According to three independent sources and the Aviation Herald, a specialist site that reports on the airline industry, data was passed on from EgyptAir Flight 804’s A320 Aircraft Communications Addressing and Reporting System (ACARS), indicating smoke was detected in one of the lavatories.
The smoke sensor went off at 2:26 am local time, followed by another smoke sensor going off 60 seconds later. This was then followed by a series of fault messages for the next 2 minutes, and at 2:29 am, the system abruptly stopped recording.
A US aviation expert, Bob Mann, said the data could point to rapid decompression or smoke and a progressive loss of flight control systems.
He indicated it could mean anything at this point – a bomb, or mechanical or electrical failure. The data recorder would be needed to know more about what happened onboard the aircraft right before it disappeared from the radar screen.
Mann also said as the wreckage is recovered, certain things will indicate if it was a bomb, such as the presence of shrapnel and blast residue as well as parts of the fuselage being bowed.
See Airbus A320 lavatory smoke detection test: