As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAKEOFF OUT OF MEM, WHEN THE LANDING GEAR WAS SELECTED UP THE MAIN PNEUMATIC SYSTEM WENT TO ZERO. THE LANDING GEAR WOULD NOT RETRACT. THE CREW DECLARED AN EMERGENCY AND RETURNED TO MEM. THE AIRCRAFT LANDED WITHOUT ANY OTHER PROBLEMS.