Accident Investigation Bureau (AIB) has linked the recent presidential helicopter crash in Kogi State to hazy weather condition that could have been averted by safety and risk assessment.
The bureau, in a preliminary report released in Lagos yesterday, observed that Caverton Helicopters Limited, operators of the aircraft, did not conduct site survey, safety and risk assessment of the landing field prior to dispatch of the flight.
It has, however, recommended the issuance of advisory circular by the Nigerian Civil Aviation Authority (NCAA) to all helicopter operators in Nigeria to be alert to the possibility and effect of brownout or haze.
Also, Caverton should ensure that flight operations are carried out in accordance with the company’s approved operations manual, vis-à-vis site survey, and that proper safety risk analysis was done before dispatching any helicopter to unapproved landing pads.
A 15-seater AgustaWestland (AW) 139 helicopter, managed by Caverton, crash-landed at the Kabba stadium ground while conveying the vice president and his team to Kogi State a fortnight ago when it. While the chopper, with registration number 5N-CML, was substantially damaged, all 12 occupants escaped unhurt.
Chief executive officer of AIB, Akin Olateru, said though investigations were still ongoing, preliminary findings showed that the helicopter hovered to land in a brownout condition. He added that about 50ft to touchdown, a heavy brownout enveloped the helicopter and the crew lost visual contact with the ground.
Brownout in helicopter operations is an in-flight visibility restriction caused by dust or sand in which the flight crew loses visual contact with nearby objects that provide the outside visual references necessary to control the helicopter near the ground.
The crew, during the post-accident interview, stated that they sighted the stadium as a result of the brown dust generated by the downwash of the police helicopter main rotor (the advance party of the vice president). The crew further stated that the approach was normal.
“After identifying the stadium, both flight crew members agreed on the selected landing spot within the stadium. The aircraft got into hover to land and at 50ft above ground level, a brownout set in.
“The crew lost visual contact with the ground and elected to use the Instantaneous Vertical Speed Indicator (IVSI) and Radio Altimeter (RAD ALT) to control the descent. The co-pilot began RAD ALT Callouts “35, 30, 25, 20 and 15,” the report read in part.