ELECTRICAL LOAD DISTRIBUTION. DESCRIPTION The power distribution system for this airplane consists of the main distribution bus and the essential distribution bus in the MCU along with the associated buses in the circuit breaker panel and their associated circuit breakers and switches. Each bus and circuit are labeled on the circuit breaker panel. The clock bus is fused within the MCU and is the only bus not connected to the master switch arrangement. The clock is continuously powered through a -amp fuse connected to the primary bus in the MCU. On PFD equipped airplanes, the clock bus is not used. The airplane can obtain electrical power for the essential bus from BAT, BAT, ALT, or ALT. In an emergency, as long as one of the four power sources remain functional, the essential bus will continue to supply electrical power to all of the flight critical instruments. The essential power bus normally receives electrical power from the ALT and BAT electrical systems. The main power bus receives power from the BAT system (ALT and/or BAT ). The main power bus provides power to the essential and nonessential power buses through a network of bus fuses or bus circuit breakers. For normal operation, the Essential Buses in the circuit breaker panel are powered from the essential distribution bus in the MCU through -amp circuit breakers. BAT is connected directly to the Essential Bus in the circuit breaker panel and will power the bus should the voltage coming from the MCU distribution buses drop below the battery voltage. Additionally, in the event of an ALT failure, the circuit breaker panel Essential Bus will be powered from ALT through the main distribution and essential distribution buses in the MCU. Main Bus, Main Bus, and the equipment Non-Essential Bus in the circuit breaker panel are powered from ALT through the main distribution bus in the MCU. The Avionics Non-Essential Bus in the circuit breaker panel is powered from circuit breaker panel Main Bus. Note: Individual circuit load charts and bus schematics showing system current flow during normal and failure modes are provided in the Wiring Manual. A. Circuit Protection Devices The electrical system in this airplane is protected by using circuit breakers and fuses. A circuit breaker panel is located near the pilot's right leg, and is labeled as to each circuit's identity. The circuit breaker panel contains all circuit protection devices resettable in flight. The circuit breakers have their rated values identified on the top of the shaft. The circuit breakers only have two positions, open and closed. In the open position the circuit is disconnected and in the closed position the circuit breaker will automatically open the circuit if an overload or circuit fault occurs. Each circuit breaker requires a manual reset by the operator. Avionics loads on the NON-ESSENTIAL Avionics Bus and ESSENTIAL Avionics Bus are protected by -amp AVIONICS circuit breakers connected to the respective bus through relays energized by the AVIONICS switch. In addition to the individual circuit breakers, -amp circuit breakers located in the Master Control Unit (MCU) protect the Main Distribution Bus and the Essential Distribution Bus. Additionally a -amp circuit breaker is located in the MCU to protect the landing light circuit. B. Switches BAT, BAT, ALT, and ALT master switches are side by side and directly in front of the pilot on the bolster panel. The BAT switch disconnects battery from the main bus in the MCU. The alternator switch disconnects the forward alternator (ALT ) from the main bus. If BAT and ALT switches are in the OFF position, the flight critical instruments will remain powered from ALT or BAT. If BAT and either ALT or ALT switches are turned to the ON position, the hour meter becomes activated. () BAT & ALT Master Switches -0 Page Apr 007
