But it's seemingly OK to basically do that at night when stooging around the boonies at 200' when not on any IMC procedure and you can't even see 200' ahead of you. I kinda have a bit of difficulty trying to rationalize that.
From the report.
On the night of the accident, R116 was tasked by MRCC Dublin to provide Top Cover for R118 and was using a ‘Rescue’ call sign; the IAA informed the Investigation that based on these two factors the flight was considered to be a SAR flight and, at the Commander’s discretion, could avail of the alleviations/exemptions contained in the National SAR Approval.
The CVR indicates that the Commander’s decision to go to Blacksod for fuel rather than Sligo was based on a concern to save thirty minutes flight time following R118 out, and also on the return journey; furthermore, the Commander received a report ‘conditions good at Blacksod’. The CVR indicates that the Commander later noted that reports from Blacksod indicated a cloud base as low as 300 ft and APP1 was used to bring the Helicopter down to 200 ft over open water before turning inbound to follow the APBSS route. This flight profile was in accordance with OMF which allows a minimum height of 200 ft with the helicopter’s collective axis coupled to RALT, and an absolute minimum of 50 ft helicopter hover with collective coupled to an AFCS SAR mode height hold.
However, OMF also requires visibility sufficient for the requirements of the task and to satisfy any OMB requirements for system modes being used. Although not a system mode requirement, OMB says ‘DVE is defined as visibility less than 4000 metres or no distinct natural horizon. Circuits shall be flown at 500 feet with reference to the RADALT with speed at least VY. Once established on the final approach track inside 2 nm at 500 feet, couple or remain coupled to RALT, HDG and IAS and beep down to 300 feet (or deck elevation plus 50 feet, whichever is the higher), to be level by around 1 nm to run.’
The Crew completed DVE Approach checks, indicating that they expected that they would be operating in DVE conditions. However, in descending to 200 ft, whilst it allowed the Crew to obtain COCISS conditions (clear of cloud, in sight of the surface), it eroded a safety barrier – height above the surface – without a definite improvement in terms of horizontal visibility. Furthermore, at 9 NM from Blacksod and 200 ft above sea level, operating just below the cloud base, at night, there were no external visual cues available (e.g. identifiable light sources or discernible features), to allow the Crew to assess horizontal/forward visibility.