Qantas Airways Ltd. said one of its A380 aircraft had a brief dive above the Pacific Ocean because of turbulence from another superjumbo plane.

The two Qantas jets were about 20 nautical miles apart in distance and 1,000 feet apart in altitude when QF94, flying from Los Angeles to Melbourne, was affected earlier this week, the airline said in a statement Thursday.

Australian television and radio host Eddie McGuire, who was on the flight, said the plane "jumped up and down for about 10 seconds" and that "somebody described it as the feeling of going over the top of a rollercoaster."

"Unexpected turbulence is why we always recommend passengers keep their seat belt firmly fastened at all times just as pilots do in the flight deck," Qantas Fleet Safety Captain Debbie Slade said in the statement. "There are a lot of safeguards in place to reduce the likelihood of wake turbulence encounters, but it's hard to eliminate."

The Australian newspaper cited a passenger who described a 10-second "freefall nosedive" about two hours into the flight that left Los Angeles late on Sunday.

"The lady sitting next to me and I screamed and held hands and just waited," the newspaper cited passenger Janelle Wilson as saying. "It was terrifying."