It was grounded worldwide after two tragic accidents. Now, regulators in the US have given it permission to fly again – but will it really be safe? Theo Leggett speaks to Mark Pegram whose son Sam was killed aboard the flight which crashed after take-off from the Ethiopian capital Addis Ababa in March last year. He also spoke to Ed Pierson, a former senior manager on the 737 production line at Boeing’s Renton factory, just outside Seattle, who gave testimony to the House of Representatives saying how months before the first accident, he had emailed his bosses, warning them how the pressure to produce new planes as fast as possible was undermining safety. In response to Mr Pierson’s testimony, Boeing insisted that the suggestion of a link between his concerns and the Max accidents was completely unfounded. It added that none of the authorities investigating the accidents had found that production conditions in the 737 factory had contributed in any way.The US regulator, the Federal Aviation Administration, has also come under fire.