US plane maker Boeing, the world’s largest aviation company, is facing escalating pressure after Ethiopia said flight recorded data showed “clear similarities” between last week’s Ethiopian Airlines crash and that of Indonesia’s Lion Air five months earlier.

The Ethiopian Airlines crash on March 10 killed 157 people, leading to the grounding of Boeing’s 737 MAX fleet worldwide and sharpening focus on the safety of software installed on the planes.

Ethiopian Transport Ministry spokesman Muse Yiheyis said Saturday that an initial analysis of the plane’s black boxes in Paris showed “clear similarities” with a Lion Air crash in October, which killed 189 people.

Ethiopia is leading the investigation, though the black boxes were sent to France and US experts are also participating.

Both Ethiopian and Indonesia planes were MAX 8s and crashed minutes after take-off with pilots reporting flight control problems. Concern over the plane’s safety caused aviation authorities worldwide to ground the model.

Under scrutiny is a new automated system in the MAX model that guides the nose lower to avoid stalling.

US lawmakers and safety experts are asking how thoroughly US aviation regulators vetted the system and how well pilots around the world were trained for it when their airlines bought new planes.

With the prestige of one of America’ biggest exporters at stake, Boeing has said the 737 MAX series is safe, though it plans to roll out new software upgrades shortly.

After a 10 percent drop last week that wiped nearly $25 billion off its market share, Boeing stock slid another 3.5 percent on Monday to $365.60 in early pre-market trade.

Boeing has halted deliveries of its best-selling model, one intended to be the industry standard but now under a shadow.

There were more than 300 MAX airplanes in operation worldwide at the time of the Ethiopian crash, and nearly 5,000 more on order. The list price for each MAX plane is $121 million.

The Wall Street Journal reported on Sunday that the US Department of Transportation was scrutinizing the US Federal Aviation Administration (FAA) over its approval of the MAX series, while a federal jury had issued a subpoena to at least one person involved in its development.

The inquiry has huge financial implications and is crucial to give some closure to families of victims, who came from nearly three dozen countries.

Norwegian Airlines has already said it will seek compensation after grounding its MAX aircraft, and various companies are re-considering orders.

European plane maker Airbus, which is Boeing’s main rival, has seen its stock rise 5 percent since the crash, but cannot simply pick up the slack given the complicated logistics of plane-building.

One source close to the probe said Ethiopian officials had been reluctant to share information with US investigation teams and the plane maker. “There was a lot of distrust, especially at first, but it is easing,” the source said, asking not to be named.

The agony for families of the dead in Ethiopia has been compounded by their inability to bury remains. Charred fragments are all that remain and DNA testing may take months.

Presstv