The EgyptAir plane that crashed into the Mediterranean Sea on 19 May reportedly made three emergency landings the day before the tragedy.
The Airbus 320 was allegedly forced to turn around on at least three separate occasions in the 24-hours before the plane fell from the sky, killing all 66 people on board, according to a France 3 TV investigation.
The plane was said to have made six rotations between various airports before the crash and – on take-off from three different airports – irregularities were reported to ground staff by the flight's Aircraft Communications Addressing and Reporting System.
The cause of the irregularities are not explained but, at each instance, the plane was said to be given the go-ahead to continue its journey. Egyptian investigation sources have denied the claims being reported across the media.
Former aviation security official, Jean-Paul Troadec, told Euronews: "These new findings are an important element for the investigators. We cannot presume to know know exactly what happened on board but it's not entirely normal to turn around several times after a technical incident without finding anything."
Flight MS804 had been travelling from Paris to Cairo when it disappeared at around 2.45am Cairo time (1.45am BST), with many presuming a terror attack had downed the plane – although no group has taken responsibility for attack and no conclusions have been drawn as to the crash.
At the time of the crash, Airbus said that the aircraft – delivered to EgyptAir in 2003 – had logged 48,000 flight hours up to 19 May, AP reported.
There were 56 passengers on board the flight and 10 crew members, with the nationalities of those involved in the fatal crash identified at 30 Egyptians, 15 French nationals and 1 UK national.
Wreckage from the crash has been found thus far, including body parts and plane debris with French investigators confirming, on 1 June, that the black box from the aircraft had been detected following a search of the area.
EgyptAir was not available for comment.