Dennis Muilenburg, president and CEO of the Boeing Company, faced lawmakers' calls to resign

Boeing Chief Executive Dennis Muilenburg faced another round of tough questions on Wednesday, with US lawmakers calling out the aerospace giant for not holding top leaders accountable after two deadly crashes.

At least two lawmakers called for Muilenburg to resign during a second day of congressional hearings into the Boeing 737 MAX following the crashes, which left 346 dead.

Muilenburg again apologized for the accidents, acknowledged some mistakes in the development of the MAX and expressed regret over the loss of life after visiting with family members of victims on Tuesday following a bruising Senate hearing.

"We are deeply, deeply sorry," Muilenburg said.

Muilenburg said the company fell short in a number of respects, including in the Maneuvering Characteristics Augmentation System, a flight handling system that has been implicated in both crashes and was not included in flight manuals—a point that has sparked sharp criticism from pilots.

Muilenburg said the company aimed to keep the manuals short and that they were designed for safety, rejecting the contention that Boeing's motivation was to limit training requirements to save money.

But lawmakers pointed to Boeing marketing material to airlines, which emphasized that the MAX could be flown with modest additional training.

"You say you are being accountable," said House Transportation Committee Chairman Peter DeFazio, who is leading the committee's probe. "I'm sorry, I'm just not buying that."

DeFazio also rapped Boeing for a "lack of candor," adding that "we know there was tremendous pressure on production."

Family members of those who died aboard Ethiopian Airlines Flight 302 hold photographs of their loved ones during Muilenburg's testimony

Pay cut?

Other lawmakers pressed Muilenburg on why he had not taken a pay cut. In 2018, Muilenburg's total compensation package was $23.4 million, according to a securities filing.

"Why are you not giving up any money?" demanded Representative Steve Cohen, a Tennessee Democrat.

Muilenburg said that his pay was set by the board of directors.

"You're saying you're not giving up any compensation?" Cohen said. "After these two horrific accidents that caused all these people to disappear, to die, you are not taking a pay cut. You are not accountable."

In a subsequent round of questioning, Muilenburg said he expected his 2019 bonus would be "zero" based on the company's performance.

Earlier this month, Boeing ousted commercial plane chief Kevin McAllister, the first major departure following the accidents.

The company also stripped Muilenburg of his title as chairman.

Muilenburg said he had not offered his resignation after the tragedies.

A document appears on an overhead display during Muilenburg's congressional testimony

"These two accidents happened on my watch. I feel responsible to see this through," he said.

"I grew up in a farm on Iowa and my dad taught me that you don't run away from challenges and this is a challenging situation," he said. "My responsibility is to stick to it and to help our team work through it and to get Boeing ready for the future."

Muilenburg pointed to the loss of the chairman title as an example of accountability and said he agreed because it gave him more time to focus on returning the MAX to service.

"I am responsible. I am also accountable," Muilenburg said during an exchange with Democratic Representative Rick Larsen of Washington.

"As additional reviews are complete, we'll take additional actions," Muilenburg said. "The flying public deserves safe planes."

Analysts have viewed the board's decision on Muilenburg's chairman title as a prelude to his eventual departure from the company, most likely after the MAX returns to service.

But Representative Debbie Muscarsel-Powell, a Florida Democrat, told Muilenburg he should step down now.

"Mr. Muilenburg, if you had any ounce of integrity, you would know the responsible thing is to step down," she said.