TM  1-1520-240-10            2-2-3 WARNING If the FIRE PULL handle warning lights are covered by the NVG filters during daylight operation, illumination of the fire warning lights may not be apparent in the event of an engine fire. Do not operate the aircraft with the NVG filters covering or obscuring the fire warning lights unless night vision goggles are being used. The NVG filter is attached to one end of the FIRE PULL handle by hinged fitting. The other end of the filter holder forms a tab by which the filter holder and filter may be rotated about the hinged fitting. For NVG operations, the filter holder is rotated to a closed position over the front of the FIRE PULL handle cover. In this position, the fire warning light is NVG compatible. For normal operations, the filter holder is rotated from the closed position to the fully open position. In this position, the FIRE PULL han- dle warning lights will be red. CAUTION If there is a fire in both engine compart- ments, do not pull both FIRE PULL han- dles   simultaneously.   Extinguish   fire   in one  compartment  only  as  described  be- low. Leave the FIRE PULL handle out after fire has been extinguished. Proceed in a like manner to extinguish fire in the other engine compartment. When an engine compartment fire occurs on either side, the respective pair of warning lights comes on. The ap- propriate FIRE PULL handle is pulled, that engine fuel shutoff valve closes and the AGENT DISCH switch is armed. Selection and discharge of either fire bottle is accom- plished by placing the AGENT DISCH switch to BTL 1 or BTL 2. After depletion of the charge in the initially se- lected bottle, the remaining bottle can be discharged to the same engine compartment by selecting the opposite position on the AGENT DISCH switch. The other FIRE PULL handle performs the same function for its respec- tive engine compartment. 2-2-4.  AGENT DISCH Switch A  three-position  AGENT  DISCH  (discharge)  switch  is above the FIRE PULL handles on the center instrument panel (fig. 2-2-1). The lever-lock momentary switch posi- tions  are  BTL  1,  neutral,  and  BTL  2.  When  BTL  1  is selected, the agent is discharged from the No. 1 bottle into the selected engine compartment. When BTL 2 is selected, the agent is discharged from the No. 2 bottle into the selected engine compartment. Only two fire ex- tinguisher agent bottles are provided. If the agent from both bottles is used in combating a fire in one engine compartment, agent will not be available should a fire occur in the other engine compartment. Power is sup- plied from the corresponding No. 1 or No. 2 DC essential bus through the ENGINE NO. 1 and NO. 2 FIRE EXT circuit breakers on the No. 1 and No. 2 PDP. 2-2-5.  FIRE DETR Switch. A two-position FIRE DETR (detector) switch is below the AGENT DISCH switch on the top center section of the center instrument panel (fig. 2-2-1). It is labeled FIRE DETR and TEST. The toggle switch is spring-loaded to FIRE  DETR  which  monitors  the  engine  fire  detection system. When the switch is placed to TEST, it checks the operation of the engine fire detection system by closing relays in both controls units and the warning lights in both FIRE PULL handles illuminate. Power to operate the test circuit is supplied by the DC essential bus through the LIGHTING CAUTION PNL circuit breaker on the No. 1 PDP. 2-2-6.  Hand Fire Extinguishers. WARNING Avoid prolonged exposure (5 minutes or more) to high concentrations of fire extin- guishing   agent   and   its   decomposition products because of irritation to the eyes and nose. Adequate respiratory and eye relief from excessive exposure should be sought as soon as the primary fire emer- gency permits. Use of oxygen for person- nel is recommended. Three portable 6.3 pound capacity hand fire extinguish- ers are provided in the helicopter. One is in the cockpit, on the floor to the right of the pilot’s seat. Two hand fire extinguishers are in the cabin section. One on the for- ward bulkhead and one in the left rear, just forward of the ramp. 2-2-7.  Emergency Troop Alarm and Jump Lights. Two emergency troop alarm and jump light boxes are in the cargo compartment. The forward box is on the bulk- head and above the avionics equipment shelves and the aft box is on the left side of the fuselage above the ramp at sta. 575. Each box has an electric bell in the center with a red light fixture on one side and a green light fixture on the other side. The TROOP WARN panel on the over- head switch console is used to operate the emergency troop alarm and jump lights. The emergency troop alarm and jump lights have several functions. They can be used to notify passengers and crew with predetermined signals in time of emergency. The  jump  lights  can  be  used  to  notify  flight  engineer during airborne delivery operations and to alert the troop commander  during  paratroop  drop  missions.  Refer  to Chapter 9 for standard use of the troop alarm.