X-Plane – 9 Piper PA-23 Aztec. The Piper PA23, named Apache and later Aztec, was an American twin-engined monoplane, the first twin-engine aircraft built by Piper Aircraft. Declining sales of the Apache prompted the redesign dubbed PA-23-250 Aztec, with 250 hp (186 kW) Lycoming O-540 carburetor engines. These first models came in a five-seat configuration which became available in 1959. The plane comes in four liveries. Thanks to Chris Wraight for the sound files. By Jacques Brault.