Electrics

The F-4E derives electrical power from a pair of AC generators driven by the J79 engines, a pair of AC to DC transformers, and a battery for electrical functions with the engines offline. In addition, the Phantom II can receive external electrical power from ground crew. The two generator arrangement, while normally working independently, includes a bus tie that can connect both buses together to draw power from a single generator in case of failure.

Generator Indicator Lights

GenInd

Three warning indicators are found on the generator indicator panel: LH GEN OUT, RH GEN OUT, and BUS TIE OPEN. The respective GEN OUT warning will illuminate in the event the generator in question fails. The indication of BUS TIE OPEN is an acknowledgement that a single functioning generator is providing power to the entire aircraft. In the event of a generator failure, the Master Caution will also illuminate. However, in case both generators fail, no GEN OUT light will illuminate.

Generator Control Switches

GenCtl

A pair of Generator Control Switches are found on the right console, one for each engine. These three position switches - ON (Forward), OFF, ON External (Aft) - control the state of each respective generator. In the event of a possible generator failure, selecting OFF for the generator that is believed to be offline will cause the power bus to provide electricity from the remaining generator to the other half of the electrical system. The External On setting is used for ground handling purposes when connected to external power, and provides electric power to all instruments, except the CNI and the AFCS.

Instrument Ground Power Switch

InstrumentGroundPowerSwitch

Power from an external source to the instrument buses (115/200 volt ac, 28 volt ac, and 14 volt ac), can be provided by the Instrument Ground Power Switch (1) (if the generator switches are set to EXT ON), found on the right wall in the rear cockpit. Once external electrical power is disengaged or an engine generator comes online, it will switch off.

Bus System

manual_electric_system_diagram

The battery and generators power several buses which then route current to the relevant systems:

Left Main AC Bus
Right Main AC Bus
Instrument AC Bus
Warning Light AC Bus
Main DC Bus
Essential DC Bus
Armament DC Bus
Battery Bus

Circuit Breakers

From the buses, power is first routed through Circuit Breakers before they reach the actual systems.

💡 Due to engine limitations, CBs in the WSO cockpit are currently not accessible.

Most circuit breakers are placed in the WSO pit on either wall, with the exception of one panel in the pilot pit, housing breakers for the flight control surfaces and similar crucial systems.

Pilot Panel

pilot_cb_panel

Located on the right wall of the pilot cockpit, this panel contains seven circuit breakers responsible for flight control surfaces and other systems important for safe operation of the aircraft.

AIL Feel-Trim (1)
STAB Feel-Trim (2)
Speed Brake (3)
Landing Gear (4)
Flaps (5)
Trim Controls (6)
Rudder Trim (7)

Lighting Panel

pilot_light_cbs

Hidden behind a bundle of cables to the right of the telelight panel in the Pilot cockpit are two circuit breakers controlling lights.

The upper one (1) is responsible for powering the primary instrument lights, while the lower (2) circuit breaker powers all indicator and warning lights.

CB Panel 1

WSO CB Panel 1

Front section of right wall in WSO cockpit.

Has the circuit breakers for all stations, the armament and weapon system.

CB Panel 2

WSO CB Panel 2

Center section of right wall in WSO cockpit.

Mostly responsible for Engine and Hydraulics operation.

CB Panel 3

WSO CB Panel 3

Aft section of right wall in WSO cockpit.

Contains breakers for auxiliary functions, such as Anti-Icing or the Arresting Hook.

CB Panel 4

WSO CB Panel 4

Aft section of left wall in WSO cockpit.

Master controls of power coming through all buses, the flight computer and targeting pod.

CB Panel 7

WSO CB Panel 7

Next to the right rudder pedal in WSO cockpit.

Hidden behind a cover, this panel houses all breakers for the ECM and Jamming equipment.

Failures and Emergency Power Distribution

In the event of damage to the Airplane and loss of either the left and/or right generator, as well as the Main 28 Volt DC Bus there are several different systems that are inoperative for the respective bus.

