Zoom executive’s son, 27, is named fourth victim of Half Moon Bay plane crash that saw homemade aircraft plunge into the sea: His girlfriend’s body is only one recovered after fishing boat spotted it

The fourth victim of a plane crash off the shore of Half Moon Bay last Saturday, has been named as Isaac Zimmern, 27, – the son of a wealthy Zoom executive.

Zimmern was with his longtime girlfriend of more than 10 years, Emma Willmer-Shiles, known as Pearl, who was also 27. The childhood sweethearts were both living in nearby San Francisco. 

They were killed in the homemade plane being flown by Australian Lochie Ferrier, an experimental plane pilot who died alongside his venture capitalist fiancée, Cassidy Petit. Willmer-Shile’s body is the only one recovered so far and was spotted by a fishing trawler earlier this week.

Isaac was the son of Johann Zimmern, 59, who is head of Global Education Marketing at Zoom in San Francisco, and lives in a $1.1 million home in the Sunnyside area of the city.

Isaac Zimmern, 27, was with his longtime girlfriend of 10 years, Emma Willmer-Shiles, right, known as Pearl, who was also 27

Isaac Zimmern¿s body has not been found - but he was known to be onboard the light plane

Isaac Zimmern’s body has not been found – but he was known to be onboard the light plane

The couple are seen together in 2014

Emma Willmer-Shiles and Isaac Zimmern are seen at a May 2015 baseball game

The couple were childhood sweethearts and had been together with one another for more than a decade

Johann Zimmern, 59, is head of Global Education Marketing at Zoom based in San Francisco. His son, Isaac, was killed while riding in an experimental plane crash off the California coast

Johann Zimmern, 59, is head of Global Education Marketing at Zoom based in San Francisco. His son, Isaac, was killed while riding in an experimental plane crash off the California coast

Isaac's father, Johann Zimmern, 59, lives in a $1.1 million home in the Sunnyside area of the city

Isaac’s father, Johann Zimmern, 59, lives in a $1.1 million home in the Sunnyside area of the city

Rescuers with the San Mateo County Sheriff’s Office have continued to search for the other three occupants.

Ferrier was known in the ‘experimental aircraft’ community and had graduated from MIT in 2019 with aeronautical engineering degree.

He worked at Beta Technologies – an electric plane company.

He moved to California to work at Magpie Aviation in Hayward, which specializes in electric aircraft. 

Emma Willmer-Shiles, pictured. Her body was recovered while rescuers continued to search for the other three occupants of the experimental plane

Emma Willmer-Shiles, pictured. Her body was recovered while rescuers continued to search for the other three occupants of the experimental plane

Lochie Ferrier, Cassidy Petit (pictured, together) and Emma Willmer-Shiles were on Tuesday named as the victims of the smash in Half Moon Bay, near San Francisco, on Sunday

Lochie Ferrier, Cassidy Petit (pictured, together) and Emma Willmer-Shiles were on Tuesday named as the victims of the smash in Half Moon Bay, near San Francisco, on Sunday

Last October, Ferrier – from Armidale in New South Wales – announced his engagement to Cassidy Petit, a venture capitalist at RH Capital, specializing in reproductive and maternal health, with Ferrier proposing while on vacation in Baja California.

The pair shared a love of the great outdoors, with their social media full of scenes of climbing, surfing, snorkeling, hiking and skiing.

Her final post to Instagram, on January 1, was an engagement photo of the pair of them taken in front of the snow-capped mountains of Grand Teton National Park in Wyoming.

Horrifying footage showed parts of the wreckage of the Cozy Mark IV – a four-seat light aircraft that can be built from a kit – washing up on the rocks this week. 

Horrifying footage showed the parts of the wreckage of the Cozy Mark IV - a four-seat light aircraft that can be built from a kit - washed up on the rocks this week

Horrifying footage showed the parts of the wreckage of the Cozy Mark IV – a four-seat light aircraft that can be built from a kit – washed up on the rocks this week

The fourth person on board has not been named. The plane took off from Hayward and toured the bay on Sunday before landing at Half Moon Bay at 5:04pm. It was on the ground for two hours, and then took off again from Half Moon Bay, crashing shortly after

The fourth person on board has not been named. The plane took off from Hayward and toured the bay on Sunday before landing at Half Moon Bay at 5:04pm. It was on the ground for two hours, and then took off again from Half Moon Bay, crashing shortly after

The plane took off from Hayward and toured the bay on Sunday afternoon before landing at Half Moon Bay at 5:04pm.

It was on the ground for two hours before departing from Half Moon Bay and crashing shortly after.

Witnesses at the Moss Beach Distillery told NBC Bay Area they saw the plane flying ‘erratically’ before they lost sight of it.

There have been no official indications of what went wrong, but a witness reported hearing an engine losing power and cutting out. 

‘They heard the engine sputter, and they kept eyes on the plane until they lost sight of it, just over the horizon,’ said Sgt. Philip Hallworth of the San Mateo County Sheriff’s Office.

‘That prompted a search and rescue by the sheriff’s office and coast guard.’

