It is hard to overstate how difficult it is to hover a helicopter this precisely for this long. Helicopters are dynamically unstable. If you take your hands off the controls, they start to flip over almost immediately and become unrecoverable within 2-3 seconds.
The best analogy I've heard: imagine trying to stand on a basketball. Now imagine trying to stand on a basketball without flailing your arms around. Now imagine trying to do that for half an hour while someone's life depends on you not screwing up even for a single second.
The best analogy I've heard: imagine trying to stand on a basketball. Now imagine trying to stand on a basketball without flailing your arms around. Now imagine trying to do that for half an hour while someone's life depends on you not screwing up even for a single second.