Thanks Paul for some very interesting data and thoughts, esp on the relative merits of certified vs experimental safety.  I've spent a lifetime in airplane and missile design and have seen lots more of what you described, i.e., failures by certified systems, certified systems misunderstood by pilots, and completely unanticipated types of failures (a 737 ingesting a horse on takeoff; a 727 engine that blew up and fell off when blue water from the front lav leaked through a bad seal, froze on the outside of the fuselage, cracked off and went into the engine inlet).  

Industry insiders, at least the good ones, have no illusions about the meaning of certification.  It means that the product went through some design reviews, manufacturing process steps, and tests -- all conducted by *people*, ultimately.  And then it gets turned loose on an unsuspecting world for ultimate testing -- fleet ops.  That's why Consumer Reports will never recommend a new model of any car, even if it's made by Honda or Toyota -- until they have a year or two of test data in the hands of ordinary car owners.

General aviation equipment suffers from having such a small number of units and so few hours of fleet use compared to just about any other complex product -- cell phones, computers, cars, even airliners.  So we are constantly in a state of beta test, even with certified equipment.

So I guess the ultimate point is that we are the testers, whether the equipment is from Joe's Hobby Garage or Continental or Acura.  Complacency kills, so I have a couple of rules of my own:

1.  Every mechanic / tech / designer out there is trying to kill me.
2.  When something breaks, Rule 1 is Fly The Airplane.

I'll be staying tuned to all you guys whose heads are in the game, I'm pretty impressed with LML and will let you all know anything interesting that happens with my Legacy / G900 / Sorceror / IO550.  PS -- I went with electric backup gyro, but will freely admit that there is a slightly higher probability that it will fail at the same time and for the same reason as the G900, compared to a vacuum powered gyro.  But I think its still a very small probability -- I avoid lightning -- and I didn't want the weight and maintenance burden of a vacuum system because they do fail regularly.

Charley Brown  N550KC  80 hours

On Jan 19, 2012, at 2:48 PM, paul miller wrote:

I'm really intrigued by the overall discussion on safety.   ......