1. ELECTRICAL SYSTEM The helicopter is equipped with a 28 VDC electrical system. Power for this system is obtained from a nickelcadmium 24 volt, 17 ampere-hour battery and a 30 volt, 200 ampere starter-generator. Major components of the DC power system include the battery, starter-generator, voltage regulator, relays, 28 VDC bus, and circuit breakers. All circuits in the electrical system are single wire with fuselage common ground return.

2. The negative terminals of the starter-generator and the battery are grounded to the helicopter structure. Controls for the electrical system are located on the overhead console and instrument panel. The generator is provided with over voltage protection set at 31 + 1 volts. Upon exceeding this limit, the voltage regulator will disconnect the starter-generator from the system. The failure of the generator can be determined by the GEN FAIL caution light and a zero loadmeter reading. The battery can supply emergency DC load for approximately 1 hour with a 17 ampere drain.

3. The BATTERY switch may be placed in the ON position after external power is applied. In the ON position, battery charging is supplied by external power and must be monitored. In the event the BATTERY HOT warning light illuminates, the BATTERY switch shall be turned OFF. If the Battery switch is turned OFF, and the BATTERY RLY caution light illuminates, this indicates that the battery relay has failed to open. If the battery relay fails to open, the battery will continue to receive a charge from the generator. To prevent this, the pilot should turn GEN switch OFF.

4. The battery will continue to run all electrical systems through the closed battery relay. To reduce the load on the overheated battery, the pilot should pull the circuit breakers on all nonessential systems. The LEFT BOOST circuit breaker should be left in to ensure that fuel transfer from front tanks to main tank continues. External power may be supplied to the helicopter by means of a receptacle located on the lower front section of the helicopter. An auxiliary power unit capable of delivering 28 VDC with a 500 ampere rating is required.

5. AUDIO WARNING SYSTEM The ROTOR LOW RPM and ENG OUT audio warnings are emitted from cabin horns located aft and to the left of the overhead console. The muting button for the system is located on upper right side of instrument panel, and mutes warning system audio. The rotor RPM audio warning activates (simultaneously with ROTOR LOW RPM caution light illumination) whenever the ROTOR decays below 90% RPM. The rotor RPM audio will produce a steady sound until the Rotor increases above 90% RPM.

6. Helicopters equipped with a WRN HORN MUTE system will produce a steady sound when the ROTOR decays below 90% RPM, regardless of collective position. The engine out audio warning (if functional) is activated (simultaneously with ENG OUT warning light illumination) when the GAS PRODUCER drops below 55 + 3% RPM. The engine out audio will produce an intermittent sound until the GAS PRODUCER increases above 55% RPM.

8. BATTERY BATTERYSWITCH BATTERYRELAY STARTERGENERATOR LOADMETER GENERATOR RESET SWITCH VOLTAGEREGULATOR LINE CONTROL RELAY STARTERSWITCH STARTERRELAY EXTERNALPOWERRECEPTACLE EXT. POWER RELAY 28 VDC BUS

9. LEFT FUEL BOOST CIRCUIT LEFT FUEL BOOST PUMP BATTERYSWITCH FUELSWITCH FUELSHUTOFFVALVE BATTERYRELAY BATTERY 28 V BUS BUS

12. CARGO HOOK TYPE OF OPERATION Operation of the helicopter with no load on external cargo suspension hook is authorized under the standard airworthiness certificate under VFR conditions without removing the unit from the helicopter. With a load attached to suspension assembly, operation shall be conducted in accordance with appropriate operating rules for external loads under VFR conditions.

13. WEIGHT/CG Actual weight change shall be determined after cargo hook is installed and ballast readjusted, if necessary, to retain empty weight CG within allowable limits. Maximum approved gross weight for takeoff and landing, External Load - 4250 Lbs. CAUTION LOADS THAT RESULT IN GROSS WEIGHTS ABOVE 4150 LBS SHALL BE CARRIED ON CARGO HOOK AND SHALL NOT BE IMPOSED ON LANDING GEAR.

14. AIRSPEED VNE is 87 KIAS and light weight, high drag loads require a swivel connector between the cargo hook and the sling to prevent unstable oscillations in flight above 20 KIAS. CAUTION AIRSPEED WITH EXTERNAL CARGO IS LIMITED BY CONTROLLABILITY. CAUTION SHOULD BE EXERCISED WHEN CARRYING EXTERNAL CARGO, AS THE HANDLING CHARACTERISTICS MAY BE AFFECTED BY THE SIZE, WEIGHT, AND SHAPE OF THE CARGO LOAD, AND IS NOT TO EXCEED 87 KIAS.

15. PLACARDS CARGO LOAD LIMIT 2000 POUNDS. NOTE This is an optional item to the basic aircraft and complete information on its procedures and limitations may be found in the Supplements Section of the Flight Manual.

