They sometimes don't. A Malaysia Airlines A330 took off from Brisbane with the pitot tube covers still on, resulting in no working airspeed indication. Several

They sometimes don't. A Malaysia Airlines A330 took off from Brisbane with the pitot tube covers still on, resulting in no working airspeed indication. Several people missed the covers, despite ostensibly specifically checking for them. https://simpleflying.com/pitot-probe-covers-remain-in-place-malaysia-airlines-airbus-a330-300-takes-off/ https://simpleflying.com/pitot-probe-covers-remain-in-place-...