National Transportation Safety Board (NTSB) investigators found that failures in the navigation system on a United Airlines flight from Lagos to Washington in January 2024 led to the autopilot disengaging on causing “altitude excursions”. On March 18, 2025, the NTSB released a preliminary report of its ongoing investigation into the incident that occurred on January 24, 2025.
During the incident, United Airlines flight 613, operated by a Boeing 787-8, experienced “altitude excursions” during cruise flight while transitioning over Cote d’Ivoire airspace at 36,000 feet.
The aircraft was operating a scheduled international passenger flight from Murtala Muhammed International Airport (LOS) in Lagos, Nigeria, to Washington Dulles International Airport (IAD).
There were 11 crew members and 234 passengers on board. One passenger suffered a serious injury, while 15 others had minor injuries. The aircraft also experienced some minor damage, NTSB officials added.
Approximately one hour and five minutes before the incident, inflight data indicated a failure in the left inertial reference unit (IRU). About 55 minutes later, a failure in the right IRU was reported, the NTSB report noted.
Flight data recorder information showed that at 00:30:57, the autopilot disconnected automatically, prompting the flight crew to take manual control, which triggered both the master caution and master warning alerts. At that time, altitude excursions began.
Three seconds later, the autothrottle disconnected. At 00:31:14, a stick shaker activation was recorded. 20 seconds after that, the autopilot was reengaged for one second, then disconnected automatically again. At 00:40:30, the aircraft started a right turn back toward Lagos. At 00:44:39, the autopilot was reengaged and remained engaged until the final approach to LOS Airport, the NTSB report continued.
The altitude excursions from 36,000 feet lasted approximately 12 minutes. During these fluctuations, meal service was taking place in the cabin, leading to some passenger injuries.
The flight crew decided to turn back and returned to LOS Airport, where the aircraft landed safely. Emergency responders met the airplane upon landing and transported injured people to a nearby clinic.
The NTSB said the investigation into the incident is ongoing.
