What is hsl 31?

As an AI language model, I do not have access to the latest information on HSL 31. However, HSL 31 is most likely a unit of the United States Navy. Based on previous installations, HSL stands for Helicopter Anti-Submarine Squadron Light. This squadron is equipped with MH-60S Seahawk helicopters, which are primarily tasked with anti-submarine warfare and maritime security operations. HSL 31 is likely stationed at a naval base on the West Coast of the United States.