AOPA Pilot Magazine - June 2011 - 89

A normal exhaust valve resembles an overcooked pizza (top left): orange in the center and
black around the edges. Uneven patterns (top right) show poor heat distribution. Green
shading (below left) indicates valve damage. In advanced cases, exhaust valves
can become warped (below right) and failure could be imminent.
engine inspections are limited because
image quality is relatively poor and the
things mechanics see require a great deal
of interpretation. Also, only the operator
can peer inside the engine, and not the
aircraft owner or maintenance manager.
Eichhorn was convinced there had to
be a better way several years ago when he
came upon an alternative during a visit
to his dentist, Barry Rudolph, a fellow GA
pilot. Rudolph used an oral endoscope
to examine Eichhorn’s molars, and the
patient asked whether it would be possible
to obtain a similar device for probing
engines. As it turned out, Rudolph had
an older endoscope that he wasn’t using
and loaned it to Eichhorn to take to his
hangar. Since then, fellow pilot and Baron
owner Peter Wu, an anesthesiologist,
made it possible for Eichhorn to obtain
a newer model that provides HD images.
New oral endoscopes are expensive,
with price tags topping $30,000. But
used equipment can be found on eBay
and elsewhere for a small fraction of that
cost. Also, tubular cameras on flexible
leads can be purchased online (www.
chinavasion.com) for less than $40, and
mechanics say they fit inside cylinders
and image quality is excellent.
“A great thing about medical technol-
ogy is that it changes fast, and hospitals
are willing to dump their old equipment
as soon as the new stuff comes out,” Eichhorn
said.
Eichhorn is finding myriad aviation
applications for these medical devices.
A recent safety bulletin on Baron and
Bonanza flap actuator mounting plates
is easily accomplished using an endoscope
that provides a far better view of
affected mounting plates and linkages
than mere lights and mirrors. And engine
camshafts can be examined by removing
a lifter and inserting the endoscope—an
alternative to the far greater effort and
expense of removing cylinders or taking
engines apart.
“The beauty of this technology is that
you can easily share what you see with
aircraft owners, and that allows people to
make more informed choices,” Eichhorn
said. “By documenting and saving the
images, you can also monitor changes
over time, and that makes it much easier
to spot trends and patterns.”
Although the use of medical technol-
ogy for engine inspections may seem
exotic, Eichhorn said it’s easy to envision
a time when miniature cameras on
lighted, flexible probes will become standard
equipment for aviation mechanics.
“Our inability to spot burned valves
before they fail has been a problem for
a long time. If these medical devices
can help us do a better job, why not use
them?”
E-mail the author at dave.hirschman@
aopa.org.
AOPA PILOT • 89 • JUNE 2011
http://www.chinavasion.com http://www.chinavasion.com http://www.PennYanAero.com http://www.PennYanAero.com
AOPA Pilot Magazine - June 2011

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