Transcript for Boeing 737 Max 8 and 9 jets grounded

And we will start here with our top story of the grounding of those. Boeing 737 Max eight planes the US government has now made it official let's get right out to David Curley he's live at Reagan international airport as he covers transportation forest David take us through the timeline here because a lot of people say you know what the FAA just took too long and David I see that you're actually invite our Washington bureau there. I am at the bureau. There's a real question about. Whether the FAA took too long or not what the agency will say is that they base their decisions on evidence and the evidence changed overnight. From Tuesday it into Wednesday and so they ordered the grounding of the 72 aircraft here in the United States but what's gonna tell us whether they've made the right decision. Or the wrong decision. Is happening in Paris right now. The two black boxes from the Ethiopian crash are in Paris at the is safety investigation bureau there. To be read out to extract the data. Which should tell us are these two crashes the Ethiopia crash on Sunday and the lion air crash in Indonesia back in late October. Are there related the reason the FAA decided to ground as it if you look at the flight data that they have right now the path of the two aircraft. They basically were going. Up and down an up and down and they saw enough similarities and the time between some of those dips that they said okay we're not sure this is connected but they look similar so let's go ahead and ground. There will be there are experts who will tell you that grounding was premature. Because the first accident they believe was based on. Poor maintenance and pilot error. And that there's no proof that the second crash what actually caused so. I mean geo the bottom line is is there something wrong with this jet. Are we dealing with pilot air. And basically that black box the data from that black bloc says is what you're saying it may tell them what exactly happened. Before this plane went down. Yen to about two boxes actually so flight data is gonna tell us exactly what the pilots were doing what the plane was doing. Which systems were engaged with sit which systems were not engaged and what the pilots were talking about as this plane was going up and down as we said where they. Do you know. This could be anything from was our fire in the cargo hold was there something else going on in the cockpit. Mean we really don't know yet that did that the problem is this is a brand new jet we've seen two crashes in less than five months. And that these dips right after takeoff looks similar so let's figure it out in that data and the voice recorder. Should tell us and there's a chance GO. That we could have some answers today. All right David Curley live in Washington David we will see tonight on world news tonight at New York.

This transcript has been automatically generated and may not be 100% accurate.