Beechcraft C-12C Operator And Technical Reference Manual

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Beechcraft C-12C Operator And Technical Reference Manual Manual pdf 155 page image

TM 1-1510-218-10CHAPTER 3AVIONICS (COMMON) C D T1 T2Section I. GENERAL3-1. GENERAL DESCRIPTION.This chapter covers the avionics equipmentinstalled common to the C–12C, C-12D1, C-12D2,C-12T1, and C-12T2 aircraft. It includes a briefdescription of the avionics equipment, its technicalcharacteristics, capabilities, and locations. Avionicsinstalled in the C-12C and D1 aircraft are covered inChapter 3A. Avionics installed in the C-12D2 aircraftare covered in Chapter 3B. Avionics installed in C-12T1 and T2 aircraft are covered in Chapter 3C.3-2. AVIONICS EQUIPMENT CONFIGURATION.The avionics configuration of the aircraft iscomprised of three groups of electronic equipment.The communication equipment group consists of theinterphone, UHF command C D , V/UHF commandT , and HF command systems. The navigationequipment group provides the pilot and copilot with theinstrumentation required to establish and maintain anaccurate flight course and position and to make anapproach on instruments under InstrumentMeteorological Conditions (IMC). The navigationgroup includes equipment for determining altitude,attitude, position, destination, range and bearing,heading reference, groundspeed, and drift angle. Thetransponder and radar group includes an identificationcapability, a position and emergency tracking system,and a radar system to locate potentially dangerousweather areas. A Ground Proximity Altitude AdvisorySystem (GPAAS) is also installed.3-3. POWER SOURCE.a. DC Power. DC power for the avionicsequipment is provided by four sources: the aircraftbattery, left and right generators, and external power.Power is routed through a 50-ampere circuit breaker tothe avionics power relay that is controlled by theAVIONICS MASTER POWER switch on the overheadcontrol panel, Figure 2-15. Individual system circuitbreakers and the associated avionics buses are shownin Figures 2-27 and 2-28 and Tables 2-6, 2-7, 2-8, and2-9. With the switch in the ON position, the avionicspower relay is de–energized and power is appliedthrough both the AVIONICS MASTER POWER #1 and#2 circuit breakers to the individual avionics circuitbreakers on the overhead circuit breaker panel, Figure2-16. In the off (aft) position, the relay is energizedand power is removed from avionics equipment.When external power is applied to the aircraft, theavionics power relay is normally energized, removingpower from the avionics equipment. To apply externalpower to the avionics equipment, move the AVIONICSMASTER POWER switch to the EXT PWR position.This de–energizes the avionics power relay and allowspower to be applied to avionics equipment.b. AC Power. Two inverters provide ac powerfor the avionics equipment. The inverters supply 115-volt and 26-volt single-phase ac power when operatedby the INVERTER #1 or #2 switches. Either inverter iscapable of powering all avionics equipment requiringac power. 115 Vac power from the inverters is routedthrough fuses and transformers in the nose avionicscompartment. The transformers provide the required26 Vac needed by avionics equipment.Section II. COMMUNICATIONS3-4. COMMUNICATIONS DESCRIPTION.The common avionics in the communicationsequipment group consists of the microphone switches,microphone jacks, and headset jacks.3-5. MICROPHONE SWITCHES, MICROPHONEJACKS, AND HEADSET JACKS.a. Microphone Switches. A bi-levelmicrophone switch, placarded INTPH XMIT / MIC, islocated on the pilot's and copilot's control wheels,Figure 2-22, and copilot's floor.(1) MIC INTPH / XMIT Switch. Keysselected facility.(a) INTPH. When pressed to first detent,keys interphone facility regardless of position oftransmitter selector switch.(b) XMIT. When pressed fully, keysfacility indicated on transmitter selector switch.3-1