Egyptair 804 disappeared over the Mediterranean Sea last week. The aircraft, an Airbus A320, was carrying 56 passengers and 10 crew when it vanished from radar screens at about 2:30 am local time (00:30Z). There were no survivors.
While recovery of the wreckage is underway, the only other notable factor concerning the accident was a flurry of automated maintenance messages received from the aircraft shortly before its disappearance.
The system, known as Aircraft Communications Addressing and Reporting System (ACARS), is used to send data messages about the operational and mechanical status of an airliner to the company for various uses. For instance, when you bring up the arrival status of your flight on your phone, that exact arrival time is derived from data sent over ACARS. The system also sends maintenance status reports to help track the mechanical status of the aircraft and also to alert ground maintenance personnel of impending problems.
This system sent the following messages:
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
no further ACARS messages were received.
These messages indicate that smoke was detected by the lavatory and avionics smoke detectors and that the window heat computer detected an overheat condition. The avionics bay is an area below the cockpit where most of the aircraft's computers and radios are located. What these messages mean when taken together is anyone's guess. They could possibly indicate the presence of an onboard fire or might only indicate multiple erroneous inputs from a failure of the reporting system.
At this point no determination can be made about the nature of the malfunctions or their origins. This will no doubt have to wait until the data and voice recorders are recovered. This recovery effort is underway.