TM  1-1520-240-10            2-9-1 SECTION  IX.  UTILITY SYSTEMS 2-9-1.  Anti Icing Systems. Anti icing is provided for the pitot tubes, AFCS yaw ports, and pilot and copilot windshields. The center windshield is not anti-iced, it is only defog. 2-9-2.  ANTI ICE Panel. The ANTI ICE panel is located on the overhead switch panel (fig. 2-9-1). It has three two-position W/S (wind- shield)  switches  labeled  CPLT,  CTR,  and  PLT.  The switches positions are OFF and ON. In addition, a two- position PITOT heat switch is in this panel. The switch positions OFF and ON. Power for the pilot and center windshields is from the No. 2 AC bus through the WSHLD ANTI ICE HEAT PILOT and CTR circuit breakers. Power for the copilot wind- shield  is  from  the  No.  1  AC  bus  through  the  WSHLD COPLT HEAT circuit breaker on the No. 1 PDP. Anti-ice control  for  the  pilot  and  center  windshield  is  from  the 28-volt  No.  2  DC  bus  through  the  WSHLD  ANTI  ICE CONT CTR and PILOT circuit breakers on the No. 2 PDP. Anti-ice  control  for  the  copilot  windshield  is  from  the 28-volt No. 1 DC bus through the WSHLD COPLT CONT circuit breaker on the No. 1 PDP. Power to operate the heater elements in the pitot tubes and yaw ports is sup- plied by the No. 2 AC bus through the PITOT HEAT and YAW PORT HEAT circuit breakers on the No. 2 PDP. a. W/S Switches.  The pilot and copilot windshields are anti-iced and defogged electrically. The center wind- shield is defogged but not anti-iced. The laminated wind- shield  panels  are  heated  electrically  by  current  which passes  through  a  transparent  conductive  coating  em- bedded between the layers. Figure  2-9-1.  Anti Ice Panel CAUTION If windshield bubbling or delamination oc- curs around the sensor element, immedi- ately  place  switch  to  OFF  for  that  wind- shield. When any switch is moved to ON, current flows to the associated temperature controller and then to the wind- shield. As the temperature of the windshield rises to a preset value (about 44_), as sensed by the sensor ele- ment,  the  electrical  current  to  the  windshield  is  inter- rupted by the temperature control relay. Once the wind- shield   has   cooled   sufficiently,   electrical   current   is reapplied. This causes a cycling effect which maintains windshield temperature within operating limits. Operating temperature is on in less than 1 minute after the switch is placed to on. When the switch is placed to OFF, the anti-icing system is deenergized. b. PITOT Heat Switch.  Heating elements prevent ice accumulation in the pitot tubes and the yaw ports. When the PITOT switch is placed to ON, power to the heater elements in the pitot tubes and yaw ports is ap- plied.  When  the  switch  is  placed  to  OFF,  the  heating elements are deenergized. 2-9-3.  MAINTENANCE PANEL. The MAINTENANCE PANEL is on the right side of the cabin above the ramp (fig. 2-9-2). The panel is provided to  assist  in  the  identification  of  system  malfunction  or condition  that  may  require  servicing  or  other  mainte- nance. The panel is divided into four sections. They are labeled TRANSMISSION, HYDRAULICS, ENGINE, and GROUND CONTACT. 2-9-4.  TRANSMISSION Section. This   section   monitors   the   FWD,   COMB,   AFT,   AFT SHAFT, LEFT, and RIGHT transmissions. It consists of six CHIP DETECTOR magnetic indicators, six DEBRIS SCREEN a magnetic indicators, six MAIN OIL PRESS indicating   PRESS-TO-TEST   lights,   three   AUX   OIL PRESS  indicating  PRESS-TO-TEST  lights,  and  five OVERTEMP magnetic indicators. Power to operate the indicators is supplied by the No. 1 DC bus through the HYDRAULIC MAINT PNL circuit breaker on the No. 1 PDP. a. CHIP  DETECTOR  Magnetic  Indicators.  When the corresponding CHIP DETECTOR is bridged by fer- rous  particles,  the  associated  chip  detector  indicator changes from all-black to black-and-white. In addition, the XMSN CHIP DET or ENG CHIP DET caution capsule illuminates on the master caution panel.