As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT MAIN LANDING GEAR DID NOT EXTEND INITIALLY ON APPROACH TO TUS. RECEIVED ASSOCIATED GEAR DISAGREE MESSAGE. AFTER 15 SECOND DELAY THE LANDING GEAR EXTENDED AND ALL THREE GEAR LIGHTS INDICATED GREEN. JACKED AIRCRAFT AND PERFORMED LANDING GEAR EXTENSION AND RETRACTION TEST AS PER CRJ MM 32-30-00. CYCLED GEAR 7 TIMES, NO DEFECTS NOTED.