The decision to look with “a criminal focus” at Boeing Co.’s conduct around the blowout of a door plug on a 737 Max 9 was taken too soon after the January accident, said Willie Walsh, director general of the International Air Transport Association. 

“I think it’s completely wrong,” Walsh said in an interview with Bloomberg in Hong Kong on Tuesday. He said that such moves aren’t in the interest of safety, the traveling public or the industry at large.

Air-safety regulators have worked for years with airlines, pilots and planemakers to encourage openness in investigating aircraft accidents. The use of self-reporting tools to spot and address errors has helped to drive down the number of accidents and deaths from air travel.

The probe “risks pushing people back into a period when we didn’t have as open a culture in terms of reporting,” the IATA head said. “To me, it’s a retrograde step, something that we have to push back and push back strongly against.”

The Justice Department has convened a grand jury as part of its ongoing criminal investigation into the Jan. 5 mid-air accident involving the near-new 737 Max operated by Alaska Airlines, Bloomberg News reported on Monday.

Bloomberg reported previously that the department was looking into whether the January incident falls under the government’s 2021 deferred-prosecution agreement with the company over two previous fatal crashes of its 737 Max jetliner. The panel blowout occurred just days before the expiration of the agreement’s three-year term. 

One concern over the criminal probe is that employees contacted by the Justice Department will hire lawyers and invoke their rights to avoid self-incrimination, slowing the work of safety regulators. 

Last week, US National Transportation Safety Board chair Jennifer Homendy told a Senate Commerce Committee panel that the DOJ probe raises concerns “when employees and others don’t feel safe to speak to us.”

Homendy, responding to questions from Senator Maria Cantwell, said anonymous reporting had “addressed risk proactively and encouraged employees to speak up.” 

Boeing reached the deferred prosecution agreement in January 2021, agreeing to pay $2.5 billion to settle a criminal charge that it defrauded the U.S. government by concealing information about the 737 Max, the ill-fated jet model involved in two fatal crashes in 2018 and 2019 that killed 346 people.

The crashes “exposed fraudulent and deceptive conduct by employees of one of the world’s leading commercial airplane manufacturers,” David Burns, acting assistant attorney general of the Justice Department’s Criminal Division, said at the time.

The deal, reached in the waning days of the Trump administration, was seen as lenient because it focused narrowly on the actions of two individuals and absolved senior management from “willingly facilitating” actions that led to a flawed flight-management system on the Max. Boeing had already reserved the bulk of the money for compensation to airlines, lessors and others affected by a worldwide ban on the model.