The Accident Investigation Bureau (AIB) has traced the causes of four air mishaps between 2009 and 2015 to poor crew judgement, mechanical fault and weather-related problem.
The commissioner and chief executive officer of AIB, Mr. Akin Olateru stated this in Lagos while announcing the release of final reports on three serious aircraft incidents and one accident which occurred in 2009, 2013, 2014 and 2015.
The accident involved Gitto Construczioni Generali Nigeria Limited Bell 407 helicopter marked 5N-BIC which occurred at Uyo Airport International Airport on October 21, 2009, while the incidents involved aircraft belonging to Aero, June 5, 2015; the Nigerian College of Aviation Technology (NCAT) Zaria, May 21, 2013; and the International Aviation College (IAC) Ilorin, August 18, 2014.
The Aero incident involved a Boeing 737-500 aircraft marked 5N-BLE and it occurred at FL330 en route Kaduna Airport; the one involving NCAT-operated Socata TBM 850 aircraft marked 5N-BZA occurred near Kaduna Airport, while the one involving IAC-operated Diamond DA42 aircraft marked 5N-BNH, occurred at the Ilorin International Airport.
AIB traced the cause of the Bell 407 helicopter accident to improper maintenance of the oil system which led to oil starvation resulting in the failure of the No. 6, 7, and 8 bearings in the power turbine section of the engine, leading to power loss, improper identification by the pilot of the transmission chip light illumination during flight instead of the engine chip light.
The accident was also linked to the pilot’s decision to continue with the flight from Uyo to Port Harcourt International Airport without identifying the cause of the transmission chip detector indication.
The report attributed the Socata TBM 850 incident to the crew’s decision to depart the Nnamdi Azikiwe International Airport, Abuja NAIA with the knowledge of weather forecast, and failure to follow the guidance provided by the weather radar advisory to avoid the impending adverse weather.
The incident was also attributed to late recognition of the icing/hailstorm encountered by the pilot during the flight as well as failure of the pilot to adequately follow aircraft certification standards (procedures/limitations) for turbulent air, storms and icing conditions penetration.
On the Bell 407 helicopter accident, Olateru said: “The Pilot decided to make an air return but could not make it to the Helipad as there was a ‘bang’ from the engine and the aircraft dropped uncontrolled to the ground and crashed,” the report said.
“The investigation identified the following causal and contributory factors: improper maintenance of the oil system which led to oil starvation resulting in the failure of the No. 6, 7, and 8 bearings in the power turbine section of the engine, leading to power loss.
“Improper identification by the pilot of the transmission chip light illumination during flight instead of the engine chip light. And the decision of the pilot to continue with the flight from Uyo to Port Harcourt International Airport without identifying the cause of the transmission chip detector indication.”
Meanwhile, Olateru said AIB which was established in 2006 by the Civil Aviation Act and commenced operations in 2007 had published 117 safety recommendations.
“This year from the 10 published reports, 35 safety recommendations have been made. Our statutory obligation is to investigate air accidents and serious incidents: and by our safety recommendations, mitigate them in order to forestall reoccurrence,” he said.