Main Bus Voltage while Starting Engine

There’s some debate on whether avionics should be on during engine start. The concern seems to be voltage transients due to engaging and disengaging large solenoids and the starter motor. I captured this at ~40kHz and don’t see any potentially dangerous transients in this nominal engine start.

I suspect the dips until 1 second are due to higher torque during the compression strokes before engine started running. I continued to hold the start button until ~2.5 seconds. You can see some periodic noise that I believe is due to the secondary ignition coils charging.

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