On 21 December 2023, a Boeing 737-800 experienced a flap load protection response to turbulence during a night go-around at Billund which locked the flaps in a mid-range position. A diversion to Copenhagen was commenced but when it became clear that the fault would result in landing with slightly below minimum reserve fuel, a MAYDAY was declared. The flight was completed without further event. It was concluded that flap system locking had probably resulted from the crew’s manual selection of 15° flap just as the flap load relief system was responding, as designed, to a turbulence-caused flap overspeed condition.