June 29 (UPI) -- The Federal Aviation Administration started test flights of the Boeing 737 Max on Monday morning, moving the once best-selling aircraft one step closer to recertification after being grounded for more than a year after two crashes in six months overseas.
The certification flights, which started out of Seattle, will continue for the next three days as Boeing hopes to demonstrate software problems blamed for the crashes in Indonesia and Ethiopia have been resolved.
"The FAA is following a deliberate process and will take the time it needs to thoroughly review Boeing's work," the FAA said in a statement about the flights being done with test pilots and engineers.
"We will lift the grounding order only after we are satisfied that the aircraft meets certification standards."
The test flights are only part of the final steps for recertification, and the 737 Max might not be back in the air until late fall. The aircraft also must pass an international evaluation of minimum pilot training requirements, the agency said.
The FAA told Congress on Sunday it cleared Boeing to continue testing of the troubled 737 Max, which has been under scrutiny for more than a year after faulty software was blamed for two crashes with six months of each other.
The FAA confirmed it would allow continued testing in an email to staffers in Congress.
"Over the past several weeks the FAA has been reviewing the system safety assessment submitted by Boeing," the FAA said in the communication. "The FAA's Type Inspection Authorization Board has completed its review, clearing the way for flight certification testing to begin."
The 737 Max has not flown since mid-2019 after the two flights in Indonesia and Ethiopia killed 346 people. Since then Boeing has struggled to correct old software problems and a new one that cropped up, keeping the plane grounded. The problems have cost Boeing $18.7 billion.
"Boeing continues to work diligently to support the safe return of the 737 Max to commercial service," the company said in a statement. "We defer to the FAA and global regulators on the process."