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