Solution methods for the balancing of jet turbines

Turbine balancing is an important and regular maintenance operation at airline companies. As a result of manufacturing inaccuracies, variations occur in the weights of the blades that can, in turn, lead to significant out-of-balance forces on the engine. The overall time required for balancing can be decreased significantly if the best placement of turbine blades is first determined mathematically. This problem is formulated as a variation of the quadratic assignment problem and a number of solution schemes are investigated. A neighbourhood search algorithm is found to outperform the other solution approaches significantly when applied to data from a major South Pacific airline. The neighbourhood search algorithm can be combined with various strategies to initialize starting points. The use of starting points obtained from a Lagrangean dual scheme is shown to improve results for large problems.