(Reuters) – Democratic Senators Richard Blumenthal and Ed Markey called on the Federal Aviation Administration (FAA) to make public all data and information used to justify the Boeing BA.N MAX’s return to service and disclose any internal objections raised by FAA employees.

The FAA has proposed requiring a series of software upgrades and other changes before the 737 MAX could return to service. The airplane has been grounded since March 2019 after two fatal crashes in five months killed 346 people.

“Robust transparency is needed to ensure that independent experts and the public can review whether this aircraft is truly safe before it takes to the skies again,” the senators wrote. Boeing and the FAA did not immediately comment.

SOURCE REUTERS