In chapter 19 of Hatchet, Brian opens up a survival pack that contains many useful items. One of the items is an emergency transmitter. Brian tries to turn it on, but as nothing seems to happen, he infers that it was broken in the crash and isn't working.
In the event, Brian's assumptions turn out to have been wrong—thankfully. The emergency transmitter really did work after all. A pilot, who turns out to be a fur buyer, of all things, heard the transmitter, swooped down, and came to land on the lake.
Brian is just about ready to eat the meal he's prepared from the dried-food packets he found in the survival pack when the pilot approaches him and tells him about the transmitter signal. The pilot had heard that people were looking for someone and immediately puts two and two together and realizes that they were looking for Brian.
Brian can't quite take in everything that's happening. In the event, he's so dumbfounded at his imminent rescue after spending so long alone in the wilderness,that he can only tell the pilot his name and ask him if he'd like to have something to eat. Brian's remarkable adventure is now at an end.