The relationship between Boeing and the Federal Aviation Administration, which has set the global standard in aviation safety for decades, will come under unprecedented scrutiny this week after two deadly airline crashes. Both accidents involved a Boeing jet green-lighted by the U.S. regulator, which relied heavily on safety assessments made by Boeing employees. In a startling break from the past, other nations and airlines grounded the Boeing 737 Max en masse after the second fatal crash this month while the same model of plane continued to carry tens of thousands of passengers a day in the United States. This week, Congress joins the investigation into Boeing and the FAA.