Families still grieving after deadly Boeing 737 Max plane crashes claimed the lives of their relatives are expected to testify on Capitol Hill for the first time Wednesday morning. Two recent crashes in Indonesia and Ethiopia left 346 people dead, and there's growing concern the grounded aircraft may not be ready to fly again until 2020.

The House Transportation Committee has been hearing from various stakeholders involved in the 737 Max grounding – but until Wednesday, not from families, prompting some to demand a chance to be heard by lawmakers.

"The families need to be involved in the process," said Michael Stumo, the father of one of the victims of the Ethiopia Airlines crash. Minutes after Flight 302 took off this March with his daughter Samya on board, the plane crashed, killing all 157 people on the plane.

"Two pilots don't have the strength to overcome what the plane is doing to try and ram it in the ground, in this case at 500 miles an hour," he said, "where our daughter's body parts got mixed with other people's body parts and plane parts and mixed with the dirt."

Investigators believe a faulty sensor triggered the plane's anti-stall system, pushing the plane into a dive. A similar set of circumstances is believed to be the cause of the Lion Air 737 Max crash last October in Indonesia, which killed 189 people.



"We need to see the pain and the families that lost people, because that is the price," said Samya's mother, Nadia Milleron. "They keep talking about the price from Boeing, and how much they are losing in terms of revenue -- this is the human cost."

Testifying alongside them will be Paul Njoroge, who lost his entire family when Flight 302 fell from the sky. He says he's so grief-stricken that he hasn't been able to bring himself to go back to his family's Canada home.



"My family died because of Boeing's negligence, arrogance, management." Njoroge said. "What I call management dysfunction and lack of internal oversight within Boeing."

Boeing CEO Dennis Muilenburg spoke with "CBS Evening News" anchor Norah O'Donnell about the crashes in May. "Our purpose is to understand what happened in the accidents so we can make flying even safer…." Muilenburg said. "And in some cases, that means understanding that leads us to improvements in the airplane design, such as the software improvement. And we own that, we have that responsibility."

Boeing software engineers are working to resolve design issues with the 737 Max. But there's concern the grounding could stretch into 2020.

The families say they don't want to see the Max fly again until all investigations have been completed. Already, the Max has been grounded longer than any other fleet of airplane in the FAA's history. Boeing told CBS News that it regrets the loss of life, and has continued to apologize to the families for the accident.

