Washington — Boeing's pilot training was under scrutiny Monday as investigators analyzed data from the Ethiopian Airlines 737 Max 8 jet that crashed outside Nairobi, killing 157 people. CBS News has learned that U.S. pilots were initially given 56 minutes of training, on an iPad, about the differences between the new Boeing Max planes brought into service in 2017, and the older 737s.

That information came as officials in Ethiopia said the flight data recorder — one of the doomed Flight 302 jet's black boxes — showed "clear similarities" to the crash of a Lion Air Boeing 737 Max 8 in Indonesia last October.

That assessment was confirmed by the French accident investigation agency BEA, which opened the black boxes and downloaded the data to hand over to the Ethiopian team leading the probe.

"During the verification process of the FDR (flight data recorder) data, clear similarities were noted by the investigation team between Ethiopian Airlines Flight 302 and Lion Air Flight 610, which will be the subject of further study during the investigation," the BEA said Monday.

CBS News correspondent Kris Van Cleave reported that satellite data also showed very similar flight patterns for the Ethiopian and Lion Air flights.

A jack screw, which helps to lower or raise the nose of the plane, was also recovered at both of the crash sites. When found, the screws were set in a position to put the plane into a dive.

French investigators downloaded all the data from the Ethiopian jet's black boxes over the weekend and handed it over to Ethiopian investigators who are running the probe into the crash.

The U.S. National Transportation Safety Board, the Federal Aviation Administration and Boeing are also part of the investigation.

In a statement, Boeing's CEO said the company was finalizing development of a software update, as well as a revision to pilot training, to address concerns stemming from the Lion Air crash late last year.

Congress plans to probe the FAA approval process for the new Boeing 737 Max, and CBS News has learned that at least one Boeing employee and an FAA staffer involved with the certification of the Max planes have been told to retain records pertaining to that approval process.

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 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.

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.

Meanwhile, Boeing's 737 Max 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.

Van Cleave said investigators still don't have enough information about the Ethiopian crash to say whether there are other issues that need to be addressed.