Dressed in a helmet, wetsuit and yellow fins, Molnar steps off the landing skids of a helicopter hovering 15 metres above Cape Banks on the northern headland of Botany Bay to demonstrate a lifesaving mission.

Attached to a cable, he spins as he descends to an exposed rock shelf close to the rusting remains of the SS Minmi, offering a thumbs up signal to fellow crewman Clay Allison.

Allison acts as the eyes and ears for Molnar and helicopter pilot Matt O'Brien, watching for any hazards that may imperil a rescue mission.

A former soldier and police officer, Molnar lands on the rocks, waits the   five to 10 seconds it may take to retrieve a person in distress, and then ascends back to the helicopter.

He repeats the winch training exercise as fishermen cast lines from the rocks below the cliffs at La Perouse. None are wearing lifejackets despite a new law making them compulsory along this stretch of coast.

It seems like another case of overreach by the nanny state until Molnar plays footage of a rescue mission he performed last year in the Royal National Park.

"You're happy with seeing someone face down in water?" he asks as the rugged coastline comes into view.

The view from the camera mounted on Molnar's helmet shows a picture-perfect day. But a powerful swell has swept a fisherman into the water and is dashing him against the rocks in front of his distressed friends.

"I didn't spot the [patient] at first for a while," Molnar says. "The wash makes it difficult to spot [him]."

Molnar is knocked over by waves, pushed onto rocks and has a fin ripped off before he is finally able to secure a harness around the unconscious 30-year-old man and signal to the air crewman to haul them up to the helicopter.

The crewmen, who later received bravery awards, resuscitated the man and handed him to paramedics who were able to get his heart beating again. But he later died as a result of brain injury following oxygen deprivation.

Molnar plays other footage of swimmers in conditions over their heads and even walkers who have taken a wrong turn and ended up stranded on a cliff.

One of the most dangerous spots for rock fishing is in front of the Sydney Westpac Life Saver Helicopter Base at Cape Banks.

A sign, which features a skull-and-crossbones and is translated into Korean, Vietnamese and Chinese, warns in uncompromising terms of the perils of rock fishing, with a changeable death tally that currently reads four.

Anglers who do not wear safety gear risk a $100 fine. New laws came into operation on December 1.

"Most of our rescues are right along here," O'Brien says, including a rock fisherman who was winched to safety at Yellow Rock in December. However, the rescuers were unable to find his friend, who was not wearing a lifejacket. His body resurfaced some days later.

Seventeen rock fishers have drowned in the Randwick Council area in recent years. Surf Life Saving NSW recorded 80 drownings from rock fishing between 2006 and 2016, second only to 125 swimming fatalities.

A 2015 NSW coronial inquest into the deaths of nine anglers was told each rock fishing fatality costs the community between $450,000 and $600,000.

There are two aerial surf rescue helicopters (known as Lifesaver21 and Lifesaver 23)  that operate along Sydney's coast and southern NSW. They perform an average of 600 rescues each year.

High winds and storms do not prevent a chopper rescue although heavy fog can cause difficulties. Sometimes a rescue crewman may be dropped in to stay with a patient if conditions become too dangerous for the aircraft.

Once a call is received, the response of the aerial surf rescue team is lightning-quick.

"If it's a water job, the [rescue swimmer] will go straight in and put his wet suit on," O'Brien says. "As that's happening, the crewman is wheeling the helicopter out. I'll finish up the phone call and follow the helicopter as it goes out. The rescue swimmer will come out, jump on board and we're gone in three to four minutes."

With a top speed of 100 knots (or around 185 km/h) and a tail wind, O'Brien, an emergency services pilot with more than two decades' experience, says he can fly to a rescue site in as little as 30 seconds.

Once there, the crew devises a rescue plan, which O'Brien says they must all agree: "There's a lot to go through before the decision to put your crewman in any danger."

Rescue methods include the "snatch and grab", which involves the chopper hovering directly over the patient while the rescue crewman descends and plucks them out of the water.

If access is impeded or a person is close to cliffs, the rescue swimmer is attached to the aircraft with a floating line that allows them to swim towards a patient.

On rare occasions, O'Brien says a patient will also be asked to jump into the water if a vessel is about to be smashed into rocks.

During the summer months, the aerial surf rescuers respond on average to two or three calls every day. O'Brien says the surf rescue helicopter is often busiest on days when the ocean is deceptively calm, rather than roiling with huge swells and big surf.

"It will be rock fishermen, surfers and sometimes the swells just get up and they're just not prepared for it," he says. "A rogue wave will come through, grab someone and pluck them into the water. And when you're fully clothed, that's when you're really going to struggle to swim."

In contrast, he says: "When you have these horrendous conditions most people tend to be smarter now and they don't go out."

However, the wild weather and huge waves that pummelled the NSW coast in June – eroding about 50 metres of Narrabeen and Collaroy beaches, and damaging the Coogee Surf Life Saving Club – created plenty of work for the aerial surf rescue.

In one day O'Brien piloted 13 rescues including surfers at Manly, kayakers at Bundeena and body boarders at Little Bay.

"We bounced from one rescue to the next and the next," he says. "It was one of the busiest days we've had in a long time.

"At Manly unfortunately there were people thinking 'What an opportunity to get the big wave'. I'm not one to say everyone out of the water. There are guys who can surf 60-foot [18-metre] waves."

Surprisingly, the rescuers are not always met with gratitude.

Patients may be embarrassed or worried about the cost of being plucked from the water even though the rescue service is a not-for-profit.

"And in the aircraft they're thinking, 'When's the credit card machine coming out?' That never happens," O'Brien says.

But rescues are not cheap. The two rescue choppers costs $4.8 million to operate, with annual grants of $1.1 million from the NSW government and Westpac, according to the fundraising and partnerships manager of Westpac Life Saver Helicopter Joanne Baxter. The remainder of its budget is raised by donations and fundraising.

"People are numb and a lot of times we drop them to a waiting paramedic," O'Brien says. "They disappear into the never-never and we fly back here.

"It's not until later that they realise how close they've come to getting dragged to the bottom of the ocean."