Originally Posted by
Sir Korsky
It's very common in the US to pick up a IFR flight plan beginning at a point in space, if departing from a LZ without a instrument approach. Call the TRACON, get your clearance. They may ask you if you can maintain VFR to the first waypoint if the VFR transition is in controlled airspace and you may need to request special VFR. Picking up a pre-filed IFR flight plan in flight is also common, depending on how busy the sector controller is. I've always found ATC to be be extremely helpful and accommodating. How does this compare in the the UK?
In UK, helicopters operating from field sites seldom, if ever, "pick up a IFR flight plan". Most operate on an ad hoc basis, outside of controlled airspace, using lower airspace radar service where available (and there are significant gaps in the latter). There is no requirement to file an IFR flight plan when operating in Class G and no such thing as a clearance to operate within it. Most lower airspace in overland UK is Class G apart from airways, control areas, CTRs, and ATZs/MATZs. Basically, pilots manage their own departure and climb to MSA and pick up whatever en route ATC service they can glean. When requesting a radar service in Class G, controllers will generally advise that they can offer only a limited radar service.
In over fifteen years of corporate RW aviation, I've only ever filed one IFR flight plan prior to flight and that was almost fifteen years ago, simply because the captain decided to try it from a major airport to another minor one. In practice, we never got to fly any of the planned route and were messed about so badly we became concerned about our fuel state.