Transcript for Investigators release report on crash that grounded Boeing's 737 Max
The investigation into the Boeing 737 Max it was a year ago this week when the second Max crashed in Ethiopia killing all on board announced today. Ethiopian investigators have released a new interim report on the crash our geo that need to as is here with Morgan in nineteen champ. Lindsay getting easy this is look this was a crash that led to the worldwide grounding of the 737 Max and now today. Ethiopian investigators blaming Boeing. For those design flaws of this as so many families remember their loved ones. One you'll hear. We begin tonight with a deadly plane crash the new Boeing jet that went down overseas and. The news that shook every traveler around the globe just six minutes after takeoff Ethiopian air flight 302. Plummeting near the Ethiopian capital of autos are blue box plane's shattered in pieces a 157. Killed including eight Americans. This seemed painfully familiar because it was the second Boeing 737 Max involved in a catastrophic crash in less than five months. In October 2018 lion air flight 610 also crashed off the coast of Indonesia into the Java city. Leaving heartbroken relatives as crews sifted through floating and underwater wreckage. For clues into what went wrong and with the crash of the Ethiopian air flight history repeating itself investigators going through the rubble this Ethiopian field turned graveyard is the first crash in Indonesia was initially blamed on pilot error despite the fact that just the day before. A pilot reported struggling to keep control of the same claim. But now the realization began flying around the globe something could be wrong with the plane itself. Once Boeing's fastest seller. In my mind there was such trust in the Boeing brands such trust in the ability of this company to build great safe airplanes that. Even after the second airplane went down with a very similar characteristics. Hard to think about wow maybe it wasn't designed plus one by one. Since taking clean out of commission and then US regulators to. We're going to be issuing an emergency order of pro immigration to ground all flights 8737. Max faith. 3737. Max nine. And this week a year later. 400 brand new Max planes are still sitting. Like untouched artifacts and Boeing after making adjustments is trying to convince the world the plane is safe. Paul drove him lost his entire family in the Ethiopian for a. She's my wife and my mommy and own new to a going to back. They heads to somehow conflict that you drained during those trying to mormons. Knowing duo quality and cost. In the last year those left behind going to Capitol Hill trying to prevent something like this from ever happening again. Tomorrow it can view of the going to be Arafat believes it can be real lives and your kids. Here's what investigators believe happened in both crashes a faulty sensor or sent bad data to a system called and cast the maneuvering characteristics. Augmentation system. Just look at how much bigger the engines on the Macs are compared to the previous 737 model which at the time was the best selling airliner. In certain circumstances the larger repositioned engines caused the Max to pitch not. In full trust the nose tended to point 24 artworks that and caste system designed to help stabilize the plane. But in this ABC news simulation watch the planes erratic behavior that faulty sensor. Cause the system to misfire forcing the plane's nose down over and over again even as pilots fought to gain altitude. Over 80% of all of mishaps and commercial aviation are caused by humans can making errors. It is the human being that is the problem not the airplane and what happened in the maxis. Boeing tried design something and that would help the human being rather than design something in that would help the machine to fly the machine better. The system was not mentioned in the plains manual while critical document for pilots in the year. But after the first crash the FAA issued a warning to pilots saying that incorrect sensor data could lead to loss of control and a crash. In the cockpit multiple alarms going off like this all. Potentially causing confusion in the cockpit the National Transportation Safety Board saying this was a factor in the crash. It's very understandable why they were overwhelmed. But that part of it gets covered when you do the basic emergency procedures and members of congress accuse the FAA of being too cozy with blowing. Saying the FAA failed to ask the right course chips. We've interviewed and spoken with FAA employees blowing whistle blowers among others these documents emails and interviews are crucial to our investigation. Which is uncovered a broken safety culture within Boeing. And an FAA that was on knowing unable or unwilling to step up regulate and provide appropriate oversight of Boeing. Lawmakers grilling Boeing accusing the manufacturer of putting profits over safety. But is troubling to hear that Boeing may have skirted the FAA's certification process over a desire by airlines to have more fuel efficient planes. But without pilot training. Boeing admitting it made mistakes Whiting we ground that aircraft collapse sooners to another strategy wouldn't happen if we knew everything back then that we know now we would have made a different decision but the company saying safety is and always has been its highest priority. The Max returns to the skies with the software changes to the MCAS function. It will be among the safest airplanes ever to fly. Boeing ultimately firing its then CEO Dennis Mullen berg even though he had every intention of staying at least two accidents happened. On my watch. I feel responsible to see this through the yearlong grounding costing Boeing and the airlines billions Boeing eventually shutting down the production line. And now tonight how does but we recover and hold a maximum ever fly again. The 737 Max or whatever it's called in the future will be a great airplane. It is going to take time. They're gonna have to earn the trust of the flying public just days ago when a preliminary report lawmakers concluded that production pressures design failures. And a lack of transparency from Boeing. Coupled with a failure of oversight from the FAA led to the two fatal plane crashes that killed contracts. Nearly 350. People mothers fathers sons and daughters. Who should still be alive. Yes so tragic now in just a few weeks Boeing plans to conduct whip FAA pilots the certification. Flight test. That is expected there in just a few weeks but they have months of work ahead Lindsay because. Boeing says that they do plan to fly the Max with passengers. Microsoft and over the weekend we learn of another potential setback yes a basically the FAA told Boeing that they need to make some changes to the max's electrical wiring but still blowing insist they plan to fly the plane in the sub. And so the report also suggests that the pilots tried to re engage the automated system right. Yeah an aviation experts every aviation expert we speak with Lindsay they basically say when you get that automated system and you have a problem you turn it off. You leave it offer in the new fly that plane manually that didn't happen here for some reason. The pilots turn that automated system back on and the automated system is what has the problem. Do you have any tens of pleasure to have you with us insane tonight.
This transcript has been automatically generated and may not be 100% accurate.