Boeing reported on Thursday that Boeing 737NG operators have grounded a total of 38 of the narrowbodies as of October 9 after inspections of the wing-to-fuselage attach points uncovered cracks in assemblies—called pickle forks—that connect the airplane’s wing spars to the fuselage. Brazil's Gol accounts for 11 of the grounded NGs, meaning that, including its still grounded 737 Max jets, it has removed from service 14 percent of its fleet. In a written statement, Gol said the grounding would affect 3 percent of its customers through December 15.

For Southwest Airlines, the two grounded NGs account for a much smaller proportion of the airline’s 750-strong 737 fleet, resulting in a negligible effect on its schedules. A more significant disruption involves the 34 grounded Max jets, which will remain out of service until at least January 5.    

Southwest reported it had completed inspections of all the pickle forks in airplanes subject to a seven-day deadline in an FAA airworthiness directive.

“During our inspections of the high-cycle NGs, we did not find abnormalities on the vast majority of our inspected fleet but did identify signs of pickle fork cracking on two aircraft,” it said. “Southwest has removed the two aircraft from our operation and reported the findings to Boeing and the FAA. The aircraft will remain out of our schedule until the issues have been fully resolved. Safety is always our uncompromising priority, and our technical operations team is now focused on completing inspections of the remaining portion of the 737 NG fleet covered by the AD.”

In a statement issued Thursday to AIN, Boeing said it continues its analysis of the inspection findings to develop a repair plan. 

"As of October 9, airlines globally have completed 810 inspections on their 737NG fleets with 38 findings," said a Boeing spokesman. "Those airplanes with inspection findings will require repair and replacement of the affected parts. Boeing is actively working with customers that have airplanes in their fleets with inspection findings to develop a repair plan, and to provide parts and technical support as necessary. Boeing regrets the impact this issue is having on our 737NG customers worldwide and we are working around the clock to provide the support needed to return all airplanes to service as soon as possible."

The spokesman said the problem does not affect any 737 Max airplanes or the P-8 Poseidon military variant of the 737-800.