TM 1-1520-240-102-3-4 Figure 2-3-2. Emergency Engine Trim Panel 7122-3-11. Emergency Power System. 712CAUTIONTo prevent damage, monitor the torqueand the PTIT indicators when operatingwith emergency power. Failure to observethese indicators could result in seriousdamage to the drive train and engine.An emergency power system is included with T55-L-712engines. With the emergency power system, increasedpower is available on pilot demand and is actuated byraising the thrust control into the emergency powerrange. Refer to Chapter 5 for limitations on its use.When fuel flow increases to the point where PTIT is890_to 910_C, the EMERG PWR lights will illuminate on thecopilot and pilot instrument console (17, fig. 2-1-7 and 18,fig. 2-1-9). If temperature is maintained in this range formore than 5 seconds, the associated indicator will apply28-volt DC from the ENGINE NO. 1 and / or NO. 2 START& TEMP circuit breaker to the EMERGENCY POWERpanel. With 28-volt DC applied to the panel, the applica-ble emergency power timer will start, and the indicatorwill display a black-and-white flag. When thrust is re-duced below the emergency power level, the emergencypower light will extinguish and the timer will stop. Howev-er, the emergency power indicator will continue to displaythe black-and white flag. The flag can be reset on theground only.WARNINGBefore flight, be sure the two toppingstops are in their stowed position on theright side of the console. If stops are notstowed, be sure the stops are not installedon the fuel controls before you start theengine. Failure to check may result in in-ability to achieve emergency power in anemergency.Topping stops are stowed on each helicopter. The stopsare installed on the N1 control of each engine for mainte-nance engine topping checks. The stops provide an es-tablished fuel flow when topping. When not in use, thestops are stowed on the right side of the center consoleaft of the pedals.2-3-12. EMERGENCY POWER Panel. 712The EMERGENCY POWER panel is located on the over-head switch panel (fig. 2-3-3). It consists of an emergen-cy power indicator and a digital timer for each engine.They are labeled NO. 1 and NO. 2 ENGINE. The timercounts the minutes that emergency power is in use.2-3-13. Oil Supply System.The oil supply system is an integral part of the engine.The oil tank is part of the air inlet housing and the fillerneck is on the top of the housing. An oil level indicator ison the left side of the engine inlet housing. Refer to table2-15-1 for the tank capacity. If the oil level decreases toabout 2 quarts usable, the corresponding ENG OIL LOWcaution capsule will illuminate.Figure 2-3-3. Emergency Power Panel 7122-3-14. Engine Start System. 712The engine start system includes the hydraulic starterson each engine, the engine start valves and the solenoid-operated pilot valves on the utility system pressure con-trol modules, the START switch, and the start fuel sole-noids and ignition exciters on the engines.When the start switch is moved to MTR, the respectiveengine STARTER ON indicator light illuminates and thestart valve opens (fig. 2-3-4). The start valve appliesutility system pressure from the APU to the engine start-er: rotating the engine starter and compressor. At 15percent N1, the ENG COND lever is moved to GND. Thestart switch is immediately moved to START, energizingthe ignition exciter. Start fuel is sprayed into the combus-tor and combustion begins. Before PTIT reaches 200_C,the START switch is manually released to MTR. At MTR,the start fuel valve is closed and the ignition exciter isdeenergized.The engine then accelerates to ground idle speed. At 50percent N1, the START switch is manually moved to thelocked OFF position. At OFF, the pilot valve closes, clos-ing the start valve and deenergizing the STARTER ONindicator light. A relay in each engine start circuit is ener-gized when either START switch is at MTR or START.The relay, when energized, disables the start circuit ofthe opposite engine, thus preventing simultaneous dualengine starts. Power is supplied by the No. 1 and No. 2DC essential buses through the ENGINE NO. 1 and NO.2 START & TEMP AND IGN CIRCUIT BREAKERS ONTHE No. 1 AND No. 2 PDP.
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business