What killed the piston twin? That’s easy. It was the piston single.
All types of piston airplane production have faded over the last 30 years but the piston twin has nearly vanished. Only the Beech Baron 58 and Piper Seneca V remain in production by the major manufacturers. On the used market piston twin values have plunged.
Many blame safety concerns for the piston twin decline. There is no question that the pilot of a piston twin faces a more demanding control situation after an engine failure than does the pilot of a piston single. Insurance companies recognize this fact and demand a higher level of training and experience for the twin pilot compared to the pilot in a piston single of similar value and performance.
There is also the unavoidable higher cost of the twin. You need to maintain and feed that second engine. A twin doesn’t cost quite twice as much to own and operate as a single, but the difference is very substantial.
But cost and safety concerns are nothing new. The twin has always cost more to fly, and there were always the higher demands on the pilot if an engine failed. What has changed is that the single can now offer nearly all of the capability that was once exclusive to the twin.
One of the most important reasons to buy a twin years ago was to get ice protection. Most twins were available with deice boots and protection for the propellers, but on a single only a heated pitot—and maybe a heated prop—were offered.
In the late 1970s Cessna changed that when it installed ice protection on the 210 and certified the airplane for flight in icing. Anybody who has encountered significant ice in a 210 may wonder if the airplane really has enough ice protection, but the flood gates were open. Ice protection on a single was once unthinkable, but quickly became an option pilots demanded on any high performance single. And the weeping wing TKS system became more attractive and available than boots on many singles.
Another important reason for the twin was the availability of weather radar. The nose cone of a twin was the only available spot to put a radar and radar was the only thunderstorm avoidance technology available during the heyday of the piston twin.
The first dent in the twin’s lead in weather avoidance came when Paul Ryan introduced the Stormscope in the mid 1970s. The early Stormscope didn’t work all that well, but it was better than nothing which is what piston single pilots had been flying. And subsequent generations of the Stormscope were much better at showing pilots where lightning and thunderstorms were located relative to the airplane.
Then Bendix developed a small radar it called the WeatherScout RDR-160 that could be mounted in a pod located on the wing of a single. The pod added very little drag and gave the piston single pilot as good a view of the weather as available in a piston twin. Of course, satellite weather changed everything by sending down near real time radar to any airplane so every pilot can have up to date weather in flight.
Piston singles also gained performance with more powerful engines. Pressurization, once the exclusive purview of twins, also became available in singles. Air conditioning was another option once reserved for twins that found its way into singles. Plush interiors, cabin entertainment, even airstair doors, migrated from twins to singles.
What’s left exclusively for the twin is the capability to continue to fly under most conditions after one engine quits. When I say most conditions I mean the vast majority of every flight that takes place in the minute or so after takeoff. Will a piston twin be able to continue safely if an engine fails shortly after liftoff? Maybe is the only accurate answer. But climb to 1,000 feet or so and any reasonably competent pilot should be able to get a piston twin back to a runway if an engine quits.
But engine failure has faded as a pilot concern. When I started in this business almost 40 years ago the Lockheed JetStar was a favorite business jet among the old timers because it had four engines while the other bizjets all had two. For the generation that pioneered transportation flying you just couldn’t have enough engines. But it has been decades since even Boeing designed a new airplane with more than two engines, even though those twins are bigger than anything the old timers ever imagined possible.
So why do I still fly a twin? Well, because I own it and have for 23 years. It’s worth more to me than anybody shopping for used airplanes. And Lake Michigan is about one mile from my home airport. Engines don’t fail often, but over that dark frigid water once would be enough if you only had one.