https://www.pcgamer.com/fortnite-search-between-a-bench-ice-cream-truck-and-helicopter-solution/

Week 4 of Fortnite's Season 4 Battle Pass challenges are here, and as usual, among them is another simple treasure hunt. This week you'll need to search between a bench, an ice cream truck, and a helicopter. As far as I know, there's no other helicopter on the island except for at Moisty Mire's new film studio. I did the dirty work and found it myself, so take a look at the map below and GIF above for a more precise indication of where to go. 

To make it easy, just find the helicopter and head north.