A father whose five family members, including three children, died when a Boeing 737 Max jet crashed in Ethiopia in March, accused the company of “utter prejudice and disrespect” and warned there would be more deaths unless action is taken.

Paul Njoroge’s wife, mother-in-law and three young children died when Ethiopian Airlines flight 302 crashed on 10 March, shortly after takeoff from Addis Ababa. All 157 passengers and crew members aboard were killed.

The congressional hearing in Washington at which Njoroge spoke comes in the wake of two fatal crashes involving Boeing 737 Maxes that killed 346 people and which have triggered investigations and lawsuits around the world.

In blistering testimony, Njoroge said Boeing’s focus on share price and profits “at the expense of the safety of human life” and its cosy relationship with its US regulator, the Federal Aviation Administration (FAA), had led to the two crashes and cost him his family.

In prepared notes, Njoroge wrote: “I miss their laughter, their playfulness, their touch. I am empty. I feel that I should have been on that plane with them. My life has no meaning. It is difficult for me to think of anything else but the horror they must have felt. I cannot get it out of my mind.”

Unless Boeing’s conduct is addressed “another plane will dive to the ground killing me, you”, Njoroge told Congress.

Njoroge said Boeing had moved to blame “foreign pilots” after a Lion Air 737 Max crashed into the Java Sea in October 2018. He said Boeing’s insinuation of pilot error allowed it to keep flying the plane – and that led directly to the death of his family.

As investigations have continued, it now appears that a software system called MCASs, which is designed to automatically prevent stalling, was central to both crashes.

Njoroge said: “I speak for all of the families who lost loved ones whom they will never see again and who were tragically torn from their lives because of reckless conduct on the part of so many. Particularly Boeing, a company who became steadfast in its single-minded quest to place blame on so-called ‘foreign pilots’.”

He went on: “In Canada, Independence Day was celebrated on 1 July. I stayed buried in my little house, in my grief, hearing the sounds of celebration and fireworks in the sky. But all I could think about was the 737 Max struggling to gain height and eventually diving to the ground, killing my whole family and 152 others.”

Boeing’s fleet of 737 Maxes remain grounded. Last month, US regulators said they had found more problems with the airplanes after a simulator test, leading United and Southwest airlines to extend their bans on flying the 737 Max.

The company appears to be planning to rebrand the plane before it is given the all-clear. This month, a 737 Max due to be delivered to Ryanair was photographed with 737-8200, instead of 737 Max, painted on its nose.