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VIKG • PA-28-181 DX
Back to PA-28 Archer DX Technical Deck
VIRTUAL COCKPIT SYSTEMS LAB • LIVE SIMULATION
Dedicated PA-28 Cockpit Simulator & Systems Lab

PA-28-181 Archer III DX (Continental TAE 125-02-114)

Overhead panel follows the exact POH sequence: Starter → (Battery Master, Fuel Pump, FADEC Test) → (Alternator, Force B) → (Landing, Nav, Strobe) → (Emergency Battery, Avionics Master). Every switch clearly identifies its guard status (Guarded OFF, Guarded ON/ARM, or Unguarded).

PA-28 Overhead Panel Sequence & Switch Guard Architecture
Live Engine Status:COLD & DARK
1. STARTERSPRING-LOADED
STARTERSTART → RUN
Guard: UnguardedOFF
2. PRIMARY & FUEL3 UNGUARDED
3. GEN & ECU🔒 1 GUARDED OFF
FORCE B🔒 Guarded OFF
4. LIGHTING3 UNGUARDED
5. EMERG & AVIONICS🛡️ GUARDED ON & 🔒 OFF
EMERG BATT🛡️ Guarded ARM
FADEC BACKUP🔒 Guarded OFF
FUEL SELECTOR VALVE:VALVE CLOSED (STARVATION)
CABIN HEAT & DEFROST:PUSHED IN (CLOSED)
PITOT HEAT:OFF / UNPOWERED
MAIN BUS VOLTAGE0.0 V
BUS LOAD (AMPS)0 A
ENGINE CRANKSHAFT0 RPM
ACTIVE FADEC CHANNELECU A (AUTO)
FUEL PRESSURE0.0 Bar
COOLANT TEMP28 °C
Electrical Failure Simulation & Live Power Source Matrix

Select an electrical failure to observe which system is feeding electricity to each bus and FADEC ECU in real-time.

CURRENT ACTIVE ELECTRICAL POWER SOURCE:
NO POWER SOURCE ONLINE — TOTAL ELECTRICAL BLACKOUT
ENGINE STOPPED (COLD & DARK)
REAL-TIME POWER FEEDING PIPELINE:
Alternator (DEAD)+Main Battery (LOST)+FADEC Backup (DEAD / OFF)NOTHING IS RECEIVING POWER → 💥 ENGINE HAS FAILED (FLAMEOUT)!
1. 28V Main Electrical Bus0.0V • DEAD

DEAD (0.0V): Both Alternator and Main Battery are offline. Main bus loads are unpowered.

Loads: Lights, booster pump, cabin/pitot heat, starter
2. Essential Flight BusEMERG BATT FEED

Fed by Standby Emergency Battery. Maintains flight guidance on standby attitude indicator (ESIS).

Loads: Standby attitude (ESIS), COM1 standby, flood lighting
3. Garmin G1000 NXi AvionicsSCREENS DARK

DARK SCREENS: Main Bus lost or Avionics Master switch is OFF. Pilot must navigate via Standby Horizon (ESIS).

Avionics load: ~12 Amperes on 28V bus
4. Standby Attitude (ESIS)SELF-BUFFERED (60M)

Powered by Essential Bus during normal flight, and backed up by its own dedicated 60-minute emergency battery during total electrical blackout.

⚠️ Note: Standby battery powers ESIS ONLY; it does NOT feed the engine FADEC!
5. FADEC Dual ECU ModuleUNPOWERED (0V)

NO ELECTRICAL POWER: Both ECUs are dead. Common-rail fuel injection cannot fire.

Active Channel: ECU A (PRIMARY)
6. TAE 125 Engine CombustionSTOPPED

Engine is shut down in Cold & Dark state.

0 RPM • 0 Bar
Alternator:OFFLINE / INOPMain Batt:DISCONNECTEDFADEC Backup:READY (30M)
ALTERNATOR28V / 70A (TAE 125)MAIN BATT24V / 13.6 AhFADEC BACKUPDedicated 24V 13.6AhISOLATED EMERGENCYMAIN 28V BUS (0.0V)DUAL FADEC MODULEECU ASTANDBYECU BSTANDBYEMERGENCY PATH: POWERS ECU A DIRECTLY (30 MINS)GARMIN G1000 NXiDARK (STANDBY FLIGHT INSTRUMENT ONLY)STANDBY ATTITUDE (ESIS)EMERGENCY BATTERY FEED (60 MINS)
5-Battery Redundancy Architecture

Because common-rail diesel injectors require continuous electricity to pulse fuel into the combustion chambers, the Archer DX provides five independent battery buffers:

  • Main Battery (24V 13.6Ah): Powers the main 28V bus, starter motor, and flight deck systems.
  • FADEC Backup Battery (24V 13.6Ah): Isolated under a red safety guard. Powers ECU A exclusively for 30 minutes in total blackout!
  • Standby Instrument Battery: Powers the standby attitude indicator (ESIS) for 60 minutes.
  • Two Internal ECU Buffer Batteries: Prevent micro-second voltage transients inside ECU A & B.
DGCA Examiner Viva Distinction

"Does the Emergency Battery power the engine FADEC?"
NO! The Standby Instrument Emergency Battery powers the gyro horizon ONLY. Engine FADEC fuel metering is backed up strictly by the dedicated FADEC Backup Battery.

Overhead Panel Sequence & Guards

5 Cockpit Switch Groups & Guard Rules

  1. 1. Starter: Unguarded (Spring-Loaded). Start key springs back from START to RUN.
  2. 2. Primary Power & Fuel: (Battery Master, Fuel Pump, FADEC Test). Battery & Pump are Unguarded; FADEC Test is Momentary Push.
  3. 3. Gen & ECU: (Alternator, Force B). Alternator is Unguarded; Force B is GUARDED OFF.
  4. 4. Exterior Lighting: (Landing, Nav, Strobe). All 3 switches are Unguarded.
  5. 5. Emergency & Avionics: (Emergency Battery, FADEC Backup, Avionics Master). Emerg Batt is GUARDED ON/ARM; FADEC Backup is GUARDED OFF; Avionics is Unguarded.
Electrical Emergency Rules

Alternator Fail vs Total Blackout

CASE 1: ALT INOP (Alternator Offline)

Main battery powers flight instruments for 30–45 mins. Turn off Pitot Heat, Aux Pump, and Strobes to extend battery life. Divert to nearest suitable airfield.

CASE 2: DUAL BLACKOUT (G1000 Dark)

Lift the red guard and flip the FADEC BACKUP BATTERY switch ON immediately! This isolated 24V battery powers ECU A directly for 30 minutes, keeping the common-rail fuel injection operating.

DGCA Viva Exam Focus

Technify TAE 125 Key Facts

  • Why heated fuel return? Common-rail pressurization heats fuel to >60°C. Surplus unburned fuel recirculates back to warm the active tank, preventing paraffin wax crystallization in winter or high altitudes.
  • Why liquid cooling? Liquid cooling prevents thermal shock during rapid descents and provides a safe cabin heating matrix with zero carbon monoxide hazard.
  • How many batteries? 5 batteries total: Main 24V 13.6Ah, FADEC Backup 24V 13.6Ah, ESIS Standby Emergency 60-min, and 2 internal ECU buffer batteries.