The Barometric Pressure Sensor (or Altitude Lock) switch is located at the left side of the left joystick. It is turned off when the switch is rolled and locked upwards. This should disable the left joystick’s up-down motion being spring-loaded, giving it a loose feel. On the other hand, the Barometric Pressure Sensor is turned on when the switch is rolled downwards. This enables the left joystick’s up-down motion being spring-loaded so it will always return to the center.