In December, a United Airlines flight from Hawaii plunged to within 800 feet above sea level before leveling out and swiftly regaining its climb.
The San Francisco-bound 777, which departed from Kahului Airport on the island of Maui on December 18, rapidly ascended to 2,200 feet within about a minute of takeoff.
Rod Williams II, a passenger on the flight, told CNN that the plane started climbing at “a concerning rate.” Then, just over one minute after takeoff, the aircraft lost more than half its altitude, according to data from FlightRadar24.
The plane nosedived 1,425 feet in 21 seconds, at a rate of just under 8,600 feet per minute. That translates to about 97 MPH.
The plane then transitioned to a steep climb at about 8,600 feet per minute, creating a force nearly 2.7 times the force of gravity on the aircraft and its occupants, according to The Air Current. In all, the incident lasted no more than 45 seconds.
“It felt like you were climbing to the top of a roller coaster,” Williams said, according to CNN. “There were a number of screams on the plane. Everybody knew that something was out of the ordinary, or at least that this was not normal.”
For comparison, the Titan rollercoaster at Six Flags in Arlington drops 225 feet at 85 MPH.
“When the plane started to nosedive, multiple screams are being let out, at that point,” Williams told CNN. “It’s tense; you don’t really have a chance to speak or to conjure up words. You’re just kind of gripping the seat and praying under your breath.”
After an uneasy ten minutes following the incident, one of the pilots reassured the passengers that they were safe.
“Someone from the cockpit got on the intercom and said, ‘Alright, folks, you probably felt a couple G’s on that one, but everything’s gonna be OK. We’re gonna be alright,” Williams related, as per CNN. He added that the rest of the flight went smoothly. Ultimately, no one was injured on the flight.
Williams, who studied aviation, did not learn until eight weeks later that “we were about 5 to 5.2 seconds from hitting the water. … I’m definitely counting my blessings,” he told CNN.
The National Transportation Safety Board (NTSB) initially stated that it was not planning to investigate the incident but later reversed course and announced on Twitter that it would investigate. On Tuesday, the NTSB tweeted that “a preliminary report is expected in 2-3 weeks.”
The FAA investigated the flight but has not shared the results publicly, telling CNN that the “confidentiality of this program is critical to its success. The United Airlines flight crew reported the incident to the FAA as part of a voluntary safety reporting program. The agency reviewed the incident and took appropriate action,” the FAA told CNN.
United Airlines, the FAA, and the pilots union conducted a joint investigation which “ultimately resulted in the pilots receiving additional training,” United Airlines told CNN, adding that the investigation was continuing.
“Safety remains our highest priority,” United spokesman Josh Freed told PEOPLE.
On the day of the incident, the National Weather Service reported that Kahului received record rainfall, according to The Air Current. It is unclear if the weather was a factor in the frightening event.
The incident was just one of several close calls by major airliners in recent months. In January, an American Airlines flight crossed a runway at New York’s John F. Kennedy International airport while a Delta Air Lines flight was set to take off, The Washington Post reported.
This month, a FedEx cargo plane at Austin-Bergstrom International was just 100 feet from a Southwest Airlines flight after both flights were cleared to use the runway.
There has not been a major fatal crash on a U.S. airline since 2009, according to Reuters.