Note: Prior to engine start-up, the pilot must activate only the BAT switch to verify that BAT properly energizes the electrical loads powered by the ESSENTIAL Bus and that BAT has proper voltage. Serials 000 thru 60, 60 thru 6, 6 thru 66: The voltage is displayed by the combination Volt / Amp meter mounted on the RH instrument panel. Serials 60, 6, 66 & subs: The voltage is displayed by the MFD and PFD. Use BAT for suppling electrical power to the avionics system when performing general servicing tests. The rocker type electrical system MASTER switches are ON in the up position and OFF in the down position. The left battery switches, labeled BAT and BAT, control all electrical power to the airplane. The right switches, labeled ALT and ALT, control the corresponding alternator. Normally, all master switches will be on. However, the BAT switch can be turned on separately to check equipment while on the ground. To check or use avionics equipment or radios while on the ground, the avionics power switch must also be turned on. Positioning the ALT and ALT switch to the OFF position isolates the alternators from the electrical system and the entire electrical load is placed on the batteries. Note: Continued operation with the alternator switch off will reduce battery power low enough to open the battery relay, remove power from the alternator field, and prevent alternator restart. () Avionics Power Switch A rocker switch, labeled AVIONICS, controls electrical power from the airplane primary bus to the avionics bus. The switch is located next to the ALT, ALT, BAT, and BAT Master switches and is ON in the up position and OFF in the down position. Typically, the Avionics Power Switch is used to energize or de-energize all avionics on the Avionics Non-essential and Avionics Essential buses simultaneously. With the switch in the OFF position, no electrical power will be applied to the avionics equipment, regardless of the position of the master switch or the individual equipment switches. The AVIONICS switch should be placed in the OFF position prior to turning the master switch ON or OFF, starting the engine, or applying an external power source. The airplane has two different types of circuit protection devices. Each circuit has an electrical protective device, with the exception of the starter motor. A -amp clock fuse is located in the MCU and the push-pull type circuit breakers are all located in the cabin area. The fuses are not replaceable during flight. C. Transmission Wire Power is routed throughout most of the aircraft with MIL-W-79/6 teflon coated wires. These wires have a 0 C rating. Joints made in wires are covered with polyolefin heat shrink material, or are joined using a solder sleeve. In the engine compartment, all power wire terminal ring ends are covered with a silicon boot. Rubber, nylon, or teflon grommets protect the wires from chafing where the wires pass through materials that could cause wear. -0 Page Apr 007
. MAINTENANCE PRACTICES A. Circuit Breakers (See Figure -0) () Removal - Circuit Breakers (a) Verify ignition switch is in OFF position and remove the key. (b) Disconnect battery. (Refer to -0) (c) Disconnect battery. (Refer to -0) (d) Remove aft screws securing circuit breaker panel to center console. Swing circuit breaker panel open. (e) Identify and disconnect all wires to circuit breaker and/or bus. Note: It may be necessary to loosen more than one circuit breaker and/or bus bar to remove the selected breaker and/or bus bar. (f) Remove nut, washer, and tab washer securing circuit breaker to panel. Remove circuit breaker from airplane. () Installation - Circuit Breakers (a) Position tab washer on circuit breaker stud. (b) Position circuit breaker to panel, ensuring washer tab inserts into small hole on panel. (c) Install washer and nut securing circuit breaker to panel. (d) Identify and connect all wires to circuit breaker. (e) Position circuit breaker panel to center console and secure with screws. (f) Connect battery. (Refer to -0) (g) Connect battery. (Refer to -0) () Functional Check - Redundant Circuit Breakers 8 VDC for the HSI or PFD, turn coordinator, and