On its own, Boeing’s strong finish in 2023 would be a bullish sign for the year ahead, as the 737 Max is the company’s biggest source of revenue. But its prospects have been shrouded by the Jan. 5 accident on Alaska Airlines Flight 1282, which led regulators to ground most of the Max 9 fleet.

National Transportation Safety Board Chair Jennifer Homendy said Monday she’s considering broadening the agency’s probe to look deeper into the manufacturing process after initial airline inspectiions showed loose or wrongly installed fasteners in multiple planes.

“We do see the latest incident as eroding the fragile confidence that has been built around the 737 Max franchise,” Ron Epstein, an analyst with Bank of America, told clients before the results were announced. “In our view, Boeing needs to tread carefully and cautiously through this potential reputational minefield.”

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Boeing’s bumper December included 68 Dreamliner orders. Of the total monthly bookings, 201 were for unidentified customers — in the past often a signal for activity by China. The activity helped to spur the planemaker to its highest annual sales total in nearly a decade: 1,456 gross, or 1,314 planes net of cancellations and conversions.

Boeing delivered 67 airplanes in December, including 45 of its 737 family and 22 widebodies, according to a statement Tuesday. For the full year, the manufacturer handed over 396 of its 737 model, within the range of its target of 375 to 400.

The planemaker had to lower its annual 737 goal earlier in 2023 because of a problem with holes drilled in the aft bulkhead by supplier Spirit AeroSystems Holdings Inc., the former Boeing unit that makes most of the fuselage for the narrowbody jet.

One key question is whether Boeing will be forced to temper its plans to speed up 737 production this year, according to Seth Seifman, analyst with JPMorgan. Investors have sold down Boeing stock since Jan. 5, when Flight 1282 lost a fuselage panel while climbing over Portland Oregon.

With rival Airbus SE — which reports later this week — running out of delivery slots until the early 2030s, a sales fall-off at Boeing would seem to be less of a risk.

“However, if the hits to the program do keep coming, at some point, the flying public may lose confidence in the 737 Max, which could ultimately impact sales,” Epstein said in a Jan. 7 report.