It all started when Neil deGrasse Tyson said: "An airplane whose engine fails is a glider. A helicopter whose engine fails is a brick," years ago. Now that might be true to a certain extent, but apparently, Destin Sandlin from the SmarterEveryDay YouTube channel thought that it's not entirely correct, and with the help of a helicopter pilot, he wanted to prove Tyson wrong.
Destin took a flight around Widgeon Lake in British Columbia with Bradley Friesen, the helicopter pilot, and discussed if a helicopter could land safely when its engine was busted. Turns out, it could land with a physics trick called "autorotation" instead of falling down straight like a brick. Bradley Friesen made Destin meet Gerry Friesen, who happens to be his teacher with 16,000 hours of experience to show how a helicopter lands. So they did turn off the helicopter engine mid-flight and landed safely.
If a helicopter's engine fails, then it depends on the blades and the flow of air to keep moving, or in this case, to land safely, instead of the engine power. While the engine is on and the helicopter flies straight, the air flows downwards through the rotors. When the engine fails, the pilot adjusts the collective, in other words, the thrust lever, to change the pitch angle of the blades to be able to use the air coming from below so that it can glide to the ground in balance. As you might imagine, it's easier said than done; it takes different factors such as the pilot's techniques, the right amount of speed, and lots of practice.
As the pilot Gerry Friesen says, it "just becomes a feel thing" at some point to do an autorotation landing.
Destin didn't exactly say that Neil deGrasse Tyson was all wrong, he was right in theory; a helicopter can crash like a brick when the engine fails if the pilot decides to do nothing, which was, apparently, unlikely in this case.