Attempts are being made to recover the body from the plane wreck that was carrying Cardiff City footballer Emiliano Sala and pilot David Ibbotson.
The body was seen in the Piper Malibu N264DB on Monday (Feb 4), two weeks after the plane vanished near Guernsey.
Relatives of Sala and Mr Ibbotson were consulted before recovery work began.
The Air Accidents Investigation Branch (AAIB) will first try and move the body to the surface, before attempting to bring the plane up.
Investigators have been studying the wreckage, which is at a depth of 63m (205ft) about 24 nautical miles north-west of Guernsey, using a remotely-controlled underwater vehicle.
If the operation is successful, the wreckage will be moved by boat to a UK port then to the AAIB’s base at Farnborough in Hampshire.
Investigators would then study the remains of the plane in further detail to try and establish why it crashed. An interim report is due to be published in just over two weeks.
The plane was carrying Cardiff City’s new striker Sala, 28, and Mr Ibbotson, from Crowle, Lincolnshire, to Cardiff on January 21 after the footballer returned to FC Nantes to say goodbye to his former teammates.
AAIB spokesman John Hotson said there was always a possibility the wreck would not be raised and a decision would be made on the advice of salvage experts.
He added: “We are attempting to recover the body. If we are successful, we will consider the feasibility of recovering the aircraft wreckage.
“Strong tidal conditions mean we can only use the remotely operated vehicle (ROV) for limited periods each day and this will mean that progress is slow.”
Shipwreck hunter David Mearns, who found the wreckage using sonar in his vessel Morven, previously said it was “imperative” to recover the plane.
He previously said: “There’s a much greater chance they [the Sala family] will get answers if [the plane is] recovered.”
He approached the Sala family offering to look for the wreck after a crowdfunding page to look for the plane raised £340,000 (371,000 euros).
The plane was found mostly intact, despite Mr Mearns expecting a “debris field”, and one body was visible in footage captured by a submersible.