"Perry J. Mick" wrote:

My last post was speculation about Tifft's piloting.  This
one is about his engine failure.

I hate to keep bringing this up, but I think we can learn
from accidents.  When you read this:

http://www.ntsb.gov/ntsb/brief2.asp?ev_id=20001207X03044&ntsbno=SEA95LA053&a
key=1

It is obvious the NTSB never determined a cause for his
engine failure.  They don't mention frozen pistons as Bill
did.

Here is a quote:

"Before removing the spark plugs, the propeller was found
to rotate easily. The top spark plugs were removed and all
four cylinders were checked for compression and suction.
Accessory gear and valve train continuity was established.
All of the spark plugs were removed and operating signatures
appeared normal. Clean oil was found in the engine."

This seems to say there was no fault in the engine.

They mention he had dual electronic ignition.  Could he have
had an electrical system failure?  Now this is something that
would bring my beloved rotary engine to a stop.  Maybe he
didn't build in enough redundancy into his electrical system
to be totaly dependent upon it for ignition?  More speculation,
sorry.

--
Perry Mick
Duckt N7XR
http://www.ductedfan.com

The pistons could also have cooled off and shrunk allowing the engine
to appear normal.

Paul Lamar

I heard from people that were close to them that the pistons had
been fitted tightly, tighter than stock.  The conclusion of the
people that knew the details was that the pistons seized and then
cooled off.   This was just a discussion with a few of Bruce's
close friends that knew about the motor and were trying to understand
what happened.  Couldn't be absolutely proven, so not in NTSB
report.  No slam on Bruce or his piloting, nobody can land an
EZ in the trees & mountains.  He possibly made a mistake in
the selection of non-std pistons, and (IIRC) had not test flown the
engine extensively, I think only one or two prior flights.  This is
all from memory, so may be in error. Please correct me if I have
made an error. I knew Bruce, but not real well.

Perry is thinking about what might have caused this tragedy and
applying this to understand any similar failure modes that could
affect his engine.  This is a GOOD thing, learning and improving
from these hard-earned lessons.  I think all critical systems that
can reasonably be redundant, should be.  Tracy's fuel injection
design is a good example.  It is impossible to make everything
redundant, but some things can be and should be.  Historically,
ignition systems were a prime failure item and were therefore
made redundant.  Careful thought to providing for
redundancies (when reasonable) will increase our safety and let
us all enjoy this sport more.  The multi engined aircraft carries
redundancy to new heights, but at high costs to buy and operate,
plus some very light twins actually won't fly on one engine, so you
have twice the chance of a failure, and no real flyaway redundancy
at the most critical condition.

Let's resolve to test fly our unproven systems near the airport until
we develop confidence that they are fully stabilized thermally and
do work properly.  Ya'll be careful out there.

Bill
Long EZ builder & pilot
BSME, MSME
EAA Technical Counselor

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