As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
A-SYSTEM HYDRAULIC LOSS AFTER T/O DURING FLAP RETRACTION. AIR TURN BACK TO SDF. ALL CKLISTS ACCOMPLISHED. FOUND NR 4 SLAT ACTUATOR SWIVEL SPRING RETAINER BLOWOUT AND O-RINGS CAUSING MASSIVE LEAKAGE. REMOVED AND REPLACED NR 4 SLAT ACTUATOR PER MM 27-81-01. OPS CKS GOOD.