July 2005- One time-tested way to create a light twin is to take a single, remove the engine, and replace it with two engines on the wings. Sometimes the engines are smaller than those on the single—as in Piper’s Twin Comanche. Sometimes the engines are as powerful as that on the single—as in the Beech Baron.
Piper took the first approach with the PA-34 Seneca: it’s basically a Saratoga airframe with the 300 hp single engine replaced by two 200 (later 220) hp wing engines. The result is one of the longest-running twins in General Aviation.
The original Seneca was introduced in 1972, and you can still buy a brand-new Seneca V from Piper today. The original PA-34-200 Seneca had some problems, notably a low single-engine service ceiling.