It’s a standard thing in aviation. The companies that make “airplanes” are usually not the ones that make airplane engines that go on those planes. For big airl

It’s a standard thing in aviation. The companies that make “airplanes” are usually not the ones that make airplane engines that go on those planes. For big airliners the engine makers are GE, Rolls Royce and Pratt and Whitney. Same concept applies to small general aviation aircraft where the two big engine makers are Lycoming and Continental Aerospace. The engines are still type rated for the specific aircraft. Some aircraft might only have one engine type rated so there isn’t much choice. Others might have multiple engines to choose from, from multiple manufacturers. That’s the case with many commercial airliners.