These two questions are geared towards the event of Virgin 747 gear up landing. Which one is to be marked as duplicate? The one asked later or the one with less attention?
In this particular case, I don't think they are exact duplicates, even if the questioners are thinking about the same incident. One question asks how to land "gear-up" - i.e. with no wheels down - and the other asks how to land with only the wheels on one side down. The technique in both cases would be somewhat different.
If you're asking about duplicates in general the consensus on meta.SE seems to be that the most useful question should be left open even if it's newer. It might take some time to identify the most useful one, of course.
If they are exactly same, the questions which is asked later is the duplicate.
According to time stamp, and the sequential identifier of the questions, this one came first:
- What's the technique for landing without one set of wheels?
This one is duplicate:
- Gear-up landing in a large airliner
However, sometimes there is some difference than the one which is asked earlier. In such case, it is best to reference the earlier asked question and mention that you want to ask something in addition to what had been asked.