The full report from the U.S. National Transportation Safety Board (NTSB) on the February 2024 helicopter crash that killed Herbert Wigwe, the former global chief executive officer of Access Holdings Plc, and his family members has been made public.

Abimbola Ogunbanjo, the former group chairman of Nigerian Exchange Group Plc, Wigwe, his wife Doreen, and their son Chizi were among the six individuals killed in the February 9, 2024, collision near the California-Nevada border.

According to the report, investigators determined the “probable cause of this accident to be: the pilot’s decision to continue the visual flight rules flight into instrument meteorological conditions, which resulted in the pilot’s spatial disorientation and loss of control.”

One of the contributing factors to the disaster, according to the NTSB report, was the helicopter company's "inadequate oversight of its safety management processes." Investigators found that the company failed to ensure pilots followed the necessary procedures prior to departure, documented maintenance issues, and completed flight risk analysis correctly.

“The pilot likely experienced spatial disorientation while maneuvering 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 investigation’s key discovery was that the helicopter's radar altimeter wasn’t working before the tragic flight. According to the investigation, the pilot had texted the maintenance director about a problem with this crucial instrument during a previous trip.

“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 report noted.

“The mechanic reported that the pilot and the DOM [director of maintenance] were aware that the radar altimeter was not functioning, yet they departed at 1822 on the positioning flight to pick up the passengers.”

Additionally, the investigation discovered that the pilot and flight following exchanged communications after arriving to pick up the charter passengers but "did not discuss the status of the radar altimeter or weather conditions."

Operating under visual flight rules in what eventually turned out to be instrument meteorological conditions, the N130CZ helicopter crashed, necessitating the use of alternative flight procedures and instrumentation.