The Boeing 737 MAX’s return to the skies faces a new hurdle.
U.S. and European regulators are at odds over some fixes to the plane’s flight-control systems, The Wall Street Journal reports, citing people familiar with the details. The issues may cause the European Union Aviation Safety Agency to withhold support when the Federal Aviation Administration clears the plane's return to the air, the report says.
Boeing didn't immediately respond to a request for comment from FOX Business.
The disagreement may further delay the 737 Max’s full return to service, which Boeing CEO Dennis Muilenberg has suggested will happen before the end of the year.
"We are making good solid progress on the software update to the airplane," Muilenberg said on Sept. 11 at the Morgan Stanley Laguna Conference in Laguna Niguel, California.
Final versions of the upgraded anti-stall software are in the planemaker's integration labs, simulators are being tested and Boeing expects the jetliner to be back in service early in the fourth quarter, he added.
“Once this is finalized and we certify the airplane, it’s going to be one of the safest airplanes ever to fly,” Muilenburg added.
The 737 MAX, the best-selling model in Boeing's history, was grounded in March after two overseas crashes that killed more than 300 people prompted scrutiny of its anti-stall software. Regulators demanded the planemaker devise a patch to prevent the software from acting on erroneous data and attempting to lower a plane's angle of ascent during takeoff.
Boeing didn't receive a single 737 Max order in the first half of the year, and the Saudi Arabian carrier flyadeal pulled an order for 50 Max jets in favor of rival Airbus in July.
The U.S. planemaker has 145 registered sales through August, the latest available period, and a net total of 55. Its shares fell 1.5 percent to $376.54 before the start of regular trading in New York.
Meanwhile, Airbus said Tuesday that it has extended its aircraft-sales lead over Boeing for 2019. The European planemaker sold 41 jets in September, bringing its total to 303 orders in the first nine months of the year. After subtracting cancellations, Airbus has 127 net new orders.