Pilot may have gone to front bathroom to place device which started smoke/fire. Comes back to cockpit and when alarms go off, sends other pilot to check it out. Locks cockpit and begins descent, screaming Alibaba Snackbar. Other pilot comes back and fight for control begins.
Egypt is going to lose a big source of income if pilot intentionally crashed plane so may try to cover up what really happened.
Doesn’t work with the ACARS reporting timeline - fire was first detected inside the bulkhead under/around the right front windows. Check the timeline (I’ve annotated it):
00:26Z 3044 ANTI ICE R WINDOW - right forward cockpit window anti-ice sensor has detected elevated temperatures when the computer wasn’t expecting to see them.
00:26Z 561200 R SLIDING WINDOW SENSOR - right side cockpit window sensor has detected elevated temperatures when the computer was not expecting to see them.
00:26Z 2600 SMOKE LAVATORY SMOKE - Smoke detected in the lavatory. The front lav on an A320 is one the *left* side of the aircraft. It shares the back wall of the cockpit on the left side.
00:27Z 2600 AVIONICS SMOKE - Smoke detected in the avionics bay which IIRC is under the floor of the cockpit.
00:28Z 561100 R FIXED WINDOW SENSOR - right side cockpit window sensor has detected elevated temperatures when the computer was not expecting to see them.
00:29Z 2200 AUTO FLT FCU 2 FAULT - Autopilot module 2 has failed, probably due to fire given prior messages.
00:29Z 2700 F/CTL SEC 3 FAULT - Part of main flight controls has failed, probably due to fire given prior messages.
This reads like an underfloor fire.
An Egyptair pilot had previously crashed a plane into the Atlantic. He was a Bill Clinton acolyte who had raped an hispanic hotel maid in New York, and the NYPD wanted to question him. Many of his colleagues had been warning about him for years. Raping a maid in Malaysia or Kinshasa may not be a big deal, but doing it in New York was a career ending event. A senior pilot lectured him about his behavior before he took off for Cairo from JFK. He could see the handwriting on the wall. He got his revenge on Egyptair by crashing into the Atlantic.