text: An escape slide is required on all commercial ( passenger carrying ) aircraft where the door sill height is such that , in the event of an evacuation , passengers would be unable to `` step down '' from the door uninjured ( Federal Aviation Administration requires slides on all aircraft doors where the floor is 6 f or more above the ground ) .
simplified: An escape slide is required on all passenger-carrying aircraft if the door is too high for passengers to step down from the aircraft uninjured . Federal Aviation Administration requires slides on doors where the floor is 6 f or more above the ground .