The report of the AIB gives insight into what transpired before the Sikorsky helicopter crashed last August. It also recommends steps to be taken to avert a recurrence.
Almost two months after the Sikorsky S-76C+ helicopter operated by Bristow Helicopters Nigeria, crashed into the lagoon in the Oworonshoki area of Lagos State, the Accident Investigative Bureau, AIB has come up with its reports on the accident, which claimed six lives, including two crew members and four passengers while six others were seriously injured. The helicopter, which had oil workers on board had departed from an offshore oil rig (SEDCO Express) on August 12, and was headed to the Murtala Muhammed Airport before the accident happened. The report revealed that neither the crew nor the passengers had the opportunity to either inflate their respective life jackets or deploy the raft before the crash, which happened around 1:30 pm. It also stated that the crew did not make a MAY DAY distress call before the accident. The development could be attributed to the short time within which the accident took place. According to FDR data, the upset lasted for only 12 seconds.
But as the report stressed, the crash of the helicopter had nothing to do with the naivety of the pilots. It maintained that the flight crew were certified and qualified to conduct the flight “in accordance with applicable Nigerian Civil Aviation Regulations (Nig.CARs). The Captain and Co-pilot had 1077:45 and 570 hours on the aircraft type
respectively.” Again, it was not as a result of poor maintenance culture on the part of the operators, since the report also revealed that “the helicopter was maintained in accordance with approved maintenance schedule,” adding also that there were no records of any deferred defects in the tech log. As the report further noted, A-Check 50hrs was carried out on the 10th of August on the aircraft, just two days before the deadly flight.
Though the report maintained that there was prompt response from fishermen at the time of the crash, they could only save six passengers whom members of the National Emergency Management Agency, NEMA subsequently sent to Gbagada General Hospital and Afolabi Medical Centre for first aid before transferring them to St. Nicholas Hospital where they are said to be responding to treatment.
As the AIB report stressed, the cause of the crash is yet to be fully known, as investigations are still ongoing. But during the preliminary investigation, they discovered that the Forward Main Servo Input Control Pushrod Assembly had failed. The report maintained that the Control Pushrod tube separated from Control rod end with the bearing and the Jamnut. “The Jamnut was loose and was not seating against the Control Rod,” the report further revealed, adding that the National Transportation Safety Board, NTSB Laboratory preliminary metallurgical examination of the Forward Main Rotor Servo Input Control Pushrod revealed that the separation was a pre-impact condition.
The AIB report stated that field examination suggested that No. 2 engine suffered an uncontained failure. The result was the disaster that followed. “Preliminary flight recorder data indicated that at 1000ft and 120Kts, the helicopter experienced sudden pitch up, and left roll with varying attitude of yaw, roll and pitch for 12 seconds until it impacted water at about 1531hrs,” the report stressed.
Meanwhile, the two black boxes of the crashed helicopter sent to Air Accident Investigation Branch United Kingdom, UK for data download, have been successfully downloaded and are currently being analysed for more information.
In the meantime, the findings of the AIB have spurred interim safety actions being taken by the Federal Aviation Administration, FAA and Sikorsky to ensure safety. They have both issued Emergency Airworthiness Directives. For instance, on September 10, Sikorsky Aircraft Corporation issued Alert Service Bulletin, ASB 76-67-57 on all S-76 model helicopters equipped with Control Pushrod Assembly P/N 76400-0034-059 and 76400-00014-071. The aim, the report said, was “To perform a onetime inspection of installed Forward, Aft and Lateral Main Servo Input Control Pushrods and Jamnuts and Tail Servo Input Control Pushrods and Jamnuts for proper installation, condition and security followed by application of Slippage mark on all Main and Tail Servo Input Control Pushrod Jamnuts”. Four days later, the Federal Aviation Administration, FAA also issued Emergency Airworthiness Directives, EAD 2015-19-51 to owners and operators of Sikorsky Aircraft Corporation model S-76A, S-76B, S-76C and S-76D helicopters.
On its part, the AIB has also made some recommendations. It recommended that Sikorsky Aircraft Corporation “should consider a redesign of the affected control pushrod assembly by introducing additional wire locking safety features between the Jamnut and the Pushrod to enhance better security.” It also urged the Nigerian Civil Aviation Authority, NCAA to, as a matter of urgency, carry out appropriate oversight action on all the Sikorsky S-76 series helicopters flying in Nigeria to ensure the implementation of the Emergency Airworthiness Directives, EAD and Alert Service
Bulletin, ASB issued by FAA and Sikorsky Aircraft Corporation. They believe that enforcing such safety measures would help avert a recurrence.
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