Passengers on a United Airlines flight experienced a horrifying dive when their plane plummeted out of the sky last year, falling to just 800 feet above the Pacific Ocean. 

The incident concerned United Airlines Flight 1722, a Boeing 777-200 that departed Maui, Hawaii, bound for San Fransisco on Dec. 18.

Radar data from flight tracking website Flightradar24 shows that the plane initially took off from Maui and climbed to 2,200 feet. At this point, the aircraft began “a steep dive that…reached a descent rate of nearly 8,600 feet per minute,” according to aviation news website The Air Current. 

The aircraft was able to quickly recover, it was reported, “but not before descending below 775 feet.” The plane was then able to climb to its cruising altitude of 33,000 feet and arrived in San Fransisco without incident. 

The climb out of the dive “produced forces of nearly 2.7 times the force of gravity on the aircraft and its occupants as that steep descent transitioned to an 8,600 foot per minute climb,” per The Air Current.

It remains unclear as to what caused the sudden drop. However, the plane had taken off in stormy weather, with the National Weather Service in Honolulu reporting showers and thunderstorms throughout the region. 

After landing in San Fransisco, the pilots filed “the appropriate safety report,” United told NBC News in a statement, adding that the airline coordinated with the Federal Aviation Administration and the Air Line Pilots Association “on an investigation that ultimately resulted in the pilots receiving additional training.”

“Safety remains our highest priority,” United said.

The airline said the flight’s two pilots had 25,000 hours of flying experience between them, and were fully cooperating with the FAA’s investigation.