”Landing is hard” (without an article) should be accepted. The Romanian meaning covers both the general and particular meanings, we always articulate it. Reported on 2019-01-10.
I don't think that makes sense/sounds right. Difficult and hard are accepted.
Apologies for length. Learning to land an aircraft (without damaging it) is perhaps the most difficult part of flying. In the sense of difficult it's also hard. A difficult landing, meaning one that is challenging, can also end up being a soft landing - if the pilot is skilled enough and maybe a little lucky. If you feel that the plane really went bump on touchdown, maybe even broke something, then that is indeed a hard landing, but as an ex glider pilot, private pilot and a native English speaker I'd call that a heavy landing. May not seem right to others, but I was familiar with this phrase before being exposed to the aviation community so don't think it's just jargon. The common usage is seen for example in this: Ryanair Extreme Heavy Landing - YouTube https://www.youtube.com/watch?v=NZDTviYUP5M I do note that commercial airline manufacturers have tried to designate hard and heavy landings as different in quite a logical way - hard being eg. >2G and heavy being an overweight aircraft - but that is not the idiomatic way that in my view the language is generally used.
Thanks for your expertise. For me, a hard landing is bumpy and a heavy landing is not a thing. "Landing is hard" makes it sound difficult; "the landing is hard" makes it sound bumpy (probably a former Navy pilot with carrier experience).