As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 6522 - IAD-RIC - DURING TAKEOFF, AIRCRAFT MADE AN UNSCHEDULED LANDING DUE TO HYDRAULIC PSI FELL BELOW LIMITS AFTER GEAR RETRACTION. AIRCRAFT RETURNED TO GATE WITH NO FURTHER PROBLEMS. MAINTENANCE INSPECTED AND SERVICED HYDRAULIC SYSTEM, OPS CHECK OK. AIRCRAFT WAS RELEASED AND APPROVED FOR RETURN TO SERVICE. (M)