Radar for Wave Height Measurement
The EnRoute Wave Height Measurement Problem
In 2011 Canadian Transportation Safety Board (TSB) issued their investigation into a S-92A accident offshore Canada in 2009, in which 17 people died and one passenger, Robert Decker, survived. Additionally this accident was subject to a public inquiry. The Hon Robert Wells QC’s Offshore Helicopter Safety Inquiry (OSHSI) focused more on some of the survivability and wider safety issues.
In advance of Transport Canada rulemaking as recommended by TSB, Canadian industry voluntarily stopped flying to installations with wave heights measuring in excess of six meters (equivalent to the certified ditching capability of an S-92A with a five bag floatation system). This action was several years in advance of the UK Civil Aviation Authority (CAA), who announced their intent in their February 2014 CAP1145 report (‘Safety review of offshore public transport helicopter operations in support of the exploitation of oil and gas’).
Off Newfoundland, wave height is determined by wave-rider buoys off St Johns and close to the offshore installations. The wave height in between is not however measured.
Aerossurance has previously reported on challenges of wave height monitoring in the UK.
The HF Radar Research
As early as 1955 peaks in high frequency radio wave echoes had been identified as due to ocean waves. Studies in the 1970s showed that surface currents, surface winds and surface waves could be derived from radar data.
The Canada-Newfoundland and Labrador Offshore Petroleum Board (C-NLOPB), the local offshore industry regulator, contracted research organisation C-CORE, formerly the Centre for Cold Ocean Resource Engineering, to examine if HF radar could be used to determine en-route wave height, and give near real-time knowledge of the sea state all the way from St John’s to the offshore installations.
The C-NLOPB briefed the UK Helicopter Safety Research Management Committee (HSRMC) in May 2013 (view the 3.5Mb presentation here).
However, in March 2014 it was reported at a meeting of the local Helicopter Operations Safety Committee (HOSC) that:
The C-CORE HF Radar Technology Report was presented to Operators [i.e. oil companies] in November 2013; it was decided by Operators to pursue other technology at this time.
The alternatives were not articulated at that time. It however remained a controversial matter locally: CBC: Monitoring of waves needs to improve, offshore workers say.
Aerossurance is an Aberdeen based aviation consultancy. For expert advice on offshore helicopter design, operations, survivability and safety, contact us at email@example.com
Follow us on LinkedIn for our latest updates.