As mentioned in the notes, it seems to happen due to the damage model. Landing often and slightly harder than usual drains your health. Even if there is only light damage to the inst, you pilot has drained health.
Landing and damaging inst, should not drain your health. You either die or you live. Unless you had a crash landing and managed to land but quite hard, than it is reasonable to have damage to pilot and crew.
Happens in any chopper after a few landings. 5-10 landings.