One occupant of the plane carrying footballer Emiliano Sala and pilot David Ibbotson has been seen in the underwater wreckage.
A search on Sunday found the Piper Malibu plane on the seabed off Guernsey, almost two weeks after it went missing.
The Air Accident Investigation Branch (AAIB) confirmed the sighting on Monday morning.
It added it was now considering the next steps.
The “substantial amount of wreckage” of the plane, which went missing on 21 January, was found on Sunday morning after a privately-funded search was started.
The flight was carrying Argentine striker Sala and pilot David Ibbotson from Nantes, north west France, to Cardiff after Sala completed his £15m move to Cardiff City.