Boeing is seeing a significant improvement in production flow at its 737 MAX factory, its new commercial planes chief said on Sunday, as the U.S. planemaker battles to overcome a safety crisis.

Speaking to reporters in London ahead of this week's Farnborough Airshow, Stephanie Pope said the changes Boeing was making to the Seattle-area factory were significant.

"This isn't minor change. This is transformational change," she said in her first remarks to media since being appointed earlier this year.

"We are a stable company," she added

Boeing is mired in crisis after a cabin panel on a 737 MAX 9 jets blew off midair in January, prompting a slowdown in production of its top-selling plane as well as heightened regulatory and legal scrutiny.

Boeing has also agreed to plead guilty to a criminal fraud conspiracy charge over a probe related to two earlier fatal 737 MAX crashes, the Justice Department has said in court filings. Pope declined to comment on a plea deal.

The company is seeing a "significant improvement in the flow of our 737 factory," Pope said, while acknowledging that Boeing has disappointed airline customers.

She said Boeing would need to be more predictable on deliveries after production slumped.

The Federal Aviation Administration in January took the unprecedented step of barring Boeing from increasing production beyond 38 MAX planes per month until it is satisfied with the planemaker's quality and manufacturing improvements.

"This isn’t about safety and quality versus schedule," Pope said. "These are not competing priorities."

Speaking at the same event, the head of Boeing's defence and space division signalled that unit was having a tough quarter.

"We had a good start to the year, but this quarter you'll see to be significantly challenged," Ted Colbert said.

"It'll look like it looked in the third quarter of last year as we go through some more challenges on the fixed price development programs," he said.

Pope became CEO of Boeing's commercial division as part of a broader management shakeup that will see CEO David Calhoun stepping down by year's end.

Pope has been cited as a possible contender to take the reins of Boeing, although the company is facing calls from airlines and some industry officials to choose a leader with an engineering background which she lacks. Pope said she was focused on her current role "24/7."

She reiterated that the company expects to bring MAX production back to a rate of around 38 a month by the end of 2024.

Pope also said the planemaker had settled on a design to address a engine anti-ice system that has significantly delayed certification of the 737 MAX 7, and suggested a fix could be completed by next year.