heattreatment-batch-as-finishing-problem-indicationTakeoff rotation and liftoff proceeded normally. As soon as the landing gear was retracted, the crew heard a loud bang and the aircraft veered to the right. The left engine had failed.It was later discovered that a rotor blade in the high-pressure turbine had fractured. The aircraft landed hard on the runway. Turbine blades that can be attributed to a heat-treatmentbatch are a strong indicator of a finishing problem. Inthis case there is evidently a connection with unusualtraces of the element bismuth in the blade material. 9 rotor blades of the firsthigh-pressure turbine stagehad primary fractures. Extensive damages occurredon all following blade rows.A possible explanation for the contamination of the blade material withbismuth during heat treatment:Holding block for workingon the blade root, which is made from a low forged bismuth alloy Cast workholding material residueDuring heat treatment:Diffusion of bismuth intothe blade material throughadhering residue and/ormetal vapors Aircraft 15 m above ground