U.S. regulators will not likely give a green light to Boeing 737 Max airplanes to fly until 2020, the head of the Federal Aviation Administration (FAA) said Wednesday. 

“Like I said there are a number of processes, milestones, that have to be completed,” Steve Dickson told the CNBC network. “If you just do the math, it’s going to extend into 2020.”

Noting that there is no clear timeline for when the 737 Max will be re-certified, Dickson said that there are 10 to 11 milestones left to complete before it can be approved.

The return date of the troubled

Read more: US aviation chief red lights Boeing 737 Max until 2020