A new piece of evidence found by investigators on the ground here suggests the Ethiopian Airlines flight that crashed may have had a problem with a new flight-control system also suspected in the crash of a Lion Air flight in October.
It is the second piece of information suggesting similarities between the two crashes involving Boeing 737 Max 8 jets.
Investigators found a device known as a jackscrew in the wreckage. The jackscrew, used to set the trim that raises and lowers the plane’s nose, indicates the jet was configured to dive, according to John Cox, a former pilot and an airline-safety consultant with the Washington-based aviation-safety consulting firm Safety Operating Systems.
Meanwhile, French aviation experts began work Friday on the plane’s heavily damaged data and voice recorders.
In a preliminary investigation, the crash of a Lion Air Max 8 plane into the Java Sea on Oct. 29 was attributed to a faulty sensor causing an automated system to push the nose of the plane down. The possibility that the same scenario occurred in Ethiopia has prompted precautionary groundings of the plane all over the world. In all, more than 300 people have died in the two crashes involving the Max 8 jet.
Preliminary flight data showed the Ethiopian Airlines plane in trouble almost immediately and struggling to gain altitude in the high thin air above the Addis Ababa airport. The plane descended and then sharply ascended while moving at speeds far in excess of normal.
Cox, formerly the top safety official for the Air Line Pilots Association, said he was privately briefed on the evidence Thursday by people familiar with the investigation.
“All we can say definitely is that the trim was in a position similar to the position found on the Lion Air airplane and it would cause the nose to go down,” he said. “This will be consistent with a nose-down flight path, which they think is likely with the Ethiopian airplane.
“It points to one central link,” Cox said. “We need the data from the flight data recorders. We need it as quickly as possible. . . . The faster that we get that information, it will let everyone know what needs to be done. We don’t know in fact if these accidents are related. There are some similarities.”