After having looked at dozens of Cruisairs, I can say that the door originally had a top latch that turned into the slip stream when closed, and an inside knob the turned the same part on the inside. The bottom latch has been a common addition, but not original. Having an inside latch that cant be released from the outside could be a big safety factor in the event of a hard landing or crash that the inside passengers are not able to help with opening. The sharks(insurance lawyers) would have a field day with that. ____)Gary, I will PM you. ____Grant.