The small plane that crashed Dec. 30 off Molokai, killing three people, could have been hit by downdrafts, according to the National Transportation Safety Board.

“With dissipating rain shower activity directly above the accident site at the accident time, the accident aircraft was in a favored region for downdrafts,” an NTSB weather analysis said Monday.

The analysis said there was no lightning in the area at the time.

The board has issued no final report on the cause of the ocean crash. The occupants are presumed dead.

Neither the aircraft nor the bodies of John Mizuno, pilot Michael Childers and his girlfriend Whitney Thomas were recovered, despite a three-day search.

All three were from Oahu and in their 20s.

The single-engine Cessna 172M was returning from Molokai to Honolulu and had left Molokai Airport at 6:43 p.m. It disappeared from radar screens at about 6:49 p.m., according to the report.

The report said the airplane did a shallow climb to the northwest and began making a descending right turn at 2,525 feet. In less than 40 seconds it disappeared from the radar track about 1.5 nautical miles from the Molokai coast and 7 miles northwest of Molokai Airport.

“No emergency locator transmitter (ELT) signal was received during the search and rescue activities,” the report said. “Additionally, attempts to locate a signal from the pilot’s cell phone utilizing network-based location analysis were unsuccessful.”

The report said Childers had filed a visual flight rules plan and that conditions did not require instrument navigation.

Childers, 26, had rented the airplane, registered to Yumataka Kumiko and operated by Lani Lea Sky Tours LLC.

The airplane owner said the airplane’s most recent annual inspection was completed Dec. 28 and that the airplane frame had accumulated a little more than 10,131 flight hours.

The investigator indicated he did not know the total time the Textron Lycoming engine had been in operation, although it had undergone an overhaul.

The report said the pilot had done a preflight inspection of the airplane.

Childers and Thomas were servers at Haleiwa Joe’s, and Childers, who received his pilot’s license last year, had hoped to become a commercial pilot.