Originally Posted by WeeWinkyWilly
Timer device ex Cairo (in wheel-well IED) that gets it through Paris and after departure CDG, completes the circuit to the barometric device that then initiates on descent Cairo. Not rocket science at all - but diverts attention to a security problem at Charles de Gaulle airport (when it's really a Cairo-based initiative and perp).
Likely wasn't ex-Cairo before CDG, flightradar24 has SU-GCC visiting Tunis & Asmara in Eritrea on May 18 before flying the return from Paris to Cairo.......but your theory is therefore still very feasible.