antas Airways Ltd and Southwest Airlines Co are stepping up checks for structural cracks on Boeing Co 737 NGs after discovering problems with planes that did not require urgent inspections, airline sources say.
The cracks are on what is known as the "pickle fork" - a part that attaches the plane's fuselage, or body, to the wing structure.
Repairing the cracks requires grounding the airplane, with remedial work costing an estimated $400,000 per aircraft, according to aviation consultancy IBA.
Boeing on 11 October said 38 planes worldwide had been grounded after urgent checks but has not provided a further update.
The issue surfaced while the newer 737 MAX model is grounded globally following two deadly crashes.
