As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHEN NOSE LIGHTS SWITCH TURNED OFF AFTER T/O, SPARKS FLEW FROM SWITCH UNIT. C/BS STAYED IN, BUT WERE PULLED BY CREW. FOUND JAM NUT LOOSE ON NOSE LIGHTS SWITCH CAUSING TERMINAL TO CONTACT METAL SUPPORT STRUCTURE. SECURED JAM NUT. CYCLED SWITCH SEVERAL TIMES, NO DEFECTS NOTED.