Boeing officials "inappropriately coached" test pilots during recertification efforts after two fatal 737 MAX crashes killed 346 people, according to a lengthy congressional report released on Friday.

The report from the Senate Commerce Committee Republican staff said testing this year of a key safety system known as Maneuvering Characteristics Augmentation System (MCAS) tied to both fatal crashes was contrary to proper protocol.

The committee concluded Federal Aviation Administration (FAA) and Boeing officials "had established a pre-determined outcome to reaffirm a long-held human factor assumption related to pilot reaction time ... It appears, in this instance, FAA and Boeing were attempting to cover up important information that may have contributed to the 737 MAX tragedies."...