Airbus A330 and A340 operators have been ordered to replace main landing-gear bogie beams after the beam in an A340-600 fractured prematurely during ground load tests.
In an emergency directive the European Aviation Safety Agency said the fracture resulted from high tensile standing stress following a "dry fit axle assembly method".
The problem has been mitigated with a "grease fit axle assembly method", said EASA in the directive.
But analysis shows that two specific main landing-gear bogie beams are "more likely" to suffer from standing stress, generated by dry-fit axles, because they are stiffer between the axle sockets.
These specific beams are not fitted on A340-500/600s but are found on A330-300s and A340-200/300s.
"Fracture of a main landing-gear bogie beam under high speed could ultimately result in the aeroplane departing the runway, or in the bogie detaching from the aeroplane, or main landing-gear collapse," said EASA. It has revised the life limit of the bogie beams and ordered replacement of the parts accordingly.