Southwest Airlines are stepping up checks for structural cracks on Boeing 737 NGs after discovering problems with planes that did not require urgent inspections, airline sources said.
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 and costs an estimated $275,000 per aircraft, according to aviation consultancy IBA. The are currently thousands of 737 NG planes in use by airlines around the world.
The U.S. Federal Aviation Administration (FAA) on Oct. 2 mandated checks of 737 NGs with more than 30,000 take-off and landing cycles – which typically correspond to the number of flights – within seven days.
The FAA said jets with 22,600 to 29,999 cycles must be inspected within 1,000 cycles. That, however, could take several months before an inspection is required.
Southwest found cracks in one with about 28,500 cycles, a separate source with knowledge of the matter said.
A Southwest spokesman said the airline has pulled three jets from service for pickle fork repairs but he could not confirm the number of cycles. The airline has complied with the FAA directive on inspections but is expanding checks to its entire 737 NG fleet, he added.
A Boeing spokeswoman said on Thursday that just over 1,000 planes had met the threshold for inspections to date, and of those fewer than 5% had issues.