What was found
ON FLIGHT 3918 (DTW - CWA) FLAPS FAIL CAUTION OCCURED WHEN FLAPS WERE SELECTED TO 30 AT APPROX 175 KIAS ON APPROACH INTO CWA). AIRCRAFT LANDED SAFELY. PERFORMED TROUBLESHOOT PER BOMBARDIER FIM REV 44 IAW AD2009-06-12 PARA H, 6, I AND PA AD27-052J. LEFT BPSU CREATING HEAT DURING STEP 6 OF TROUBLESHOOT PER FIM 27-50-00 TROUBLE 7. REMOVED AND REPLACED LEFT BPSU IAW AMM 27-51-10. ALSO RE-RIGGED RIGHT BPSU IAW AMM 27-51-10. FAIL CODES WERE 1-BINDING 2-FECU 3-FLAP CONTROL LEVER. CODES WERE 5-1B, 5-2B, 16-1A, 16-2A, 25BC, 30BC, 33BC.