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Old 19th Apr 2019, 14:22
  #55 (permalink)  
Join Date: Dec 2008
Location: N/A
Posts: 822
"There are many holes in the cheese that needed to line up. Some of them are already there, now, in our own working environments. Finding the holes and plugging them is the mission."
2 layers of cheese with 2 holes each is easy to avoid holes lining up
4 layers with 300 holes each is very difficult.

Tight on fuel to assure engine accountability during takeoff is clearly a false safety trade-off.
Complexity leads to pilot error. Pilot error is about 4/5ths of accidetnts.
Complexity increases the probability of System Failures. About 1/5th of Fatal accidents are system failures.

Engines 1%.
Complexity kills. (to paraphrase Occam: "a helicopter should have a single reliable engine")

There is a level of engine reliability at which the extra risks (of 2 engines) are not worth it.
Anyone got a handle on what that figure is? IS THERE AN EXPERT out there?
Should be easy to calculate. Probably somewhere around the 10^-3 to 10^-6 mark. Trying to improve on that risks shooting one's self it the foot with an overcomplicated gun.

"a pilot who understands the EC135 fuel system should NEVER end up with fuel starvation provided..."
and the number of pilots that don't is? : 1 per 100,000? 1 per 1000? 1 per 10?
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