THE National Transportation Safety Board (NTSB), has attributed the cause of Herbert Wigwe’s helicopter crash to “pilot disorientation” and deficiencies in safety protocols by the operating company.

It disclosed this in its final aviation investigation report published on Tuesday, May 6.

It revealed that the probable cause of the crash was the pilot’s decision to continue the flight under visual flight rules into instrument meteorological conditions (IMC).

“We determined the probable cause(s) 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,” NTSB stated.

The ICIR reported that the former group chief executive officer of Access Holdings Plc, Herbert Wigwe, along with his wife, son, and other crew members, died in an ill-fated helicopter crash on February 9, 2024.

An Airbus helicopter with registration number EC 130B4 crashed near Halloran Springs, California, killing Wigwe, three other passengers, and two pilots on board.

The helicopter was operated by Orbic Air, LLC, as a Title 14 Code of Federal Regulations (CFR) Part 135 on-demand flight.

It explained that contributing to the accident was the “company’s inadequate oversight of its safety management processes,” including ensuring the pilots were accurately completing and updating the flight risk analysis, logging maintenance discrepancies, and ensuring the helicopter met Part 135 regulations before departure.

NTSB is an independent agency charged by the US Congress to investigate every civil aviation accident and significant accidents in other modes of transportation across the United States of America.

Commenting further on its findings, the NTSB said that in the days preceding the helicopter accident last year, the helicopter had been undergoing routine maintenance that involved work on the radar altimeter, which was a required instrument for Part 135 flight operations.

“About 1727 on the day of the accident, the accident pilot and a company mechanic/pilot repositioned the helicopter from the maintenance facility to the company’s flight operations base, and during the flight, the accident pilot noted the radar altimeter was not functioning,” it said.

According to the investigative bureau, during the return flight, the pilot texted the director of maintenance (DOM) about the issue, and after arriving at the company’s flight operations base, the pilot discussed the issue with the company flight follower (who was also the company’s president).

“According to the flight follower, who also held operational control of the charter flight, during the discussions, he told the pilot that the flight could not depart if the radar altimeter was not functioning.

“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 investigators’ report partly read.

It asserted that the mechanic reported that the pilots and the DOM were aware that the radar altimeter was not functioning, yet they departed at 18:22 on the positioning flight to pick up the passengers.

NTSB findings further revealed that about two minutes before the accident, the helicopter’s airspeed and altitude increased, with a slight deviation to the south of the freeway.

“It is unclear if the pilot was attempting an inadvertent instrument meteorological conditions (IMC) recovery manoeuvre. The helicopter continued the right turn for about 10 seconds when the helicopter began a rapid descent into terrain while maintaining the right turn,” it also stated.

It noted that witnesses who were travelling in their vehicles reported observing a fireball to the south of the freeway, and that the witnesses reported that the weather conditions in the area were not good, as it was raining with a snow mix.

The report established that the search and rescue efforts at the time were difficult due to weather conditions that included low visibility, rain, snow, and high winds.

“The helicopter wreckage, which was highly fragmented and not survivable, was located about 1 hour and 40 minutes after the accident,” NTSB stated.

The report also included that post-accident examination of the airframe, engine, rotor blades, flight controls, rotor drive, main rotor, and fenestron components identified no evidence of pre-impact malfunction or failure that would have precluded normal operation.

The engine displayed rotational damage signatures and resolidified metal deposits consistent with powered operation at impact, the report said, stressing that all recovered instruments, avionics, and portable/personal electronic devices sustained damage that prevented data extraction.

The NTSB maintained that the helicopter wreckage was consistent with a high-energy, right-side-low attitude impact with terrain.

Although the two pilots, aged 25 and 22, with “commercial flight instructor certification”, were properly trained, the NTSB said the pilot might have been susceptible to the Coriolis illusion when maintaining a constant turn if he moved his head, for example, to look from inside the cockpit to outside the cockpit.

The report added that the helicopter began to accelerate as it descended, which could have resulted in a somatogenic (false climb) illusion that led the pilot to believe the helicopter was climbing.

“The pilot likely experienced spatial disorientation while manoeuvring the helicopter in IMC, which led to his loss of helicopter control and the resulting collision with terrain,” it added.