inside history on Instagram: "Before the plane departs the gate, flight attendants perform a final check of the doors. They "arm" the doors, which means preparing the emergency slides in case they're needed during an evacuation. After arming their own door, each attendant checks a fellow crew member's door to ensure it was done correctly-this safety step is known as a "crosscheck." Once all doors are armed and crosschecked, the lead flight attendant conducts an "all-call," contacting each crew m