What typically happens to the main cabin door when it is opened from the inside?

When the main cabin door of an aircraft, such as the CRJ550, is opened from the inside, it typically swings outward. This design is common in many aircraft doors to ensure that the pressure differential between the cabin and the outside environment can facilitate the opening of the door safely when the aircraft is on the ground and not pressurized.

For the specific answer of the door "gradually falls downward," this scenario would not accurately reflect the functionality of aircraft doors as they are designed to operate in a manner that maintains safety and structural integrity during operation. The door is engineered to open outward smoothly when command is given, and will not simply fall or drop downwards, which could jeopardize passenger safety or cause damage. Instead, the door typically swings on its hinges, allowing for a controlled and secure opening process, guided by mechanics that ensure it operates as intended without uncontrolled movements.