California Plane Crash Brings Attention to Home-Built Aircraft

The one that went down was built over a period of nearly a decade by a retired dentist
By Newser Editors and Wire Services
Posted Jan 19, 2024 5:00 PM CST
California Plane Crash Brings Attention to Home-Built Aircraft
This June 22, 2022 photo provided by Thane Ostroth shows the Cozy Mark IV plane that crashed into the ocean off the California coast on Sunday, Jan. 14, 2024.   (Thane Ostroth via AP)

A small airplane that crashed into the ocean off the California coast on Sunday was constructed piece by piece over nearly a decade, one of tens of thousands of home-built aircraft that are part of a high-flying hobby taking off across the country, the AP reports. Federal investigators said they believe four people were aboard the single-engine Cozy Mark IV when it went down in the evening just south of San Francisco. No survivors were found and only one body had been recovered from the waters near Half Moon Bay and identified as of Thursday. There have been no official indications of what went wrong, but a witness reported hearing an engine losing power and cutting out.

Like commercial aircraft, all home-built planes are required by the FAA to be inspected annually for air worthiness. Cozy aircraft, a class of planes constructed by individuals rather than mass-produced by companies, 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." Thane Ostroth said he bought the plans for his Cozy, the one that crashed Sunday, for about $500 and started putting it together in a friend's basement in Michigan in 1999; by 2008, he was flying it. He sold it last year to an experienced pilot for around $100,000, which is about what he estimated went into the project over the decades.

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The plans come with a list of authorized suppliers of parts," said Ostroth. "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 said he heard about the crash in an online chat group for pilots and builders of Cozy aircraft. 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.

(More plane crash stories.)

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