PARIS/ADDIS ABABA (Reuters) – Investigators in France took possession of the crashed Ethiopian Airlines jet’s black boxes on Thursday, seeking clues into a disaster that has grounded Boeing’s global 737 MAX fleet and left scores of families mourning and angry.

Sunday’s crash after take-off from Addis Ababa killed 157 people from 35 nations in the second such calamity involving Boeing’s flagship new model in six months.

Possible links between the accidents have rocked the aviation industry, scared passengers worldwide, and left the world’s biggest planemaker scrambling to prove the safety of a money-spinning model intended to be the standard for decades.

Relatives of the dead stormed out of a meeting with Ethiopian Airlines on Thursday, decrying a lack of transparency, while others made the painful trip to the crash scene.

“I can’t find you! Where are you?” said one Ethiopian woman, draped in traditional white mourning shawl, as she held a framed portrait of her brother in the charred and debris-strewn field.

Nations around the world, including an initially reluctant United States, have suspended the 371 MAX models in operation, though airlines are largely coping by switching planes.

Another nearly 5,000 MAXs are on order, meaning the financial implications are huge for the industry.

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PARIS INVESTIGATION

After an apparent tussle over where the investigation should be held, the flight data and cockpit voice recorders arrived in Paris and were handed over to France’s Bureau of Enquiry and Analysis for Civil Aviation Safety (BEA) agency.

A BEA spokesman said he did not know what condition the black boxes were in. “First we will try to read the data,” he said, adding that the first analyses could take between half a day and several days.

The investigation has added urgency since the U.S. Federal Aviation Administration (FAA) on Wednesday grounded the 737 MAX aircraft citing satellite data and evidence from the scene indicating some similarities and “the possibility of a shared cause” with October’s crash in Indonesia that killed 189 people.

Though it maintains the planes are safe, Boeing has supported the FAA move. Its stock has fallen about 11 percent since the crash, wiping nearly $26 billion off its market value.

It is unclear how long the Boeing aircraft will be grounded.

A software fix for the 737 MAX that Boeing has been working on since the Lion Air crash in October in Indonesia will take months to complete, the FAA said on Wednesday.

Deliveries of Boeing’s best-selling jets have been effectively frozen, though production continues.

And in what may presage a raft of claims, Norwegian Air has said it will seek compensation from Boeing for costs and lost revenue after grounding its fleet of 737 MAX. Japan became the latest nation to suspend the 737 MAX planes on Thursday. And airline Garuda Indonesia said there was a possibility it would cancel its 20-strong order of 737 MAXs, depending on what the FAA does.

WHAT HAPPENED?

Under international rules, the Ethiopians are leading the investigation but France’s BEA will conduct black box analysis as an advisor. The U.S. National Transportation Safety Board (NTSB) will also have an influential role as representatives of the country where the Boeing plane was made.

The choice of the BEA followed what experts say appears to have been a tug-of-war between national agencies, with Germany initially invited to do the analysis.

Ethiopian Airlines criticised a French-backed investigation into a crash in Lebanon in 2010, when an Ethiopian plane crashed into the sea after take-off. It said the investigation was biased against the pilots, who were blamed for the crash.

There is a small pool of countries including Britain, France, the United States, Canada and Australia that are seen as leading investigators. But only France and the United States have the experience gleaned from being present at almost every crash involving an Airbus or Boeing respectively.

Since the Indonesia crash, there has been attention on an automated anti-stall system in the MAX model that dips the plane’s nose down.

The pilot of Flight 302 had reported internal control problems and received permission to return, before the plane came down and burst into a fireball on arid farmland.

Relatives are desperate to know what happened and to receive fragments if not corpses, given the fire and destruction at the site. They were at least able to vent their grief.

“We saw where he died and touched the earth,” said Sultan Al-Mutairi, who came from Riyadh to say goodbye to his brother Saad, who ran a recruitment agency in Kenya.