A bit of cut and paste by the AAIB as they have given the same description to both incidents - helicopter rollover at Sherburn.
2 lucky pilots - presumably the R44 student has learned to secure items in the cockpit BEFORE starting up so it can be done properly and the 109 pilot has learned that 'gates' are there for a reason and if you don't make the gate then go around.
John R81 - Carbon Monoxide isn't CO2 but |I'm sure you know that
