The pilots of the crashed helicopter that conveyed the Vice President, Prof. Yemi Osinbajo, on February 2, 2019, deployed an inappropriate landing technique that eventually led to the crash, the Accident Investigation Bureau stated on Tuesday.
The AIB also stated that the crew failed to adhere to company procedures, but was quick to state that its findings were not meant to blame defaulters, rather was to help improve on aviation safety.
The Chief Executive Officer of the bureau, Akin Olateru, disclosed this in Abuja during the release of four accident reports by the AIB.
The agency also warned airlines to stop tampering with the recordings contained in Cockpit Voice Recorder in the event of a crash or serious incident.
Olateru said any carrier found culpable of such act would be dealt with in accordance to the law.
On the aircraft that conveyed the vice president, the AIB boss said the Agusta Westland, AW139, helicopter with registration 5N-CML, was operated by Caverton Helicopters Limited.
He said the helicopter departed Lagos for Nnamdi Azikiwe International Airport in Abuja to conduct a VIP charter flight from Abuja to Okene via Kabba and return to Abuja before the crash later that afternoon.
Olateru said the positioning flight to Abuja was normal, as the helicopter was refuelled and the flight crew prepared for the VIP charter flight to Kabba.
The aircraft had 12 persons onboard including the vice president, his entourage and three crew members, (pilot, co-pilot and an engineer).
Olateru said the flight crew disclosed that they sighted the intended landing area as a result of the cloud of residual dust generated by the downwash of a police helicopter.
He noted that at about 50ft above ground level, a brownout set in as the helicopter tried to land.
He said the brownout condition led to the loss of external visual references, spatial disorientation and loss of situational awareness.
This, according to him, resulted in a misjudgment of distance and ground clearance, as the flight crew tried to control the helicopter’s movements for landing.
“The helicopter landed hard and rolled over on its right side,” Olateru.
On the contributory causal factor, he said, “Inappropriate landing technique used, non-adherence to company procedures for known or anticipated brownout condition during landing and lack of risk assessment.”
Others, as outlined by the bureau, included limited landing site preparation and planning prior to commencement of the flight.
The bureau further outlined some safety recommendations to the Nigerian Civil Aviation Authority and the management of Caverton Helicopters.
Olateru stated that before now the AIB under his management had released 27 final accident reports and that the additional four reports would bring the total final reports released from 2017 till date to 31.