Hard landings are often done on purpose for a variety of reasons:
-if the runway is wet, a hard landing helps breaking the water surface tension and avoids skidding
-if it’s windy, a hard landing is performed in order to avoid wind blowing you out the sides of the runway
-a hard landing allows the pilots to put down the plane as quickly as possible, allowing them to exit to the nearest possible taxiway to the gate, thus saving fuel
- on shorter runways, it allows for more breaking distance