Ferrier, known in the 'experimental aircraft' community, graduated from MIT in 2019 with aeronautical engineering degree and worked at Beta Technologies - an electric plane company

Ferrier, known in the ‘experimental aircraft’ community, graduated from MIT in 2019 with aeronautical engineering degree and worked at Beta Technologies – an electric plane company

He moved to California to work at Magpie Aviation in Hayward, which specializes in electric aircraft

He moved to California to work at Magpie Aviation in Hayward, which specializes in electric aircraft

The Cozy Mark IV plane that crashed into the ocean off the California coast last Sunday. The small airplane was constructed piecemeal over nearly a decade in a Michigan basement, garage and backyard, one of tens of thousands of home-built aircraft that are part of a high-flying hobby taking off across the U.S.

The Cozy Mark IV plane that crashed into the ocean off the California coast last Sunday. The small airplane was constructed piecemeal over nearly a decade in a Michigan basement, garage and backyard, one of tens of thousands of home-built aircraft that are part of a high-flying hobby taking off across the U.S.

The Coast Guard said a helicopter and boat crew looked in a 28-square mile area for nearly six hours on Monday, searching for victims before calling off the search around mid-morning.

Hours later, a woman’s body was spotted floating in the water by a fishing crew.

The unorthodox nature of the plane means that an investigation is more complicated.

The plane was registered to an Oakland-based company called Winged Wallabies, Inc., according to Federal Aviation Administration records. 

‘The aircraft itself doesn’t have any flight data or cockpit voice recorders, because it’s such a small, light aircraft,’ said Scott Miller, a pilot and San Jose State University lecturer.

He told KTVU: ‘If there was a mechanical failure of some type, the wreckage would certainly indicate that.

‘Kit planes are flown every day of the week. Sometimes tracking the history of these types of airplanes are a little more difficult.’

The NTSB said a preliminary report into the crash will be completed in two to three weeks.

A probable cause report will take between one and two years. The Federal Aviation Administration is also involved in the investigation.

Thane Ostroth, a retired dentist began building the aircraft in 1999 and flying it in 2008, said he sold the plane last year to a young, experienced and enthusiastic pilot from Australia for around $100,000. Thane is seen alongside his wife, Ellen

Thane Ostroth, a retired dentist began building the aircraft in 1999 and flying it in 2008, said he sold the plane last year to a young, experienced and enthusiastic pilot from Australia for around $100,000. Thane is seen alongside his wife, Ellen

Thane Ostroth, a retired dentist began building the aircraft in 1999 and flying it in 2008, said he sold the plane last year to a young, experienced and enthusiastic pilot from Australia for around $100,000.

The cost is about what he estimated went into the project over the decades.

Ostroth said the buyer, in his late 20s, knew a lot about planes. He landed the plane perfectly on his first test flight, which is not easy to do.

‘I told him, `That was well done,´’ Ostroth recalled. ‘He said, `Thank you. I’ll buy the plane.´’

Ostroth said he heard about the crash in an online chat group for pilots and builders of Cozy aircraft, a class of planes constructed by individuals rather than mass-produced by companies.

He said it was ‘traumatic’ to know the plane he had spent so much time on had crashed with people on board.

‘It´s just a horrible feeling,’ Ostroth said.

Like commercial aircraft, all home-built planes are required by the FAA to be inspected annually for air worthiness. 

Cozy aircraft have the same safety record as commercially built planes of similar size, said aeronautical engineer Marc Zeitlin, who consults with the National Transportation Safety Board on crash investigations involving Cozy aircraft, including this one.

More than 33,000 amateur-built aircraft are licensed by the FAA, a figure that has tripled since the 1980s.

The administration designates any non-commercial, recreational aircraft as ‘experimental.’ 

Those can include planes built from kits with some prefabricated parts or from plans in which the builder buys or manufactures and assembles all the parts.

The four-seat Mark IV, at just over 16 feet long with a 28-foot wingspan, is a popular plane among the growing number of aviation hobbyists who build their own aircraft.

 Zeitlin owns one himself that he takes on day trips and cross-country voyages.

‘The misconception is that these are put together by baling wire and glue,’ said Zeitlin, CEO of California-based Burnside Aerospace. ‘But they are built using aircraft methodology.’

The Mark IV has a ‘canard’ design, with a small forewing placed to the front of the main wing, making it reminiscent of a duck stretched out in flight. It is lightweight, only about 1,050 pounds  empty, with the parts fitted together with epoxy.

With a top speed approaching 200 mph, it is fast, stable and fuel-efficient, Zeitlin said.

‘Like a sports car in the sky,’ he said. ‘Very fun to fly.’

Ostroth said he bought the plans for his Cozy for about $500 and started putting it together in a friend’s basement in Michigan. 

Eventually they moved construction to the home’s garage and then built a barn in the backyard for the final steps.

‘The plans come with a list of authorized suppliers of parts,’ said Ostroth, who now lives in Florida. ‘You buy foam, you buy fiberglass, you buy metal parts from all the manufacturers. And you slowly piece it together.’

Help can be found from other enthusiasts who post tips and advice in online forums.

Ostroth flew the aircraft regularly for 15 years. He called it ‘a wonderful little plane.’

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