Engine Parts

These parts (represented in-game and in the menu as a single metal gear) are scattered around the island, and can be located by using the metal detector (found in shelters at random). Three of them are needed to repair the helicopter.

The metal detector will periodically beep - the higher-pitched and faster these beeps are, the closer a part is.

The best way to find these parts is to get a vehicle that you can ride and equip a weapon. My personal favorite is the sled dogs since you don't have to go looking for fuel other then the fish you need to catch and feed to them which is easy--when you're on an island! So, hop on the sled dogs then switch to your metal dector and you can ride all over the map hunting for these engine parts in style. And, always carry some backup fish, don't want to be left stranded during a zombie apocalypse!! Happy hunting :D