- In December, a flight from Maui, Hawaii, came within 748 feet of plunging into the Pacific Ocean.
- On Thursday, The National Transportation Safety Board released a detailed report about the incident.
- An aviation expert told Insider that the aircraft's ground-proximity-warning system saved lives.
An aviation expert said passengers on a United Airlines flight from Maui, Hawaii, to San Francisco that plunged within 748 feet of the Pacific Ocean were saved by technology after a series of crew mishaps.
On Thursday, the National Transportation Safety Board released a final report on how United flight 1722 came within seconds of a major disaster on December 18.
The NTSB interviewed witnesses on the plane, including the captain and the copilot. The aircraft, which was flying in heavy rain and wind during takeoff, had its flaps set to the wrong angle because the copilot misheard the captain, according to the report.
But the plane's ground-proximity-warning system kicked in as the aircraft started rapidly descending toward the Pacific Ocean, giving the pilots time to react before it was too late.
"It alerted the pilots that they were getting near the ocean — it got the pilots out of a pretty close call," Anthony Brickhouse, a former investigator with the NTSB who is an associate professor in applied aviation sciences at Embry-Riddle Aeronautical University, told Insider. "They came within 748 feet from disaster."
As the system alerted the pilots, the copilot told the pilot to "pull up, pull up," which averted the crisis and allowed the plane to stabilize, according to the NTSB's report.
Investigators with the NTSB also said they were alerted about the safety incident two months after it occurred, but NTSB says the event did not require immediate notification because of the nature of the incident.
United Airlines did not immediately respond to a request for comment. The airline told Insider in February that the event was reported as the crew landed in San Francisco and that the pilots — who had a combined 25,000 hours of flight time — received additional training.
Passengers aboard the flight previously told CNN that the rapid descent felt like a "roller coaster" and that many people were saying final prayers during the sharp descent, which lasted 8 to 10 seconds.
Brickhouse told Insider that the lag in reporting the incident was another cause for concern. But he said other issues, like data retention, were tied to the slow reporting.
"The recorders had been written over by that point in time," Brickhouse told Insider.
"It's concerning as a safety professional and investigator that two months went by before the accident investigation board of the country found out about it," he added.
Brickhouse said the NTSB and the Federal Aviation Administration's push for more cockpit recording would be a safe step forward because technological reinforcements could help avert and investigate other flight disasters.
"Fortunately, overall, the technology worked, and ground-proximity-warning systems saved the day," Brickhouse told Insider.
