New York-bound Flight EI-105 took off from Dublin Airport and almost immediately reported a technical issue with the landing gear.
The pilot informed controllers on the ground that the gear would not retract, so he requested permission to enter a holding pattern over the Irish Sea while the crew attempted to resolve the problem.
The pilot once again radioed air control shortly afterwards to inform them that he intended to land at Dublin, and the plane returned to airport safely about 30 mins after departure.
Engineers are working on the plane to diagnose the cause of the problem.