DA-42 NG: Electrical SystemTechnical Specific — DGCA CPL practice questions

All 12 questions — DA-42 NG: Electrical System

Technical Specific · DGCA CPL. The correct option is marked on each.

1. Q1. The aircraft electrical system is:

   • A.14 V DC
   • B.24 V DC
   • C.28 V DC✓
   • D.115 V AC

   Why: 28 V DC.

2. Q2. The rating of each alternator is:

   • A.40 A
   • B.60 A
   • C.70 A✓
   • D.90 A

   Why: One belt-driven alternator on each engine.

3. Q3. The main battery is rated at:

   • A.12 V, 7.2 Ah
   • B.24 V, 13.6 Ah✓
   • C.28 V, 20 Ah
   • D.24 V, 40 Ah

   Why: Mounted in the front baggage compartment area.

4. Q4. In the event of a complete aircraft electrical failure, the ECU backup batteries will keep the engines running for approximately:

   • A.10 minutes
   • B.20 minutes
   • C.30 minutes✓
   • D.60 minutes

   Why: After which both engines may stop. Treat a double alternator failure as a "land within 30 minutes" emergency.

5. Q5. With the EMERGENCY switch ON, the emergency battery supplies the standby instrument and flood light for at least:

   • A.30 minutes
   • B.1 hour
   • C.1.5 hours✓
   • D.3 hours

   Why: It is a non-rechargeable dry battery, independent of all other consumers.

6. Q6. The minimum and maximum system voltages are:

   • A.24.1 V and 32.0 V✓
   • B.28.0 V and 30.0 V
   • C.22.0 V and 28.0 V
   • D.25.0 V and 34.0 V

   Why: The red arc on the voltage indication begins at 24.1 V.

7. Q7. The maximum permitted alternator load (amperage) is:

   • A.50 A
   • B.60 A
   • C.70 A✓
   • D.90 A

   Why: Exceeding it triggers the L/R ALTN AMPS warning.

8. Q8. The caution L/R VOLTS LOW is displayed when bus voltage falls below:

   • A.22 V
   • B.24 V
   • C.25 V✓
   • D.28 V

   Why: 25 V.

9. Q9. The caution L/R ALTN FAIL indicates:

   • A.The left or right alternator has failed✓
   • B.The battery has failed
   • C.The starter is engaged
   • D.The avionics master is off

   Why: The left or right alternator has failed.

10. Q10. Which bus is connected directly to the main battery and cannot be switched off?

    • A.The avionic bus
    • B.The hot battery bus✓
    • C.The main bus
    • D.The ECU bus

    Why: It supplies the pilot map/reading light and the ELT unit.

11. Q11. The avionic bus is connected to the right main bus through:

    • A.The ELECT. MASTER switch
    • B.The AVIONIC MASTER switch✓
    • C.The ENGINE MASTER switch
    • D.A permanent link

    Why: The AVIONIC MASTER switch.

12. Q12. The external power socket accepts:

    • A.14 V DC
    • B.28 V DC✓
    • C.115 V AC
    • D.24 V AC

    Why: Located on the lower surface of the nose section, with a diode protecting against reverse polarity.