A United Boeing 787-9, registration N27958 performing freight flight UA-2770 from Tokyo Narita (Japan) to San Francisco,CA (USA) with 4 crew, was climbing out of Tokyo's Narita Airport when the crew stopped the climb at FL290 due to a problem with the left hand leading edge flaps. The aircraft returned to Narita Airport for a safe landing at a higher than normal speed about 2 hours after departure.
The aircraft had attempted two flights the previous day, remained on the ground for about 21.5 hours, then departed for the occurrence flight, see also Incident: United B789 at Tokyo on Jul 2nd 2020, leading edge flaps trouble, Incident: United B789 at Tokyo on Jul 2nd 2020, leading edge flaps trouble.
The aircraft is still on the ground 10 hours after the second return to Narita.