The Magazine for Underwater Professionals

Nov/Dec 2017


Sonardyne technology used in hunt for flight recorder

Search for wreckage of crashed Irish Coast Guard helicopter supported by underwater locating equipment from Sonardyne International

Scout USBL system mobilised on a local fishing vessel searches the waters around Blackrock for the "black box" pinger signal, before deploying an ROV equipped with ROV-Homer to locate it

Earlier this year, a helicopter belonging to the Irish Coast Guard crashed into the Atlantic, tragically killing all four crew members.

Within hours of rescuers arriving at the scene of the accident off the west coast of Ireland, Sonardyne Scout ultra-short baseline and ROV-Homer acoustic tracking and relocation systems, owned and operated by Ireland’s Marine Institute, had detected emergency signals being transmitted from the aircraft’s flight data recorder (FDR). Using an ROV, search teams were subsequently able to pinpoint the exact location of the wreck which was lying in 40 metres of water.  

Rescue 116, a Sikorsky S92 search and rescue helicopter operated by CHC (Canadian Helicopter corporation) on behalf of the Irish Coast Guard, disappeared from radar screens in the vicinity of Blackrock, an isolated rocky islet. As part of the emergency response, Ireland’s Air Accident Investigation Unit (AAIU), together with the Irish Coast Guard, requested equipment and personnel from the Marine Institute to assist with the initial search for the wreckage. This included the Scout USBL system which was mobilised on a local fishing vessel and onsite within four hours of the Institute’s team arriving.

 The system is typically used for tracking divers, ROVs and underwater vehicles in waters up to 1000 metres, and is designed to be operated from virtually any type of vessel, small or large. Scout is portable, quick to setup and easy to use making it ideal for short underwater surveys and operations, according to Sonardyne.  


“Following a three-hour search, the Scout picked up the first faint signals from the aircraft’s 37.5-kilohertz Dukane (USA) underwater locator beacon attached to its flight data recorder,” explains a spokesman. “This was despite rough sea conditions and the vessel often operating within 50 metres of the rocky coastline.”


The Marine Institute deployed its work-class ROV and using the data from the Scout search, operators were able navigate the ROV to the wreck site. The ROV was also equipped with a Sonardyne ROV-Homer system which was used to ‘home’ directly in on the signals from the Dukane pinger. To make moving around through the debris field easier for the ROV’s pilot, a number of transponders compatible with the ROV-Homer were deployed to act as navigation waypoints.

Irish Navy divers later recovered the flight recorder which was found to be in good condition and transferred it to the UK for analysis.  

Reflecting on the performance of the Sonardyne equipment during the difficult mission, Aodhan Fitzgerald, research vessel manager for the Marine Institute, says: “The portable design of the Scout meant that we could rapidly mobilise the system onto a vessel of opportunity – a small fishing boat that was made available to us. Despite challenging sea conditions, Scout allowed us to rapidly locate the exact seabed location of the aircraft’s FDR whose recovery was crucial to solving the cause behind this tragedy.” 





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