The Federal Aviation Administration announced on Friday that all Boeing 737 Max 9 aircraft would remain grounded indefinitely.

It’s because of the midair blowout of a cabin panel, and new safety inspections would be performed.

The decision affects 171 jets. The FAA extended the grounding following a scary incident that occurred on January 5, in which a door plug on an Alaskan Airlines plane broke off mid-flight, forcing the aircraft to make an emergency landing in Oregon.

The FAA Administrator, Mike Whitaker, said that their priority is ensuring the safety of American travelers, and the Max 9s would not return to the skies until they were entirely satisfied that they were safe.

“We are working to make sure nothing like this happens again,” FAA Administrator Mike Whitaker told Fox Business.

“Our only concern is the safety of American travelers and the Boeing 737-9 Max will not return to the skies until we are entirely satisfied it is safe.”

The aviation regulator said that the grounding would be lifted after inspecting the planes.

On Friday, the FAA announced that 40 aircraft needed to be reinspected, and the results reviewed to determine whether the Max 9s were safe enough to fly again.