A United 777 made a scary plunge toward the ocean shortly after takeoff

(CNN) — A United Airlines 777 leaving Hawaii in December plunged toward the ocean for 21 seconds shortly after takeoff and came within 800 feet of sea level, flight tracking data show.

Neither United nor the FAA indicated anyone was injured on United Flight 1722 on December 18.

The plunge occurred a little over a minute after takeoff, the data show.

The plane lost more than half its altitude and came within 775 feet of sea level, according to the data from FlightRadar24. The plane gained speed as it dropped 1,425 feet from 2,200 feet before regaining its climb out of Kahului on the island of Maui.

The data suggest the remainder of the flight was uneventful.

United said it conducted an investigation with the FAA and the pilots union “that ultimately resulted in the pilots receiving additional training,” adding the investigation is ongoing.

The pilots have a combined 25,000 hours of flight time.

“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.

Although the weather at the exact time is unclear, the National Weather Service reported the day set a daily record for rainfall at Kahului.

The incident, which is coming to light only now, was first reported by the website Air Current.