The plane disappeared on its way from Nantes to Cardiff last month, prompting a two-week search.
A search of the wreckage began with a remote vehicle, confirming that at least one person has been found inside.
“Early in the search, the Morven identified an object of interest on the seabed using its side-scan sonar equipment,” a statement read. “It cleared the immediate area for the Geo Ocean III to use its underwater remotely operated vehicle (ROV) to survey the area of the seabed in which the object was located. Based on analysis of ROV video footage, the AAIB investigators on board the vessel concluded that the object is wreckage from the missing Piper Malibu aircraft, registration N264DB.
“The ROV carried out a further search of the area overnight, but did not identify any additional pieces of wreckage.
“Tragically, in video footage from the ROV, one occupant is visible amidst the wreckage. The AAIB is now considering the next steps, in consultation with the families of the pilot and passenger, and the police.
“The image shows the rear left side of the fuselage including part of the aircraft registration.
“We intend to publish an interim report within one month of the accident occurring.”
It was revealed last week that seat cushions from the plane had washed up on a beach in France