A) it's big, but in a lake it varnishes easy.
B) lake isn't forest. In winter, it makes an obvious landing option when things go wrong.
C) chances are it crashed, not landed. Perhaps a fire weakened the ice, hot engines etc. If it landed one would expect radios to work.
D) it hasn't been found since (but others have), so I eould suggest it's "not easy to see".
The Yukon is big, and population is sparse, so its possibly on land, but speaking as a golfer, if there's water around, it's likely in it.