As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE CRUISING AT FL230 WE GOT A "GEAR NOT DOWN" CAS MESSAGE ALONG WITH THE GEAR WARNING HORN AND THE RT PFD AIRSPEED INDICATOR TURNED RED. RECEIVED ALL NORMAL INDICATIONS ONCE GEAR WAS DOWN & LOCKED. TROUBLESHOT TO A BAD FLAP/SLAT ECU. REPLACED WITH AN INSPECTED/TESTED FSECU. FUNCTIONAL TEST AND LANDING GEAR EXTENSION WARNING SYS OPS CHECKED GOOD. WORK DONE IAW MM 27-51-05, 27-51-45 & 32-60-00.