If DC external power is used for the start, which condition about the spike suppression and AVIONICS switches is required?

If DC external power is used for the start, which condition about the spike suppression and AVIONICS switches is required?

• A. External power not connected
• B. Spike suppression is not required
• C. AVIONICS switches can be moved to DACS before energizing power
• D. External power connected and energized with the spike suppression switch in START PROTECTION position prior to moving the AVIONICS switches to DACS

Answer: (D)

When starting with DC external power, the system must be protected from power transients that occur as power is applied. The spike suppression feature has a START PROTECTION position that should be engaged while the external power is connected and energized so the protective circuitry can limit inrush and voltage spikes before any avionics loads are connected. The correct sequence is to connect and energize external power with the spike suppression switch in START PROTECTION, then move the AVIONICS switches to DACS. This keeps the avionics safe from transient surges by ensuring the spike suppression path is active before the avionics bus is energized. If you move the AVIONICS to DACS before engaging spike suppression, or without external power energized, transient spikes can reach the avionics, potentially tripping breakers, causing faults, or damaging sensitive equipment. The options suggesting the spike suppression isn’t needed or that AVIONICS can be switched before energizing power don’t provide that necessary protection.

When starting with DC external power, the system must be protected from power transients that occur as power is applied. The spike suppression feature has a START PROTECTION position that should be engaged while the external power is connected and energized so the protective circuitry can limit inrush and voltage spikes before any avionics loads are connected.

The correct sequence is to connect and energize external power with the spike suppression switch in START PROTECTION, then move the AVIONICS switches to DACS. This keeps the avionics safe from transient surges by ensuring the spike suppression path is active before the avionics bus is energized.

If you move the AVIONICS to DACS before engaging spike suppression, or without external power energized, transient spikes can reach the avionics, potentially tripping breakers, causing faults, or damaging sensitive equipment. The options suggesting the spike suppression isn’t needed or that AVIONICS can be switched before energizing power don’t provide that necessary protection.