Mailing List flyrotary@lancaironline.net Message #50418
From: Al Wick <alwick@juno.com>
Subject: Re: [FlyRotary] Re: Ut-Oh...
Date: Wed, 17 Mar 2010 04:39:44 -0700
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
 
----- Original Message -----
Sent: Monday, March 15, 2010 8:20 AM
Subject: [FlyRotary] Re: Ut-Oh...

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? 

 

Can't argue with any of your statements above. However, you're using "slippery slope" argument. Implying that ANY change will be too complex. Since we can't stop the pilot from pulling mixture, then we shouldn't take action on other risks?

 

 In order to install a proper fix, you have to consider every possible scenario. 

 

Agree agree agree. Very important from my experience. But we always want the real world failures to trump theory. So I encourage taking action on the failure risk, but give thought to unexpected effects. One option is to place a tiny button next to the "shut down knobs" (my name for cold start and mixture knobs). Press button to enable massive mixture changes. So if you touch the button, you now have 10 seconds to make huge mixture changes. If you don't press the button, only small mixture changes are enabled. This would dramatically reduce flight risk, but would only affect users in distant future.

Encourage you to take a look at other applications which successfully prevent these oop's. Some use spring loaded knobs, you have to pull and turn to make change. Some use software or hardware to limit the change. And then of course there are the hugely successful automobile ECU's.

 

 

 

Regards

-al wick

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