Crashed Bristow Chopper Lost It Second Engine – AIB

The Accident Investigations Bureau (AIB) yesterday released findings made so far on the crashed Bristow helicopter killing six of the 12 people on board in Lagos on August 15.
The Commissioner and Chief Executive of the bureau, Dr. Felix Abali who briefed newsmen on the report yesterday said examinations suggested that the second engine of the aircraft suffered an ‘uncontained failure’.

He added that a component of the Sikorsky S-76 helicopter technically referred to as Pushrod Assembly which was supposed to be together pulled out from its position.

He said though investigation was still in progress to determine the actual cause of the crash, it was also discovered that the two crew members who died did not make any distress call before the crash.

“During the preliminary investigation, AIB discovered that the Forward Main Servo Input Control Pushrod Assembly had failed. The control pushrod tube separated from the control rod end with the bearing and the Jamnut. The Jamnut was loose and was not seating against the control rod”, he said.
Abali added that the aircraft had two life jackets which the pilots failed to deploy.
He said the voice data recorders (black boxes) of the helicopter were sent to the Air Accident Investigation branch in UK for data download, adding, 

“During the download it was discovered that the combined solid state voice/flight data recorder only contained information on the flight data while the separate cockpit voice recorder contained audio data. However, they were both successfully downloaded and are now being analyzed”.

“The rescue was promptly carried out by fishermen operating their boats around the crash site. The surviving passengers reported that the flight was normal until the helicopter suddenly spiralled, descended and impacted the waters of the underlying lagoon. Field examination suggested that No. 2 engine suffered an uncontained failure. The combined solid state voice/flight data recorder only contained information of the flight data. 

“The crew and passengers life vests were not activated. The crew did not declare an emergency, according to FDR data the upset lasted for 12 seconds”, he said.

Based on the fault discovered from the pushrod assembly, the AIB 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 advised the Nigerian Civil Aviation Authority (NCAA) to immediately carryout appropriate oversight actions 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 Federal Aviation Authority and Sikorsky Aircraft Corporation.