I own a bonanza. There is no such thing as a pressure change that should do this.The door was simply not latched properly prior to takeoff, or there is a problem with the door latching mechanism.

(Written on 2015年07月31日)(Permalink)

This is exactly right. I have the "new" style of modern, digital transponder. It senses when my airspeed exceeds a certain threshold and only then does it turn on to ALT reporting. To meet this mandate, I'd need to manually override after every startup AND landing, or figure out how to reprogram this setting.

(Written on 2015年06月04日)(Permalink)