Federal investigators said Thursday that miscommunication between pilots led to a United Airlines plane diving within 748 feet of the ocean’s surface shortly after takeoff from Hawaii in December.
The National Transportation Safety Board said in a final report that the crew failed to manage the plane’s path, airspeed and nose direction after the mix-up between the captain and co-pilot.
After a normal takeoff during heavy rain, the captain asked the co-pilot, or first officer, to reset the wing flaps, but the co-pilot heard “15” instead of “five,” according to the NTSB.
The Boeing 777 climbed above 2,200 feet (670 meters) after taking off from Kahului Airport on the island of Maui, then dropped more than 1,400 feet (427 meters) toward the Pacific Ocean. Both pilots told investigators they heard the plane’s ground proximity warning system call out “Pull up, pull up.”
The pilots were able to recover and resume climbing, then continued on to San Francisco without further incident, according to the report.
No one was injured in the Dec. 18 incident.
A United spokesman said both pilots received additional training and are still flying for the airline.
“There’s nothing more important than the safety of our crew and customers, which is why we’re drawing on the lessons learned from this flight to inform the training of all United pilots,” said the spokesman, Joshua Freed. “Our pilots voluntarily reported this event and United fully cooperated with the independent investigation” to improve safety for the entire industry.
The Federal Aviation Administration, which regulates airlines, said earlier this year that the United pilots reported the incident under a voluntary safety-reporting program. The FAA said it reviewed the incident “and took appropriate action.”
The incident attracted little attention until an aviation publication, The Air Current, reported on its analysis of data gathered from the plane.
The NTSB did not learn of the incident for two months, by which time information from the so-called black boxes had been recorded over.
The United flight took place on the same day that 36 people were hurt, 11 of them seriously, when a Hawaiian Airlines flight from Phoenix hit severe turbulence as it approached Honolulu. The National Weather Service had issued an advisory for thunderstorms and unstable air in the area.