It will be interesting to hear what caused the problem. Presumably the plane returned because the gear did not retract properly after takeoff. Subsequently the right wing gear did not extend properly. Probably fouled on a gear door.
The 747 undercarriage system has a lock that stops the gear lever from being raised. The lock will clear when the main gear is tilted and the air/ground switches are happy it is in the air with the steerable body gear aligned.The flight crew are able to override the lock once airborne if it does not release as a way of getting the gear up. I seem to remember they suggested using a pen to move the latch to stop your finger getting trapped. However if the gear are not in the correct position when manually overriding the lock and raising the gear this can lead to the gear jamming and graunching against the gear doors. Interesting to know if the crew had to override the gear lock once airborne.
Apart from the Pan Am incident in SFO Where the aircraft was badly damaged by hitting the opposite end light stanchions on takeoff jamming some of the gear I cannot remember any other incident where a 747 has failed to get a main gear down. At least it did not sit on its tail like the Pan Am.
Does anyone know of any other incident where a 747 could not get a main gear down?