The Air Accidents Investigation Branch (AAIB) has started an underwater search for Cardiff City striker Emiliano Sala and his pilot David Ibbotson.
Sala and Ibbotson were travelling from Nantes - the Argentine's former club - to Cardiff on January 21 when the plane disappeared over the English Channel.
An official search for the two men was called off after three days as it was deemed unlikely that those on board survived.
However, the AAIB's Geo Ocean III vessel, along with a privately-funded vessel, started conducting sonar surveys in an area of sea off Guernsey on Sunday.
The search, which will last three days, comes in the wake of cushions believed to be from the plane being found on a beach on France's Cotentin Peninsula a week ago.
Friends, family and footballers from around the world helped raise £324,000 to fund the latest search.