The United States National Transportation Safety Board (NTSB) has attributed the February 2024 helicopter crash, which resulted in the deaths of former Access Holdings CEO Herbert Wigwe, his wife, son, and three others, to pilot error due to spatial disorientation.

Earlier, a preliminary report revealed that the helicopter, registered as N130CZ, crashed while operating under visual flight rules, but encountered instrument meteorological conditions, which required different flight protocols and equipment.

The NTSB’s final report, released on Wednesday, also criticized the helicopter company for its "insufficient oversight of its safety management processes."

The report states that investigators identified the "probable cause of this accident" as the pilot's decision to proceed with a visual flight rules flight into instrument meteorological conditions, leading to spatial disorientation and a loss of control.

The crash, which occurred near the California-Nevada border on February 9, 2024, resulted in the deaths of all six people on board, including Wigwe, his wife Doreen, their son Chizi, and Abimbola Ogunbanjo, the former group chairman of Nigerian Exchange Group Plc.

Additionally, US accident investigators revealed that the helicopter company failed to ensure that pilots properly completed flight risk analyses, recorded maintenance issues, and adhered to required regulations prior to departure.

The investigation revealed that the helicopter’s radar altimeter was non-functional before the fatal flight, a critical issue the pilot had raised during an earlier flight.

The report detailed that the pilot had texted the maintenance director about the problem with the instrument, and a company mechanic attempted to troubleshoot it. However, the mechanic was unable to fix the issue, and the radar altimeter remained non-functional.

“The pilot likely experienced spatial disorientation while manoeuvring the helicopter in IMC [instrument meteorological conditions], which led to his loss of helicopter control and the resulting collision with terrain,” the report stated.

The report further noted that despite being aware of the altimeter issue, both the pilot and the director of maintenance decided to proceed with the flight.

The report explained, “A company mechanic performed some troubleshooting on the radar altimeter; however, he was unable to rectify the issue, and the radar altimeter remained non-functional. The mechanic reported that the pilot and the DOM [director of maintenance] were aware that the radar altimeter was not functioning, yet they departed in 1822 on the positioning flight to pick up the passengers.”

Moreover, after arriving to collect the charter passengers, the pilot and flight follower exchanged messages but “did not discuss the status of the radar altimeter or weather conditions.”