attitude indicator is supplied through redundant circuit breakers on the essential bus and main bus. The following functional check ensures both circuit breakers are operating properly with no disturbance of power to the equipment. (a) Set BAT switch to ON position. (b) Serials 000 thru 7: Test HSI/PFD circuit breakers. Pull HSI/PFD # circuit breaker. Verify no disruption of power to HSI or PFD. Reset HSI/PFD # circuit breaker. Pull HSI/PFD # circuit breaker. Verify no disruption of power to HSI or PFD. 6 Reset HSI/PFD # circuit breaker. (c) Serials 8 & subs: Test PFD circuit breakers. Pull PFD # circuit breaker. Verify no disruption of power to PFD. Reset PFD # circuit breaker. Pull PFD # circuit breaker. Verify no disruption of power to PFD. 6 Reset PFD # circuit breaker. (d) Serials 000 thru 7: Test TURN COORD circuit breakers. Pull TURN COORD # circuit breaker. Verify no disruption of power to turn coordinator. Reset TURN COORD # circuit breaker. Pull TURN COORD # circuit breaker. Verify no disruption of power to turn coordinator. -0 Page Apr 007
(e) (f) (g) 6 Reset TURN COORD # circuit breaker. Serials 8 & subs: Test TRN CRD circuit breakers. Pull TRN CRD # circuit breaker. Verify no disruption of power to turn coordinator. Reset TRN CRD # circuit breaker. Pull TRN CRD # circuit breaker. Verify no disruption of power to turn coordinator. 6 Reset TRN CRD # circuit breaker. Test ATTITUDE circuit breakers. Pull ATTITUDE # circuit breaker. Verify no disruption of power to attitude indicator. Reset ATTITUDE # circuit breaker. Pull ATTITUDE # circuit breaker. Verify no disruption of power to attitude indicator. 6 Reset ATTITUDE # circuit breaker. Set BAT switch to OFF position. -0 Page Apr 007
B. Power Transient Voltage Suppressor (TVS) (See Figure -0) () Removal - Power TVS (a) Verify ignition switch is in OFF position and remove the key. (b) Disconnect battery. (Refer to -0) (c) Disconnect battery. (Refer to -0) (d) Remove aft screws securing circuit breaker panel to center console. Swing circuit breaker panel open. (e) Disconnect wires from power TVS. (f) Remove screws, washers, and nuts securing power TVS and terminal rings to circuit breaker panel. () Installation - Power TVS (a) Position power TVS and terminal rings to circuit breaker panel and secure with screws, washers, and nuts. (b) Connect wires to power TVS. (c) Position circuit breaker panel to center console and secure with screws. (d) Connect battery. (Refer to -0) (e) Connect battery. (Refer to -0) () Inspection/Check - Power TVS (a) Remove aft screws securing circuit breaker panel to center console. Swing circuit breaker panel open. Note: If a circuit breaker repeatedly opens and cannot be reset, the power TVS may be damaged. (b) (c) (d) (e) Reset circuit breakers. Visually inspect power TVS for charring, cracking, pieces broken off or missing, or other signs of physical damage. If necessary, replace power TVS. (Refer to -0) Serials 0 thru 080 w/ PFD, 08 & subs: Inspect fuses connected to PFD # and PFD # circuit breakers. Verify ignition switch is in OFF position and remove the key. Set BAT, BAT, and AVIONICS switches to OFF positions. Visually inspect fuses for condition. If fuse is blown, replace fuse and corresponding power TVS. (Refer to -0) Position circuit breaker panel to center console and secure with screws. -0 Page Apr 007
CIRRUS AIRPLANE MAINTENANCE MANUAL ESSENTIAL AVIONICS (REF) NON-ESSENTIAL AVIONICS (REF) PITOT HEAT (REF) Serials 0 thru 080 w/ PFD, 08 & subs. 6 LEGEND. Screw. Circuit Breaker Panel. Terminal Ring. Washer. Nut 6. Power TVS 6 Serials 000 thru 0, 0 thru 080 w/o PFD. SR_MM_B Figure -0 Circuit Breaker Panel (Sheet of ) -0 Page 6 Apr 007
7 8 9 CENTER CONSOLE (REF) 0 W66 WIRE HARNESS (REF) 7 LEGEND. Screw. Circuit Breaker Panel. Terminal Ring. Washer. Nut 7. Star Washer 8. Circuit Breaker 9. Bus Bar 0. Piano Hinge. Hinge Pin. Relay. Relay Socket. Clamp. Tab Washer SR_MM_B Figure -0 Circuit Breaker Panel (Sheet of ) -0 Page 7 Apr 007
