This is one reason why aircraft discovered many years after disappearing can seem almost impossible.
The airplane may have been there all along.
The searchers simply did not know where to look.
## A Mountain Can Hide an Airplane
Mountainous terrain presents one of the greatest challenges for aircraft searches.
An aircraft flying at high altitude can cover a huge distance in only a few minutes. If something goes wrong, the eventual crash location may be far from where investigators initially expect it.
Once an aircraft enters a mountain valley, radar coverage can become limited.
A wreck may also be located on the opposite side of a ridge from the last known position.
From the ground, searchers might pass within a relatively short distance without realizing that wreckage is nearby.
From the air, the situation can be equally difficult.
Metal debris can blend into rocky terrain.
Snow can cover an aircraft completely.
