$Boeing(BA.US)$'s problems deepened as its jet programs suffered fresh setbacks early this year and the company faced challenges from supply-chain constraints and sanctions targeting Russia over its war on Ukraine.

Chief Executive David Calhoun defended Boeing's engineering culture as the aerospace giant reported a quarterly loss and tackles cost overruns as well as extended back-and-forths with regulators and lawmakers over some of its biggest programs.

Mr. Calhoun said regulators had become more rigorous in scrutinizing the company's planes, while challenges to its defense business stemmed from fixed-price contracts that left Boeing to pay for overruns.

I don't attribute our certification issues and timelines to engineering shortfalls in any way.

- Mr. Calhoun said on an investor call.

Chicago-based Boeing has lost its place as the world's biggest plane maker to Airbus SE, delivering far fewer planes over the past three years than its European rival.

The company reported a quarterly loss of $1.24 billion, worse than Wall Street analysts had expected, hit by more setbacks on its jetliner and military programs. Boeing said supply-chain issues and Russian sanctions also weighed on results.

Boeing shares closed down 7.5% at $154.46, valuing the company at $91.2 billion.

The company faces challenges with almost all its jetliner programs, while some of its big defense contracts continued to have cost overruns and generated more losses.

Deliveries of the 737 MAX are running behind plan, Boeing said, and hinge in part on regulatory approvals. China hasn't recertified the MAX jets to resume flights, and Boeing has still to secure approval in the U.S. from the Federal Aviation Administration for two versions of the aircraft.

Boeing again pushed back the expected first delivery of its new 777X twin-aisle jet until 2025, five years later than planned, though the company said it had moved a step closer to resuming deliveries of the 787 Dreamliner amid a prolonged freeze.

Boeing and other aerospace companies continue to struggle with supply-chain issues, but the U.S. company has wrestled with a range of other challenges on many of its commercial and military aircraft, including the planes that will serve as the next Air Force One.

The company said it would pause production of the 777X, which can carry around 400 passengers, and start booking charges of $1.5 billion to reflect the move. It also booked $312 million in extra costs on the 787 program, part of an expected $2 billion bill for delayed production.

Boeing did keep its guidance for free cash flow -- needed to pay down the debt it amassed to weather the pandemic -- to turn positive this year. It burned through $3.2 billion in cash in the latest quarter. Chief Financial Officer Brian West said there was no need to issue equity or additional debt.

Boeing took around $1.3 billion in charges on four of its biggest military programs during the quarter, including the VC-25B presidential jet, T-7A Air Force trainer, KC-46A aerial tanker and MQ-25 drone. The company cited supply-chain challenges and quality issues.

Mr. Calhoun said Boeing wouldn't bid the same way on future military deals. Mr. West said he expected sales at defense, its biggest unit, to fall slightly this year.

The company also booked $212 million in asset impairments and other costs related to sanctions on Russia.

Sales in the quarter fell 8% to $14 billion, with analysts expecting $16 billion. The adjusted per-share loss of $2.75 compared with the 25-cent loss consensus among analysts polled by FactSet.

Boeing hasn't provided detailed financial guidance in almost three years but plans to hold an investor day in the fall. Analysts had expected Boeing to rebound to a $2.7 billion profit this year after losing $4.3 billion in 2021 and almost $12 billion in 2020.