ALBUQUERQUE, N.M. — The pilots of a helium-filled balloon flying across the Pacific Ocean have surpassed a duration record as they approach North America after staying aloft for 138 hours and 27 minutes.

Pilots Troy Bradley of Albuquerque and Leonid Tiukhtyaev of Russia were headed south along the California coast Friday morning when they eclipsed the duration milestone of 137 hours, 5 minutes and 50 seconds aloft in a traditional gas balloon.

To establish a record, international aviation rules required Bradley and Tiukhtyaev to stay aloft 1 percent longer than the current record.

The duration milestone is considered the “holy grail” of ballooning. It was set in 1978 when Ben Abruzzo, Maxie Anderson and Larry Newman made the first trans-Atlantic balloon flight.

The pilots surpassed a distance record Thursday.