What effect does closing the outflow valve have during cabin rate of climb?

When the outflow valve is closed, it indeed assists in slowing down a too rapid cabin rate of climb. The outflow valve regulates the escape of cabin air to maintain the desired pressure within the cabin. Closing the valve restricts the outflow of air, which in turn can help manage the cabin altitude and prevent it from climbing too rapidly due to potential issues such as sudden changes in atmospheric pressure outside the aircraft.

This action is particularly important in maintaining passenger comfort and safety, as excessive cabin climb rates can lead to physiological effects on the passengers and crew. Therefore, utilizing the outflow valve to control the cabin rate of climb is a key aspect of flight management in ensuring a stable and safe environment for those on board.