Kent Police are concerned about two 16-year-old girls last seen on 23 March at their homes in Northfleet in Kent.
Natalie Kelly and Rosina Lee are believed to be travelling to London to meet men they may have met on the internet.
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Captain Mike Green, a senior flying instructor, was piloting the two seater helicopter involved in the crash.
Saturday evening's weather for the east
Saturday evening's weather for the west