Why Are Twins Passé?

On top of that, twin-engine safety, as it turned out, has proven to be somewhat elusive. Although successful returns to an airport with an engine feathered often go unreported, when a less-than-skilled pilot loses control of a single-engine twin, the accident tends to be horrific in outcome. So, the fatal accident rate after an engine failure is much worse in twins than in singles. Not only does the twin with wing-mounted engines require precise and correct flying when one engine quits, but any resultant crash will occur with exponentially more kinetic energy. Single-engine planes are, by and large, limited to 61 knots maximum stall speed in landing configuration; twins have no such certification requirement and may arrive at 90 knots even if flown into the ground under control. If you're looking to survive an accident, plan to do it in a single.  

Insurance underwriters are only interested in exposure to risk of loss and the cost of meeting outlays to cover claims. More seats, more expensive accidents, more chance of a pilot's skill not being up to the challenge of flying the twin---all of these mean insurance can be a problem. To be insurable, the aspiring multi-engine pilot will probably have to go through initial and recurrent type-specific training, even though they have satisfied the FAA by adding a multi-engine rating to their license. 

As much as anything, the decline in light-twin popularity may have stemmed from the "corporatization" of general aviation manufacturing. Airplane companies are no longer run by designers and pilots who are justly proud of the company's aviation portfolio, of which twins were a natural progression. Today's business-oriented management saw an excess of models overlapping in the product line and reduced the offerings to streamline operations. No longer does manufacturer advertising promote fast, flashy twins to jaded single-engine pilots, focusing instead on sensible singles. On paper, at least, most of the twin's work can be done with a big single.