Just a question (I usually have several, and would hate to now let anyone down).
With the newer cockpit doors on our twin-turbofan so-called "city-hopper" models, we have NO light or beeper in the cockpit to indicate whether the door is locked or not. We push and pull them after the lead FA closes it. There have been more than a few such planes which have taken off and the door has swung open. It was quite interesting when it happened with an Air Marshal sitting towards the front. You should see the numerous pages in our COM Supplemental section which attempts to explain these doors and the various combinations of functions. Many pilots' understanding of this info is not very clear.
Do some aircraft have indications which tell the crew that the door is locked or not quite locked?