A guide to the maximum turbulence helicopter pilots should accept during an approach has been derived from research carried out for offshore oil support operations. It has been estimated, subject to operational validation, that vertical airflow velocity changes beyond 472ft/min (2.4m/s) pose unacceptable risks.
The research was funded by the UK Civil Aviation Authority Safety Regulation Group, and performed by BMT Fluid Mechanics with Qinetiq (Bedford) and Glasgow Caledonian University. The results came from a combination of windtunnel measurement and operational assessments derived from the ongoing Helicopter Operations Monitoring Programme.
The CAA says: "Turbulence around offshore platforms can represent a significant safety hazard and source of high cockpit workload.
"This was illustrated in the results of a questionnaire survey of offshore helicopter pilots...where turbulence around platforms was ranked as the greatest of the 15 factors contributing to workload and safety hazards that were considered."
Work on validating the turbulence criterion using data from Bristow Helicopters' HOMP is already under way, the CAA reports, adding that, when it is completed, "the turbulence criterion will be added to CAP 437 and incorporated in the Offshore Helideck Design Guidelines document [which] is endorsed by the Offshore Industry Advisory Committee's Helicopter Liaison Group".
The CAA says: "A useful spin-off from the validation exercise will be the addition of an offshore helideck turbulence mapping capability to HOMP. This will enable helicopter operators with HOMP to better establish operating restrictions, and to monitor the turbulence environment around offshore platforms on a continuous basis with minimal effort. With this facility in place, any unannounced modifications to platform topsides adversely affecting the airflow over and around the helideck should be rapidly detected and appropriate changes to operating restrictions made."
Source: Flight International