(CNN)The passengers on the Lion Air 610 flight were on board one of Boeing's newest, most advanced planes.

The pilot and co-pilot of the 737 MAX 8 were more than experienced, with around 11,000 flying hours between them.The weather conditions were not an issue and the flight was routine.So what caused that plane to crash into the Java Sea just 13 minutes after takeoff?

More than two weeks after the catastrophe, investigators are still piecing together the clues.As they do, the focus has turned to Boeing, which allegedly failed to tell pilots about a new system feature implicated in the crash -- information that aviation analysts say could have possibly saved the lives of all 189 people on board.A lawsuit against Boeing related to the crash was filed Thursday. The parents of one passenger sued the company, claiming that the downed plane, a 737 MAX 8, had an unsafe design. The suit alleges Boeing failed to communicate a new safety feature that hadn't existed in previous 737s.Lion Air's operational director has accused Boeing of withholding information from pilots in the manuals about a safety feature that automatically lowers the airplane's nose to prevent or exit a stall.Boeing Chief Executive Dennis Muilenburg told Fox Business Network on Tuesday that information was available as part of the training manual.On Wednesday, a Boeing spokesperson said in an email that the company could not "discuss specifics of an ongoing investigation" and that the company had "provided two updates for our operators around the world that re-emphasize existing procedures for these situations.""We are confident in the safety of the 737 MAX. Safety remains our top priority and is a core value for everyone at Boeing," the spokesperson said.CNN has spoken to nine aviation experts, including pilots who fly the 737 MAX 8 planes, about the crash. While they all emphasized that only a complete investigation will give a full picture of what actually happened in the cockpit that morning, all have concluded that, in one way or another, Boeing's actions fell short -- leaving not only the families of the victims shaken, but also the aviation industry.Boeing declined to comment for this article, referring CNN to its most recent statement cited above.

A facelift

In recent years, Lion Air, the popular Indonesian budget carrier, had given itself a makeover.The privately owned carrier was the first airline to put Boeing's 737 MAX 8 -- a more efficient and environmentally friendly upgrade of a jet introduced in 1967 -- into service. According to Boeing, the Max jets are said to be 10% to 12% more efficient than their predecessors.In 2011, Lion Air announced a $21.7 billion order for 230 of the single-aisle, twin-engine jets -- the largest single order for commercial jets in its history at the time, according to Boeing.Lion Air became the first airline to put the 737 MAX 8 into service, and later started buying more versions -- the 9 and larger 10 in a $6.24 billion deal this year.Those upgrades may have signaled a bid by Lion Air to rectify its spotty safety record over the last decade, including a 2013 non-fatal crash and a ban from European and US airspace between 2007 and 2016.The European and US bans have since been lifted, with the international civil aviation organization giving the airline its top rating in terms of safety this year. The MAX 8s have been a visible part of that boost.But with any new fleet, pilots must undergo additional training."Generally speaking, when there is a new delivery of aircraft -- even though they are the same family -- airline operators are required to send their pilots for training," Bijan Vasigh, professor of economics and finance at Embry-Riddle Aeronautical University, told CNN.hose training sessions generally take only a few days, but they give the pilots time to familiarize themselves with any new features or changes to the system, Vasigh said.One of the MAX 8's new features is an anti-stalling device, the maneuvering characteristics augmentation system (MCAS). If the MCAS detects that the plane is flying too slowly or steeply, and at risk of stalling, it can automatically lower the airplane's nose.It's meant to be a safety mechanism. But the problem, according to Lion Air and a growing chorus of international pilots, was that no one knew about that system.Zwingli Silalahi, Lion Air's operational director, said that Boeing did not suggest additional training for pilots operating the 737 MAX 8. "We didn't receive any information from Boeing or from regulator about that additional training for our pilots," Zwingli told CNN Wednesday."We don't have that in the manual of the Boeing 737 MAX 8. That's why we don't have the special training for that specific situation," he said.Investigators are examining whether an angle of attack (AOA) sensor on the outside of the Lion Air plane transmitted incorrect data that could have triggered the MCAS to force the plane's nose down.An AOA sensor is an instrument, similar to a small wind vane, that sits outside the plane just below the cockpit and sends information to its computers about the angle of the plane's nose relative to the oncoming air. The sensor helps to determine whether the plane is about to stall and dive.Investigators said that the day before the crash, the jet experienced problems with its AOA sensor, which was replaced. The last four flights -- including, crucially, the flight that crashed, according to Soerjanto Tjahjono, the head of Indonesia's National Transportation Safety Committee (KNKT), also had problems.On Wednesday, the Wall Street Journal reported that Southwest Airlines, a US carrier that also has a fleet of MAX 8 planes, replaced two malfunctioning AOA sensors, during the three weeks before the Lion Air crash.

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