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Al,
I agree with you to a certain extent, but these “fixes” can
become worse than the problem. Look at Toyota. That system is so complicated
that even the guys who designed and built it don’t understand what the
failure mode is. Airplanes require more training to fly safely than cars
do and for damn good reason. If you are in the pattern and decide to try
a power off landing and inadvertently pull the mixture instead of the throttle,
what have the certified manufacturers done to prevent the engine from
stopping? In order to install a proper fix, you have to consider every
possible scenario. That is just not possible. The original reason
for the cold start switch (I think) was to act as a choke to richen the mixture
on starting. Then because it was there, it is used in the programming
process. Now most folks seem to use the store button to give primer
shots, but the cold start switch can not be easily removed because it is used
in programming. I think a switch guard would help, but nothing can be
made foolproof because fools are so damn ingenious.
I don’t think that every time someone makes a boo boo in the
cockpit, the suppliers should run off and design some “fix”. This
is different if the problem is internal to the device whereby it doesn’t perform
as expected under some standard circumstance. Like Toyota for instance.
Bill B
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Al Wick
Sent: Monday, March 15, 2010 10:09
AM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: Ut-Oh...
Another dead stick landing. Same old causes. Fortunately
no fatalities....this time.
Let's pretend you are the copilot. You've been flying along
for 10 minutes. When the pilot says: "Hey Bob, how about giving me 150
times as much fuel right now." You'd say:"WHAT?!! You are
crazy, that will shut down the engine!"
Pilot:" Oops, my bad. O2 and egt's are normal. My
mistake"
Does that sound far fetched? Nope. It happens a couple times
a year. Often it's a case where the pilot inadvertently drives the ecu
to super lean condition. Engines suddenly quits. Let's use your home pc as
an example. You tell the pc to delete all files on your hard drive. It
recognizes this is most unusual and could be catastrophic. So it says:"Are
you sure you want to wipe out hard drive? This could be fatal"
Every failure has more than one cause. Yes, the pilot
inadvertently flipped the "cold start" switch when he was reaching
for his gps. Was it Ed last year who inadvertently rotated the mixture to full
lean? Last year Keith's passenger bumped the ecu mixture knob while
getting in the plane. So, yes, Ed, Keith, and Dave all made the same
mistakes. They placed a switch capable of shutting down the engine in the wrong
area of the instrument panel. End of story? NO!
As soon as one of these ECU suppliers adds the "Are you
sure?" logic, then all of these failures disappear. Pretty simple logic
statement. Actually, there are a whole bunch of ways this can be handled. I had
to do this type of programming with industrial plc's because these same
"oops" were so common. Think about this. If engine has been running
for more than 5 minutes, only allow small mixture changes. Never enough to shut
down engine. So let's say that 100 will shut down engine, then we only allow a
change of 20 each minute.
I think the ECU providers recognize builder error.
"Whew! Not MY problem." They don't ask: "Is there
something I can do to save lives?" If they make these simple
changes, then every single plane is no longer sensitive to these common
"oops" scenarios. So yes, if Dave moves his switch, HE will be
safer. But if the ECU supplier makes this simple programming change, then every
single plane will be safer. Real world mistakes will no longer shut down the
engine.
I want these suppliers to be successful. I want fewer plane
crashes. But it's not going to happen unless you guys (privately) encourage
these simple changes.
This group is making good progress on failure reduction.
There are a handful of ecu changes that will really make a difference. Please
pursue! Question question question.
----- Original Message -----
Sent: Sunday, March 14,
2010 7:10 AM
Subject: [FlyRotary] Re:
Ut-Oh...
I know Dave or Jon
wouldn't phrase it this way but I've already received a number of messages from
others about these two recent in-flight power failures due to EC2 issues.
Jon's was due to a loose mounting nut inside the EC2 that shorted the
main power input filter to ground and burned open both foils from the 2 power
input pins. How lucky was that.
Anyway, at the risk of sounding defensive, I thought I'd share my response
to one of them that suggested changing the EC2 case to an external mount of
some sort. I'm sure there are scores of messages on the way urging me to
place switch guards on the cold start switch : )
REPLY
Hello ----------
I'm aware of the failure and have the unit here for repair.
Like a thousand other critical details in building an aircraft, it
is not possible to explicitly spell out all of them. The precise method
and hardware used to accomplish it are not part of the EC2 or the instructions.
The first paragraph of the installation guide does say the following:
"Needless to say, the quality of installation is just as important as the
quality of the hardware itself. It is not practical to include a course
on proper electrical wiring practices in these installation instructions, but
it is imperative that proper wiring techniques be employed during the
installation of the EC2."
It was my thought that avoiding the presence of loose metal objects inside an
electrical device that your life depends on fell into the category of
"needless to say".
Nevertheless, a cautionary note might well be worth adding. As also
stated in the first paragraph of the instructions,
" I want your project to succeed and your life to be a long and happy one.
"
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