As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB OUT AT 21000 FT, RECEIVED AVIONICS SMOKE WARNING. ACCOMPLISHED ECAM & CHECKLIST PROCEEDURES. DIVERTED. NOTED 13WA SMOKE DETECTOR FOR THE COCKPIT WOULD NOT TEST ON ARRIVAL. R & R THE SMOKE DETECTOR IAW AMM 26-15-12-0401. OPS CHECKED NORMAL, WITH NO ALERTS.