In another setback to the beleaguered airline manufacturer, federal safety officials in the US are requiring inspections of cockpit seats on Boeing 787 Dreamliners after one of the jets went into a dive when the captain’s seat lurched forward without warning and disconnected the plane’s autopilot system.

Boeing also has stopped test flights of a new version of its 777 jetliner after discovering a damaged structural part between the engine and the rest of the plane. The new model has not yet been approved by regulators.

The Federal Aviation Administration said in an order published Wednesday that it will require operators of 787s to inspect both pilot seats for missing or cracked caps that cover a switch used to move the seats.

During a March flight by Chile-based Latam Airlines, the captain’s seat moved forward and hit a switch that disconnected the autopilot system. The plane, flying from Australia to New Zealand, rapidly dropped about 120 metres before the co-pilot regained control, according to a preliminary report by Chilean authorities. Several dozen passengers were injured, according to news reports.

Within days of the incident, Boeing recommended that airlines look at the cockpit seats on 787s for loose caps on the switches and told them how to turn off power to the motorized seats.

The FAA said it has received four other reports from Boeing of cockpit seats moving when not intended to, including one in June.

The FAA said its safety order will affect 158 planes registered in the United States.