By David Shepardson and Tim Hepher
WASHINGTON (Reuters) -Boeing Co Boeing (NYSE:BA) delivered 35 airplanes in October -- down from its 51 deliveries in September that tied its June performance, when it exceeded the 50-plane threshold for the first time since March 2019. The Arlington, Virginia-based planemaker said it booked 122 new orders in October, including 106 737 MAX airplanes and 10 787-9 airplanes. That was up from September when it booked 96 new airplane orders with six cancellations. The October deliveries included 23 737 airplanes, which was down from 37 737s in September. Boeing Commercial Airplanes chief Stan Deal said last week at an investor conference that the decline in 737 MAX deliveries was the result of its quality management system catching "a defect in the fuselage, two defects and delayed deliveries." Deal said Boeing would "recover on that quickly. We can surge and we will recover for our deliveries at the end of the year, but that adverse quality which we have to manage out of the system was an impact." Boeing has delivered 363 airplanes in the first nine months of 2022, including nearly 300 737 MAXs. Boeing's orders net of cancellations for the year rose in October to 550 from 428 and its commercial backlog rose from 4,354 to 4,441 orders. Boeing faces a late December deadline for the Federal Aviation Administration (FAA) to certify the MAX 7 and MAX 10 under existing rules. After that date, all planes must have modern cockpit alerting systems to be certified by the FAA, which would mean significant delays for the new MAX airplane deployment unless Congress grants a waiver to extend the deadline. Boeing Chief Executive Dave Calhoun said last month he is confident Boeing will get an extension.