BBC Radio 4 News have repeated (on the 10pm News) the account of a witness that the helicopter seemed to be 'looking for an alternative place to land' (this came from a transport company operating a depot close to the crash site) 'as there seemed to be something wrong (with the aircraft)'.
What about endurance?
To listen to the 6 o'clock News bulletin:-
http://www.bbc.co.uk/radio/noscript....o4/six_pm_news
From 10 minutes on, specific comment from 'witness' at 12 minutes to 12minutes 30secs.