As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GEAR DISAGREE ON APPROACH, BOTH MAINS NOT DOWN AND LOCKED. WO#336473. PERFORMED CRJ200 LANDING GEAR HEALH CHECK FOUND MLG SELECTOR VALVE BAD. REMOVED AND REPLACED MLG SELECTOR VALVE IAW AMM 32-30-10. LEAK & OP CHECK GOOD. OK FOR SVC. THIS CLEARS WO#336473.