrical  overload  in  the  event  of  a  mechanical malfunction.  A 150-ampere current limiter, located on the  dc  distribution  bus  under  the  center  floorboard, protects  against  electrical  overload.    Gear  doors  are opened   and   closed   through   a   mechanical   linkage connected   to   the   landing   gear.      The   nose   wheel steering mechanism is automatically centered and the rudder  pedals  relieved  of  the  steering  load  when  the landing   gear   is   retracted.      Air-oil  type  shock  struts, filled   with   compressed   air   and   hydraulic   fluid,   are incorporated with the landing gear.  Gear retraction or extension time is approximately 6 seconds. a.   Landing   Gear   Control   Switch.      Landing gear   system   operation   is   controlled   by   a   manually actuated  wheel-shaped switch, placarded  LDG GEAR CONTR   UP  /   DN,  on  the  left  subpanel,  Figure  2-6.   The  control  switch  and  associated  relay  circuits  are protected   by   a  5 -ampere  circuit  breaker,  placarded LANDING   GEAR   RELAY,   on   the   overhead   circuit breaker panel. b.  Landing    Gear    Down    Position-Indicator Lights.     Landing  gear  down  position  is  indicated  by three   green   lights   on   the   left   subpanel,   placarded GEAR   DOWN.      These   lights   may   be   checked   by operating   the   ANNUNCIATOR   TEST   switch.      The circuit   is   protected   by   a   5-ampere   circuit   breaker, placarded   LANDING   GEAR   IND,   on   the   overhead circuit breaker panel. c.   Landing   Gear   Position   Warning   Lights.   Two   red   bulbs,   wired   in   parallel   and   activated   by microswitches    independent    of    the    landing    GEAR DOWN  position  indicator  lights,  are  positioned inside the   clear   plastic   grip   on   the   landing   gear   control handle.   These lights illuminate whenever the landing gear handle is in either the  UP or DN position and the gear is in transit.  Both bulbs will also illuminate should either    or    both    power    levers     be    retarded    below approximately  81%  N₁  when  the  landing  gear  is  not down and locked.   To turn the handle lights off during single-engine    operation,    the    power    lever    for    the inoperative   engine   must   be   advanced   to   a   position which  is  higher  than  the  setting  of  the  warning  horn microswitch.   Extending the landing gear will also turn the   lights   off.      Both   red   lights   indicate   the   same warning conditions, but two are provided for a fail-safe indication in the event one bulb burns out.   The circuit is protected by  a  5-ampere circuit breaker, placarded LANDING GEAR IND, on the overhead circuit breaker panel. d.  Landing  Gear  Warning  Light  Test  Button.   A test button, placarded   HDL  LT  TEST, is located on the  left  subpanel.    Failure  of  landing  gear  handle  to illuminate   red  when  this  button  is  pressed  indicates two  defective  bulbs  or  a  circuit  fault.    The  circuit  is protected   by   a  5 -ampere  circuit  breaker,  placarded LANDING GEAR RELAY CONTROL, on the overhead circuit breaker panel.