16. CARGO HOOK ASSEMBLY ELECTRICALRELEASE MANUALRELEASE CARGOHOOK SUPPORTASSEMBLY ROLLERASSEMBLY

17. EMERGENCY FLOTATION LANDING GEAR TYPE OF OPERATION Operation with the pop-out floats inflated is limited to flight to a servicing facility for repacking and recharging the system. Amphibious operations are not approved. The floats and covers shall be installed and ground handling wheels removed for all flight operations. Accomplish preflight float system check daily prior to performing over water operations.

18. AIRSPEED FLOATS STOWED - Floats stowed, covers installed - Same as basic helicopter. Doors on or off in any combination - Same as basic helicopter. CAUTION DURING FLIGHT AT ALTITUDES ABOVE 500 FEET AND AT AIRSPEEDS OF 52 KIAS (60 MPH) AND ABOVE, THE SYSTEM SHOULD BE DEACTIVATED BY POSITIONING THE FLOAT MANUAL ARM SWITCH TO THE OFF POSITION, GUARD CLOSED.

19. FLOATS INFLATED - Maximum inflation airspeed - 52 KIAS (60 MPH). Maximum allowable airspeed, floats inflated - 61 KIAS (70 MPH). Maximum autorotation airspeed, floats inflated - 52 KIAS (60 MPH). CAUTION DURING THE INFLATION CYCLE UN- DESIRABLE PITCHING WILL OCCUR AT AIRSPEEDS ABOVE 52 KIAS (60 MPH).

20. RATE OF CLIMB Maximum rate of climb with floats inflated is 1000 feet per minute. PLACARDS FLOAT ARMING / INFLATION ABOVE 60 MPH IS PROHIBITED NOTE This is an optional item to the basic aircraft and complete information on its procedures and limitations may be found in the Supplements Section of the Flight Manual.

21. FLOTATION LANDING GEAR

23. BLEED AIR HEATER OPERATION With the Bleed Air Heater kit installed, there is no loss in helicopter performance when heater is turned OFF. With heater ON, performance will be reduced as shown in the supplement charts. NOTE TURBINE OUTLET TEMP (TOT) increases with bleed air heater operating.

24. SNOW DEFLECTORS TYPE OF OPERATION The Snow Deflector Kit shall be installed in conjunction with Particle Separator Kit when conducting flight operations in falling and/or blowing snow and the following limits apply: Operation at ground idle is limited to 5 minutes. Hover flight in falling and/or blowing snow is limited to 20 minute duration after which the helicopter must be landed and checked for snow and/or ice accumulation. Flight operations are prohibited when visibility in falling or blowing snow is less than one-half statute mile.

25. PERFORMANCE HOVER CEILING - PARTICLE SEPARATOR AND SNOW DEFLECTOR INSTALLED. To determine hover performance with the Particle Separator Kit installed use the appropriate hover chart (Purge on/Purge Off) To determine hover performance with the Snow Deflector Kit installed use the appropriate hover chart and the performance variation chart in the supplement.

27. BEFORE FLIGHT WHEN OPERATING IN SNOW CONDITIONS Thoroughly check cabin roof, transmission cowling, deflector baffles and, engine air intake areas. All areas checked must be clean and free of accumulated snow, slush, and ice before each flight Check engine air plenum chamber through the plexiglass windows on each side of the inlet cowling for snow, slush, or ice, paying particular attention to the firewalls and rear face of the Particle Separator. Clean thoroughly before each flight.

28. SNOW DEFLECTORS. Due to reduced performance at higher temperatures, it is recommended that snow deflectors be removed above 20 o C (68 o F). Snow deflectors must be removed when operating in temperatures above 30˚C.

29. POWER ASSURANCE CHECK The Snow Deflector supplement contains two Power Assurance Check charts. The first chart is to be used for helicopters equipped with snow deflectors. The second chart is to be used for helicopters equipped with snow deflectors and particle separator. Both charts are used in the same manner as the Power Assurance Check chart in the basic flight manual. Instructions for their use can be found at the beginning of the PERFORM-ANCE section of the basic flight manual. PARTICLE SEP PRG switch shall be ON when performing a power assurance check.

30. HIGH SKID LANDING GEAR DESCENT AND LANDING Tail-low run-on landings should be avoided to prevent nose down pitching. WARNING RUN-ON LANDINGS ON OTHER THAN A HARD, FIRM SURFACE SHOULD BE EXERCISED WITH CAUTION.

31. LITTERS LITTER OPERATION Copilot cyclic and collective controls must be removed and stowed when litters are installed. Patients must be restrained by litter straps.

32. ELECTRICALQUESTIONS?ELECTRICALQUESTIONS?