What do we know so far?
Aircraft was based in the northeast corner of Portugal at Marcedo de Cavaleiros, where I show only a hospital helipad. It undertook a medvac call from Braganca, about 30 miles further northeast near the Spanish border, and transported a patient to Porto. Presumably done in the afternoon. They then departed Porto presumably to reposition back 100nm in Marcedo. Sunset in Porto is 1808Z, or 1708 local time. There was a 1.5 hour delay looking for the crash, search was started at 20:15 local, so takeoff shortly after dark, in crap weather as Aser has kindly provided. They didn't make it five minutes from Porto, crashing about 10 miles away.
The ELT didn't work, statistically they only work 60% of the time, less in helicopters, so no surprise there. What about radar following or does Porto not have radar? What about flight following? Satellite tracking? Check-in every 30 min? What kind of operational control system would not realize an aircraft is missing for 1.5 hours? Surely they don't rely on an ELT known to be unreliable.
There is no instrument approach anywhere near Marcedo, the closest one is their point of departure, Porto. Rising ground and mountainous the further northeast you go - Marcedo is 1800', many spot altitudes over 4000' in that area. Rules out IFR. Weather should have ruled out night VFR, but we don't know what operational limitations Babcock works under. I take exception to Arcal76 and Crab's assertion that the pilots should know better. Well, yes, but a sophisticated competent management should have clearly laid out safe operating procedures. It is never up to the pilots to fly where and when they want in any Commercial operation.
Was a tower really hit in low level controlled flight or was the aircraft already descending for some other reason? If low-level night VFR was expected and sanctioned by management, was the aircraft equipped with EGPWS, did the pilots employ an appropriate CRM for that kind of flying or was CRM only considered for IFR? Even the IFR JeppFD shows lots of towers on their route.