The controller knob labeling is incorrect. The results in selecting/commanding a cabin altitude which is too low, thus leading to the problem with the pressure differential. For example, if you plan to fly at rated ceiling of 25000 feet, procedure calls for setting 1000 feet higher, so you'd be setting the Carenado controller to a flight altitude of 26000 ft / cabin altitude around 6000 feet . . . .Problem is, cabin altitude of 6000 feet only equates to a flight altitude of about 20000 feet, not the 26000 it should be pressurized for.Once the correct altitude is selected, a possible secondary problem is the rate. If you climb at the spec rate (2000 - 2500 ft/min), that's going to be much faster than the default pressure change rate setting. Gotta dial the rate arrow until it's around 5 to 6 o'clock. (Cross-check the rate indicator dial and correct as needed to match your climb rate).In simulations, this is only a temporary problem since, as long as the controller is set correctly, the pressurization system will "catch up" and the light will go out. But, management will prevent the light's illuminating in the first place and will more closely match correct procedures.Same thing can occur during descent. This system does require management -- can't just be "set and forget." (However, you can set the initial altitude when still on the ground, since the pressurization [hypothetically] doesn't start until the wheels leave the ground.)The controller should look something like this based upon information in the aircraft manual:Name: controller.png Views: 326 Size: 55.3 KBSo, ignore the aircraft altitude on the controller and set the controller cabin altitude according to the following table. (1000 feet added to the flight altitude based on standard proceedure), which will result in a pressure differential just under 5.0 (1900D's cabin is rated for 5.1). Actual Altitude Cabin Altitude11000 60012000 135013000 200014000 275015000 340016000 410017000 480018000 530019000 610020000 670021000 725022000 800023000 860024000 925025000 9750