Repaso Semana 2 Boeing 777

What is the primary function of the electrical power system on the Boeing 777?. Only generate AC power. Manage only DC power and batteries. Make, supply, and control electrical power to the airplane.

Which of the following are the five main power sources?. Two IDGs, APU generator, primary external power, secondary external power. Two backup generators, RAT, main battery, APU battery. Left and right GCUs, BPCU, EEUs.

What is the continuous supply capacity of each IDG?. 20 kVA. 90 kVA. 120 kVA.

What is the continuous supply capacity of each backup generator?. 120 kVA. 90 kVA. 20 kVA.

What is the continuous supply capacity of the RAT generator?. 20 kVA. 7.5 kVA. 120 kVA.

The main battery is rated at: 47 Ah. 90 Ah. 20 Ah.

Which six electronic units control the AC power sources?. Left GCU, Right GCU, Backup generator converter, APU GCU, BPCU, RAT GCU. EEUs only. ELMS panels only.

All airplane electrical power goes through which system for distribution?. GCUs only. ELMS panels. RAT GCU.

The ELMS panels include: Only P5 and P61. P100, P200, P300, P110, P210, P310, P320. Only E1–E4 racks.

Main and backup power go to the left, right, or auxiliary power panels, which supply: Only small loads (< 25 A). Large loads (usually 25 A or more). Only the RAT generator.

The electrical power system normally operates as: One single channel. Three independent channels. Two independent power channels.

Buses on the left channel include: Right main AC, right utility, right transfer, right DC. Left main AC, left utility, left transfer, left DC, standby AC, captain’s flight instrument, battery, Battery #2. Only ground service and hot battery.

Primary external power automatically supplies power to the: RAT generator. Left main AC bus only. Ground handling bus.

When secondary external power is connected for additional capacity: The right BTB opens so secondary supplies the left side and primary supplies the right side. Both BTBs close permanently. The APU generator is automatically disconnected.

The IDGs normally supply electrical power when: The engines are operating. The airplane is on the ground only. Only during autoland.

Backup generators are: Battery-powered only. Constant-speed, constant-frequency. Variable-speed, variable-frequency.

Each backup generator contains permanent magnet generators (PMGs) that are the primary power sources for: The FCDC PSAs. The main battery only. The APU generator.

If all normal power is lost, the RAT generator can supply the flight instrument buses through: The left and right TRUs only. The two center TRUs. The main battery charger only.

If the RAT generator does not operate, the main battery supplies power to: Only the right main AC bus. Only the hot battery bus. The battery buses, captain’s flight instrument bus, and the standby AC bus.

The four battery buses are: Left DC, Right DC, Center DC, Flight instrument. Main AC, Transfer, Utility, Standby. Hot battery, Battery, Battery #2, APU battery.

Three FCDC PSAs supply power to the flight control system. Each PSA has: Only RAT power. No backup power. A small battery to prevent power interruptions during power transfers.

The electrical panel is located on: Door 2 left. The P61 overhead maintenance panel only. The P5 overhead panel.

The battery switch connects the hot battery bus to: The APU battery bus. The ground service bus. The Battery #2 bus.

The APU generator switch: Controls only the RAT. Is normally left OFF. Left ON.

Bus tie switches are normally left in: ISLN. AUTO. OFF.

Generator control switches are normally left: In ISLN. OFF. ON.

Drive disconnect switches: Control the backup generators. Connect the IDG to the gearbox. Remove engine gearbox power from the IDG.

The standby power switch has three positions: ON, OFF, AUTO. PRI, SEC, OFF. OFF, AUTO, BAT.

The electrical synoptic display shows green flow segments for: Fault conditions only. Electrical power flow. Only battery voltage.

On the electrical synoptic, a white box indicates: A fault exists. Power source is on or breaker is closed. Power source is off or the breaker is open.

An amber box and X on the synoptic indicate: Normal operation. A fault with the power source or breaker. Battery charging.

When ELMS performs a load shed, the message that appears is: ISLN. GEN OFF. LOAD SHED.

Electrical Maintenance Page 1 shows information on: Only bus status (ON/OFF). Only component locations. AC generation, DC generation, generator oil information, FBW output, and auto-event messages.

On Maintenance Page 1, AC generation indications include: Only oil level. Voltage, frequency, and load. Only voltage.

Generator oil information on Maintenance Page 1 includes: Only frequency. Oil outlet temperature, oil rise temperature, oil level, and oil filter message. Only voltage.

Electrical Maintenance Page 2 shows: Oil temperatures only. Only external power status. Which buses are receiving power.

The ELMS has two basic independent functions: Only power generation. Only battery charging. Physical container for electrical equipment and a control system.

EEUs control and monitor load-switching devices in their related ELMS panels, but: Control every single load-switching device. Control only the RAT. Do not control all large load-switching devices.

EEUs receive data from other electrical power control units and airplane systems: Only via discrete signals. Directly. Only from the main battery.

Most electrical system components are located in: Only the wing-to-body fairing. The main equipment center. The flight deck only.

The RAT generator is located in the: E10 rack. Main equipment center. Wing-to-body fairing aft of the right main gear.

The APU generator attaches to the: E5 rack. APU gearbox. Engine main gearbox.

IDG and backup generator air-oil heat exchangers are located: In the flight deck. In the E1 rack. Under the inner liner of the engine intermediate case.

The external power panel is located:. In the E10 rack. To the right of the main equipment center access door. On the P5 overhead panel.

The ground service switch is located: On the P5 panel. the main equipment center. On the flight attendant’s panel.

The towing power system: Is controlled automatically by the ELMS at all times. Supplies power to all airplane systems. Supplies power only to components necessary to safely tow the airplane.

On the electrical synoptic, the amber word “DRIVE” indicates. Backup generator is online. The related IDG has low oil pressure. Normal IDG operation.

Green boxes on the synoptic indicate: Fault conditions. Load shed active. Power source is on.

The left channel also supplies power to: Only the right FCDC PSA. The left and center flight controls. Only the APU battery.

The right channel also supplies power to: Only the captain’s flight instrument bus. The left and center FCDC PSAs. The right FCDC PSA.