As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTS NR 1 START SWITCH MADE LOUD POPPING NOISE WITH SPARKS. [SUP 05-16-07] INCORRECT INSTALLATION. THE WIRING FROM THE SWITCH WAS PINCHED BETWEEN THE SWITCH AND THE PANEL, RATHER THAN PROPERLY ROUTED BEHIND THE SWITCH. REPLACED START SWITCH, DAMAGED WIRES, AND DAMAGED INSULATION.