https://www.dailymail.co.uk/news/article-12985909/Wealthy-Zoom-executives-son-27-named-fourth-victim-Half-Moon-Bay-plane-crash-saw-homemade-aircraft-plunge-sea-girlfriends-body-one-recovered-fishing-boat-spotted-it.html
. . .
The fourth victim of a plane crash off Half Moon Bay, California,
has been identified as Isaac Zimmern, 27, the son of a wealthy
Zoom executive
Isaac and his longtime girlfriend, Emma Willmer-Shiles, were
among the four victims of the homemade plane crash that occurred
last Sunday
. . .
The plane was a "kit", sort of, called the "Cozy Mark IV",
a licensed derivative of Burt Rutan's "Long-EZ", made of
foam/fiberglass. The design/construction is very popular.
Young Zimmeren was an MIT grad in aeronautical engineering
and had been employed with several aircraft manufacturing
companies during his short career.
Note that there's an impression - maybe true or not - that
there may be some problem with this sort of aircraft
construction. John Denver died in a crash of one of these
sorts of planes ... it was billed as a suicide, but that
MIGHT not be true. I've heard that the fiberglas shell can
suffer from stress/UV degradation over time that might not
be obvious and that solvent/gasoline vapors might attack
the foam underframe causing weakening or "un-gluing" it
from the glass/epoxy shell.