An air-traffic controller didn't notice the two Boeing 757s were on a potential head-on collision course, but one of the pilots made an emergency dive to avoid a U.S. Airways jet over the ocean near Hawaii last month, USA Today reported.
"We've got an emergency descent going!" the United Airlines pilot radioed to the Honolulu control tower.
The plane then dropped 600 feet in 60 seconds.
"It was a really violent, scary experience," United passenger Kevin Townsend, of San Francisco, told CBS News. "It felt kind of like the plane had gone dead in the air and started dropping."
The planes' onboard warning systems alerted both pilots that they were too close, noted the Federal Aviation Administration, which is investigating the April 25 event. The jetliners were traveling at 33,000 feet about 200 miles northeast of Kona, on the Big Island, about 11:15 p.m.
United Flight 1205 had just taken off from Kona for Los Angeles when the pilot dove to avoid the U.S. Airways Flight 432 from Phoenix bound for Kona.
At their closest point the two jets were separated by 5.3 miles laterally and 800 feet vertically, the Honolulu Star-Advertiser reported, citing preliminary radar data. CBS News said they came with 2.2 miles of each other.
An when aircraft is traveling at about 600 mph, those distances are too close for comfort, one expert said.
"Sixty miles an hour is one mile a minute," Peter Forman, a retired pilot and aviation expert, told Hawaii News Now. "Six hundred miles an hour is 10 miles a minute closure rate,"
This story has been updated.
(H/T: Drudge Report)