This paper presents a computer-aided planning system that is capable of generating assembly sequences for aircraft frame assemblies. The representation scheme for aircraft frame assemblies is first described. Algorithms for the automated generation of assembly sequences are then discussed. The planning system takes assembly drawing and bill of material as inputs. In consideration of both the geometric and technical constraints in the planning stage, the system generates an assembly sequence as output. The system has been implemented using an object-oriented approach (C++) and a graphical user interface under MS-Windows. A spar subassembly is used to demonstrate the working of the methodology as well as the implemented system.