The top US air transport regulator on Wednesday doused Boeing’s hopes that its 737 MAX will return to the skies this year while lawmakers probed why the agency did not ground the plane after the first of two crashes.

In an interview just ahead of a congressional hearing on the crashes, Federal Aviation Administration chief Steve Dickson told CNBC the aircraft will not be cleared to fly before 2020.

The process for approving the MAX’s return to the skies still has 10 or 11 milestones left to complete, including a certification flight and a public comment period on pilot training requirements, he said.

“If you just do the math, it’s going to extend into 2020,” he said. 

The MAX has been grounded since March following the second of two crashes that killed a total of 346 people.

Boeing has been aiming to win regulatory approval this month, with flights projected to resume in January.

But Dickson said, “I’ve made it very clear Boeing’s plan is not the FAA’s plan.” “We’re going to keep our heads down and support the team in getting this report done right.”

 Many of the questions at the subsequent hearing in the House Transportation Committee focused on why the FAA did not move more aggressively after the first crash.

Boeing and the FAA have been under intense scrutiny following the crashes for their response to issues with the aircraft, including the flight-handling system involved in both accidents, the Maneuvering Characteristics Augmentation System, or MCAS. Rather than grounding the plane after the October 2018 Lion Air crash, the FAA determined