TM  1-1520-240-10            2-3-5 Figure  2-3-4.  ENGINE START PANEL  712 2-3-15.  START Panel.  712 The START panel is located on the overhead switch pan- el (fig. 2-3-4). It consists of the ENG 1 and ENG 2 START- ER ON indicator lights and two start switches. a. Start Switches.  The switches are labeled OFF, MTR, and START. They are locked in OFF, detented in MTR and spring-loaded from START to MTR. At MTR, the engine is rotated by the starter, but ignition and start fuel circuits are deenergized. At START, the engine is rotated with start fuel and the ignition circuits are energi- zed. MTR is selected during starting, in case of engine fire or to clear the combustion chamber. b. STARTER ON Indicator Lights.  The STARTER ON indicator lights will illuminate when the associated START  switch  is  moved  to  MTR  or  START.  The  light alerts the pilots when the START switch is inadvertently left at MTR. Power is supplied by the No. 1 and No. 2 DC essential buses through the ENGINE NO. 1 and NO. 2 START & TEMP circuit breakers on the No. 1 and No. 2 PDP. 2-3-16.  Ignition Lock Switch. An ignition system lock switch (11, fig. 2-1-3) is installed on the right side of the console forward of the thrust lever. The key-operated switch prevents unauthorized use of the helicopter. When the switch is off, the circuits of the ignition exciters and the start fuel solenoids of both en- gines are open. Therefore, the engines cannot be star- ted. Be sure both START switches are OFF before turn- ing the ignition lock switch ON or OFF. 2-3-17.  Engine Instruments and Cautions. The engine instruments are the gas producer tachome- ter, the dual torquemeter, power turbine inlet tempera- ture (PTIT), fuel flow, oil pressure and oil temperature indicators. The caution capsules are the NO. 1 and NO. 2 ENGINE OIL LOW and the NO. 1 and NO. 2 ENG CHIP DET. 2-3-18.  Gas Producer Tachometer.   Two gas producer tachometers (N1), one for each en- gine, are on the center instrument panel (6, fig. 2-1-8 and 6, 2-1-12), above the PTIT indicators. Each tachometer displays gas producer turbine speed in percent of N1. Each tachometer operates from power supplied by a gas producer tachometer generator on the accessory gear box section of each engine.  712   The outer scale of the tachometer is calibrated from 0 to 100 in increments of two. The smaller, vernier scale is calibrated from 0 to 10, in increments of one.  714A   The tachometer is calibrated from 0 to 110. 2-3-19.  Torquemeter. One torquemeter is on the copilot instrument panel and the other on the pilot instrument panel (1, fig. 2-1-7 and 17, fig. 2-1-9). Each torquemeter has two pointers, one for each engine, labeled 1 and 2. Each torquemeter has a range of 0 to 150 percent. The system consists of a power output shaft, torquemeter head assembly, power supply  unit,    714A    ratio  detector  power  supply  unit (RDPS), and a torquemeter junction box. Power to oper- ate the torquemeter is provided by No. 1 and No. 2 AC buses through the ENGINE NO. 1 and NO. 2 TORQUE circuit breakers on the No. 1 and No. 2 PDP. Power for the power supply unit   714A   and RDPS is provided by the No. 1 and No. 2 DC buses through the DC ENGINE NO. 1 and NO. 2 TORQUE circuit breakers on the No. 1 and No. 2 PDP. 2-3-20.  Power   Turbine   Inlet   Temperature   Indica- tors. Two power turbine inlet temperature (PTIT) indicators, one for each engine, are on the center instrument panel (7, fig. 2-1-8, 7, fig. 2-1-12). Each indicator is calibrated from 0_ to 1,200_C. The temperatures registered on the PTIT indicator are transmitted by chromel-alumel ther- mocouples. the thermocouples sense gas temperature at the power turbine inlet and transmit an average gas temperature reading to the PTIT indicator in the cockpit. 712   When power turbine inlet temperature increases to the emergency power range, the EMERG PWR indicator light  will  illuminate  and  DC  power  is  supplied  to  the EMERGENCY POWER panel.  714A   When power turb- ine inlet temperature increases to the contingency power range, the ENG CONT PWR master caution advisory panel capsule will illuminate. 2-3-21.  Engine Oil Pressure Indicator. An engine oil pressure indicator on the center instrument panel  is  provided  for  each  engine  (17,  fig.  2-1-8  and 2-1-12). Each indicator relates pressure sensed at No. 2 bearing by an oil pressure transmitter mounted near the engine.  Each  engine  oil  pressure  indicator  displays  a pressure range from 0 to 200 psi. Power to operate the engine oil pressure circuit is supplied by the AC instru- ment buses through the ENGINE NO. 1 and NO. 2 OIL PRESS circuit breakers on the No. 1 and No. 2 PDP. 2-3-22.  Engine Oil Temperature Indicator.   Two engine oil temperature indicators are on the center the instrument panel (18, fig. 2-1-8 and 2-1-12). Each engine oil temperature indicator is calibrated from -70_ to + 150_C. A temperature probe within the lubrication lines of the engine, before the fuel-oil cooler, is the point at which the temperature is sensed. Power to operate the resistance-type oil temperature circuit is supplied by the No. 1 and No. 2 DC buses through the ENGINE NO. 1