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.
-al
wick