Left Hand Generator Out - Bus Tie Open

If the left-hand generator stops working the following systems won't work:

Critical Systems	Non-Critical Systems
Anti-Ice System	AN/ARW 77 (Used to fire AGM-12 Bullpup)
Anti-Skid System	Anti-Collision Light (one filament)
Afterburner Ignition	DSCG
INS Heater	ECM Pods
Landing light	Equipment cooling (e.g. Pave Spike)
	Fuselage lights
	Front Cockpit console lights
	Front Cockpit red instrument floodlights (DIM)
	Lead Computing Optical Sight
	Left-hand 28V Transformer
	Left-hand fuel boost pump
	Left-hand missile firing
	Left-hand missile power
	Left-hand transformer rectifier
	No. 4 Electrical fuel transfer pump
	Nose gun
	Radar
	Radar Scope Camera
	Red console floodlights
	Right-hand missile power
	Seat adjust
	AGM-45 Shrike guidance
	Target designator (Pave Spike)
	Utility light
	Utility Power AC
	Wing and Tail light DIM
	WRCS Power

Right Hand Generator Out - Bus Tie Open

If the right-hand generator stops working the following systems do not work:

Critical Systems	Non-Critical Systems
Airspeed Pitot Heater	ADF
AOA Probe Heater	Aileron feel trim
Bellmouth Pitot Heater	Aileron rudder interconnect
Cockpit heat and venting	ALR-46 Radar Warning System
Fuel quantity indicator	Altitude Encoder
IFF	Anti-Collision light (one filament)
Rear cockpit ci heading pointer	APR-36/37 Radar Receiver
TACAN	APX 80 Air-to-Air IFF
VOR: Bearing Pointers	Armament power
	Autopilot
	Auxiliary receiver
	CADC
	ECM Pods
	Formation lights
	Front cockpit instrument lights
	Gunsight Camera
	In-Flight-Refuel (IFR) receptacle floodlights
	Left Engine ramp control
	No.6 Electric fuel transfer pump
	Oxygen Gage
	Radar altimeter
	Right Engine ramp control
	Right-hand 28V transformer
	Right-hand fuel boost pump
	Right-hand transformer rectifier
	Stability augmentation
	Taxi light
	Windshield temp sensing
	Wing and Tail Light BRT

Main 28 Volt DC Bus Out

If the Main 28 Volt DC Bus stops working the following systems do not work:

Critical Systems	Non-Critical Systems
Anti-Skid	ACM IN-RANGE and SHOOT lights
Bus Tie Relay (BUS TIE OPEN light ON)	ADF
Cockpit heat and venting	Aileron Rudder Interconnect
Internal wing fuel dump	Airborne Video Tape Recorder (AVTR)
Landing and Taxi lights	ALE-40 Countermeasure Dispenser
Nose Wheel Steering	Altimeter Vibrator
TACAN	APR-36/37 Radar Receiver
Turn & Slip Indicator (Rear Cockpit)	APX 80 A/A IFF
	Arresting Hook (only the up operation)
	AUX Air doors
	AUX receiver
	Conventional Weapons Release
	Combat Documentation Cameras
	DSCG
	ECM Control
	ECM Pods
	Engine Variable Bellmouth
	Equipment cooling control
	Fuselage, Anti-Collision and Tail lights
	Gunsight Camera
	Lead Computing Optical Sight
	Left-hand fuel boost pump
	Missile firing
	No.4 Electrical fuel transfer pump
	No.6 Electrical fuel transfer pump
	Nose Gun
	Pneumatic compressor
	Radar
	Radar Altimeter
	Rain Removal
	Radar Scope Camera
	Right-hand Fuel boost pump
	Rudder Trim/Bellmouth control
	Speed brake
	Special Weapons Centerline Interlock Arm
	Station select and Station select lights
	Stabilator Position indicator
	Target Designator (Pave Spike)
	Utility power
	VGH Recorder Power
	Walleye indent power
	Warning lights (DIM)
	WRCS Power

Battery Power Only

If only Battery Power is available the following systems will still work:

Critical Systems	Non-Critical Systems
AOA Indicator	All Stores EMER jettison
EGT Indicators	AOA Aural Tone Generator
Ejection Light	Fuel Control
EMER Attitude Indicator	Fuel Valve Power
Engine Fire and Overheat Detection (Test Functions)	Front Cockpit Instrument Floodlights (BRT)
External Wing Fuel transfer (Control)	Guard Receiver
Flaps/Slats control	KY-28
Flaps/Slats Position Indicator	Missile Fairing
Fuel Quantity Indicator	Missile Jettison
In-Flight-Refueling	Nozzle Position Indicator
ILS: CDI, Glide Slope Indicators, Audio, Marker Beacon	Outboard Station jettison
Intercom	Special Weapons Centerline Interlock Safe
Internal Wing Fuel transfer (Control)	Special Weapons Unlock
Landing Gear Control	Trim Control
Landing Gear Position Indicator
Left and Right Main Ignition
Stabilator Feel Trim
VOR: CDI, TO-From and Audio
White Flood light

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