A Hawaiian Airlines flight from Sacramento to Maui was turned around over the Pacific Ocean Monday morning, landing in Oakland because of a mechanical issue, authorities said.

Hawaiian Flight 59, with 191 passengers and crew aboard, departed Sacramento International Airport at 10:05 a.m. PDT. After nearly an hour into the flight, it was diverted to Oakland International Airport, data from FlightAware showed. 

In a statement to CBS News Bay Area, a Hawaiian Airlines spokesperson said the flight was diverted to Oakland after developing an issue with the aircraft's backup cabin air conditioning unit; a backup AC unit is among the requirements for aircraft to fly more than three hours from the nearest airport. 

The pilot of the Airbus A321neo declared an emergency to obtain priority handling for the diversion, and the aircraft landed at OAK at 12:31 p.m. local time without incident, spokesperson Marissa Villegas said. 

Originally, the passengers were to be transferred to another aircraft to resume the trip to Maui, scheduled to depart at 2:25 p.m. However, Villegas said after securing the replacement aircraft, the flight crew timed out and were required to rest. The flight, renamed Flight 1059, is now scheduled to depart Oakland on Tuesday at 7 a.m. PDT.

"We are providing guests with meal vouchers and hotel accommodations, or the option to be rebooked on other flights," said Villegas. "Safety is our priority, and we apologize to our guests for this inconvenience.

The FlightAware data also showed Flight 59 had originally left the gate at SMF at 8:28 a.m., but did not take off for another hour and 37 minutes. 

"Our maintenance crews addressed and resolved a separate and unrelated issue prior to clearing the aircraft for departure from SMF," Villegas said.