The Accident Investigation Bureau (AIB) has released the report of the accident involving Caverton Helicopter carrying the Vice President, Yemi Osinbajo, which crash-landed at Kabbah, Kogi State on February 2, 2019.
AIB said the preliminary report of the accident indicated that the cause of the crash was “brown out,” an in-flight visibility restriction caused by dust or sand in which the flight crew loses visual contact.
While issuing the report in its head office at the Murtala Muhammed International Airport (MMIA), Lagos, the Commissioner of AIB, Akin Olateru explained that brownout in helicopter operations is an in-flight visibility restriction caused by dust or sand.
According to him, the dust and sand could make the flight crew loses visual contact with nearby objects that provide the outside visual references necessary to control the helicopter near the ground.
The helicopter with registration number 5N-CML departed Murtala Muhammed International Airport, Lagos for Nnamdi Azikiwe International Airport Abuja, to conduct a chartered VIP flight from Abuja to Okene via Kabba and then return to Abuja, carrying the Vice President of Nigeria alongside eleven other people on board
The commissioner disclosed that although, the helicopter had a valid certificate of airworthiness, it hovered to land in a brownout condition.
According to Olateru, “During cruise at 5,000 feet and at about 10 minutes to touchdown, the crew noticed the flight recorder light on the Crew Alerting System (CAS) come on. Quick Reference Handbook items were accomplished. Another helicopter operated by Nigeria Police Force (Bell 412; 5N-PEJ) landed ahead of NGR002.
“The crew briefed on landing in brownout and used the company’s brownout landing procedures. During the landing, at about 50 feet to touchdown, a heavy brownout enveloped the helicopter and the crew lost visual contact with the ground.
“The Co-Pilot called out radio altimeter 35, 30, 25, 20, 15 and no more. At about 14:34 hours, the helicopter touched down hard on the right main landing gear and rolled over to the right.”
He noted that the crew carried out emergency landing procedures, which included immediate engines shutdown, fuel shut off, battery switch off, and generators switch off and all occupants of the helicopter were evacuated uninjured, adding that the helicopter was substantially damaged.
Olateru gave immediate safety recommendations, requesting that NCAA issues an advisory circular to all helicopter operators flying in Nigeria to be alert of the possibility and the effect of brownout and appropriate procedures be put in place to mitigate its effects.
“Caverton Helicopters Limited should ensure that flight operations are carried out in accordance with the company’s approved operations manual, vis-a-vis site survey and proper safety risk analysis are done before dispatching any helicopter to unapproved landing pads,” he added.