US aviation authorities have approved inspection and maintenance procedures for the Boeing 737-9 MAX jetliner to return to service.
The aircraft has been grounded since a window panel blew out on an Alaska Airlines flight over Oregon on January 5. A total of 171 planes around the world remain out of service.
The US Federal Aviation Administration on Wednesday announced the inspection and maintenance process, including detailed checks of bolts and other components.
It said, "Upon successful completion, the aircraft will be eligible to return to service."
FAA Administrator Mike Whitaker said, "The exhaustive, enhanced review our team completed after several weeks of information gathering gives me and the FAA confidence to proceed to the inspection and maintenance phase."
The FAA also said Boeing will not be allowed to expand production of the 737 MAX at this point.