58-04-01 DOUGLAS: Applies to All DC3 Series Aircraft Which Have an "Airstair" Type Cabin Door Installation. \n\n\tCompliance required not later than July 1, 1958. \n\n\tThe DC-3 Series aircraft passenger entrance door has been altered by modifiers to hinge the door at the bottom and install steps on the inside of the door, which are used for entering or leaving the aircraft when the door is opened. Numerous instances have occurred wherein the door has opened in flight, or a passenger has inadvertently opened the door and, in some cases, with fatal or near fatal results. \n\n\tIn order to overcome this hazard, it is required that means be provided for safeguarding against inadvertent opening of such doors in flight. CAM 4b.356-2 and -4 outlines the FAA policies which should be followed in complying with this directive.