Originally Posted by
Devil 49
Twins are more complicated and there's no way around the complexity. Integrating two engines, two generators, etc., will always present more opportunity for mistake. Mistakes cause crashes. High side/low side fuel control failures, for instance... or generator failures- at least in the old designs I flew- what's on which bus? What will you lose?
I've flown for operators who regarded the second engine as the ability to safely fly in reduced weather. No better IFR equipment, just a second engine.
Devil, this is the factor most people either miss or choose to ignore. The added complexity of transmission drives, clutches, freewheels etc. in conjunction with electrical and hydraulic power generation all add multiple failure paths. In a complex system, the reliability is based entirely on the most unreliable component, not the most reliable component, which is usually the engine. There are plenty of circumstances where a twin is a safer option, but not necessarily a more reliable option. I've always felt more comfortable operating over water with two engines rather than one, but my pucker factor was then focused on multiple systems rather than a single engine tacho.
There is no right answer to this perennial question, it's about risk, hazards and mitigation, and every operation will be different. Whatever works for you is the answer, or actually, whatever works for the person who paid for the airframe.