Fixing a previously undisclosed 787 design flaw has now emerged as a contributor to Boeing's decision to freeze shipments from suppliers until early June.

Shear ties, which affix the fuselage frames to the skin of the aircraft, now require replacement or rework, after the initial design failed to take into account thermal fatigue loading of the parts.

The parts in question are located in the aft most part of the fuselage, inside sections 48 and 48 aft, which is the tail cone of the 787.

The problem, which was discovered in December, found that repeated cooling and warming of the unpressurized Section 48 and 48 Aft, the shear ties, those of which are made of aluminum, can pull away from the skin of the fuselage, potentially compromising the structural integrity of the aircraft.