Eurocopter EC 130B4 crash near Palanca, Kilamba Kiaxi district, Luanda, Luanda, Angola

The EC130B4, belonging to an agricultural association, crashed onto a house and two parked cars while approaching Luanda. Both pilots were killed and a person on the ground injured. The INIPAT investigation determined the probable cause was uncoupling of the flexible joint between the engine shaft and the main gearbox transmission shaft. Contributing factors were the absence of some fastening bolts securing the flexible joint assembly to the engine shaft base, which overloaded those remaining; the failure of those bolts, causing the assembly to uncouple; vibration and torsional forces producing plastic deformation and shear failure of the few bolts present; and the resulting poor coupling between the transmission shaft and the engine shaft.