CHICAGO (CBS) -- Congress plans to investigate the FAA's approval process of Boeing's 737 Max 8 and Max 9 aircraft, amid reports agency managers pushed FAA safety engineers to delegate safety evaluations to Boeing and to speedily approve federal analysis of a new flight control system.
CBS News has learned federal authorities have told employees at Chicago-based Boeing and the FAA in Seattle to retain documents dealing with the approval process of the now-grounded jets.
The development comes as preliminary evidence shows striking similarities between two deadly crashes involving 737 Max aircraft in the past six months, including the Ethiopian Airlines crash that killed 157 people last week, and a Lion Air crash that killed 189 people in October in the Java Sea off Indonesia.
Thousands mourned the victims of the Ethiopian plane crash on Sunday, as 17 empty flag-draped caskets made their way through the streets of Ethiopia's capital.
The nation's transportation minister said early data from the black boxes retrieved from the crash showed a clear similarity to the crash of another Boeing 737 Max 8 in Indonesia in October.
Satellite data also showed the flight patterns of Ethiopian Airlines flight 302 and Lion Air flight 610 were very similar before both planes plunged from the sky.
Physical evidence found at the crash scene in Africa included the plane's "jack screw," which helps lower or raise the nose of the plane. It was set in a dive position, indicating there might have been an issue with the 737's automated flight control software.
Boeing has come under increased scrutiny following the two crashes. CBS News has learned federal authorities have told employees at Boeing and the FAA to retain documents dealing with the approval process of the Max jets.
Government officials with knowledge of the situation did not dispute on Monday that a Boeing official had received a subpoena to preserve records relating to the FAA certification process of the 737 Max.
The Seattle Times reported on Sunday, citing engineers who the paper said worked closely on the FAA approval process for the 737 Max jets, that FAA managers, "pushed the agency's safety engineers to delegate safety assessments to Boeing itself, and to speedily approve the resulting analysis" of a new flight control system installed on the planes, known as the Maneuvering Characteristics Augmentation System (MCAS).
The MCAS system was put on the Max jets to help avoid mid-air stalls but it has been linked to the crash of the Lion Air jet, and given the similar flight paths, there are concerns it may also have played a role in Ethiopia.
Boeing's pilot training also has been questioned. CBS News has learned U.S. pilots were given initial training of 56 minutes on an iPad, regarding the differences between new Max planes and older model 737s.
The FAA grounded all Max 8 and Max 9 aircraft last week, and the planes could remain grounded for weeks, or even months. The FAA has said the planes definitely won't be allowed to fly again until the software fix is installed and verified to address concerns.
In a statement, Boeing CEO Dennis Muilenburg said the company is finalizing its development of a software update for the Max aircraft, as well as a revision to pilot training to address concerns from the Lion Air crash.
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