C. Bolster Panel Switches - Serials 000 thru 08 (See Figure -0) () Removal - Bolster Panel Switches (a) Verify ignition switch is in OFF position and remove the key. (b) Disconnect battery. (Refer to -0) (c) Remove LH kick plate. (Refer to -0) (d) Remove screws and washers securing bolster panel to console. (e) Identify and disconnect all wires to switch. (f) Compress retainers on switch and push up to remove. () Installation - Bolster Panel Switches (a) Compress retainers on switch and push down into position. (b) Identify and connect all wires to switch. (c) Position bolster panel to console and secure with screws and washers. (d) Install LH kick plate. (Refer to -0) (e) Connect battery. (Refer to -0) D. Bolster Panel Switches - Serials 09 & subs The bolster panel switches are integral to the bolster panel. For maintenance practices pertinent to the bolster panel, see Electronic Panels and Multipurpose Parts. (Refer to -0) -0 Page 8 Apr 007
0 7 Serials 000 thru 08. 6 8 9 LEGEND. Knob. Nut. Washer, Star. Switch. Potentiometer 6. Socket Relay 7. Relay 8. Washer 9. Screw 0. Switch Panel, Forward Console. Bolster Panel SR_MM_B Serials 000 thru 08 Figure -0 Bolster Panel Switch Installation - Serials 000 thru 08-0 Page 9 Apr 007
E. Convenience Power Circuit Card (See Figure -0) () Removal - Convenience Power Circuit Card (a) Remove pilot s seat. (Refer to -0) (b) Remove left aft console trim. (Refer to -0) (c) Disconnect wiring harnesses from connectors on convenience power circuit card. (d) Remove screws and washers securing convenience power circuit card to bracket. () Installation - Convenience Power Circuit Card (a) Install screws and washers securing convenience power circuit card to bracket. (b) Connect wiring harnesses to connectors on convenience power circuit card. (c) Perform Functional Test - Convenience Power Circuit Card. (Refer to -0) (d) Install left aft console trim. (Refer to -0) (e) Install pilot s seat. (Refer to -0) () Functional Test - Convenience Power Circuit Card (a) Acquire necessary tools, equipment, and supplies. Description P/N or Spec. Supplier Purpose Voltmeter - Any Source Measure voltage. (b) (c) (d) (e) (f) (g) (h) (i) (j) (k) (l) (m) (n) (o) (p) (q) (r) (s) (t) Ensure flap switch is set in current flap position. Ensure that all flight controls and propeller area are clear. Pull Starter Relay and Fuel Pump Relay circuit breakers. Connect 8 ± VDC external power to external power receptacle. Set BAT switch to ON position. Use voltmeter to ensure voltage measures -6 VDC. Ensure Flap circuit breaker is in. Ensure Flap Position lights are not on. Set BAT switch to ON position. Set BAT switch to OFF position. Ensure OIL, ALT, and ALT annunciator lights indicate power. Use voltmeter to ensure voltage at convenience power outlet measures ± VDC with positive pin (+) to center contact and negative pin (-) to outside of jack. On convenience power circuit card, set headset power switch S0 to 9 VDC. Ensure voltage at all four ANR jacks measures 9 ± VDC with positive (+) to center contact and negative (-) to ground. On convenience power circuit card, set headset power switch S0 to 7 VDC. Ensure voltage at all four ANR jacks measures 7 ± VDC with positive (+) to center contact and negative (-) to ground. On convenience power circuit card, set headset power switch S0 to 8 VDC. Ensure voltage at all four ANR jacks measures VDC with positive (+) to center contact and negative (-) to ground. Leave power switch set at 8 VDC. -0 Page 0 Apr 007
8 8 8 8 CIRRUS AIRPLANE MAINTENANCE MANUAL SPAR TUNNEL (REF) S0 9 R CIRRUS DESIGN CORP. R7 CR R6 U J7 6 C C9 CR R8 C0 C8 U R9 PCB 9- REV CCA 06- REV POSITION HEADSET POWER SYSTEM VOLTAGE (8V) POSITION HEADSET POWER = 7V POSITION HEADSET POWER = 9V LEGEND. Heat Sink. Screw. Washer. Bracket. Nut CONVENIENCE POWER CIRCUIT CARD ASSEMBLY S0 SWITCH POSITION DETAIL SR_MM_09 Figure -0 Convenience Power Circuit Card Installation -0 Page Apr 007
Intentionally Left Blank -0 Page Apr 007