Smoke was detected in a bathroom near the cockpit of the doomed EgyptAir flight MS804 before it fell off radar, reports claim.
According to aviation industry website AVHerald.com, data transmissions from the Aircraft Communications Addressing and Reporting (ACARS) system suggest a fire on board the jet.
Messages in the final few minutes of the flight read:
- 00:26Z 3044 ANTI ICE R WINDOW
- 00:26Z 561200 R SLIDING WINDOW SENSOR
- 00:26Z 2600 SMOKE LAVATORY SMOKE
- 00:27Z 2600 AVIONICS SMOKE
- 00:28Z 561100 R FIXED WINDOW SENSOR
- 00:29Z 2200 AUTO FLT FCU 2 FAULT
- 00:29Z 2700 F/CTL SEC 3 FAULT
'FCU' refers to a unit in the cockpit which the pilot uses to input instructions into the flight computer, while 'SEC 3' is the computer which controls the spoilers and elevator computers.
NBC News, citing US intelligence sources, said officials have "no reason" to believe the messages are not accurate.
CNN said an Egyptian source had shown them a screengrab of the recordings.
Sixty-six people were on board the plane when it came down over the Mediterranean.
Work has begun on analysing data from the two black boxes from the fated EgyptAir flight that crashed into the sea in May.
French air accident investigators confirm the signal detected earlier is from a flight recorder.
The head of Egypt's forensics authority said it is 'too early' to know what caused the EgyptAir plane to crash into the Mediterranean sea.