Wiki...Return to Service:

International agreements allow for aviation regulatory agencies worldwide to certify an aircraft type based on the certification of the regulatory agency where the aircraft is built, and do not review those certifications in much detail. In this case the Boeing 737 MAX series is certified by the United States FAA, and a return to service locally and internationally requires updated certification by the FAA first. The European Aviation Safety Agency and Transport Canada announced they will do their own safety verifications before letting the 737 MAX fly again in their territories, and will no longer accept the United States FAA certification as is for this aircraft. Around March 20, 2019, Boeing announced it would make an additional safety feature on the plane model standard.

The FAA seeks consensus with other regulators to approve the return to service, to avoid suspicion of collusion with Boeing. On April 1, 2019, FAA said Boeing’s software fix for 737 MAX is still weeks away from delivery to FAA. This is an updated statement as Boeing previously told the public it is awaiting certification on the new software by the end of March.

On April 11, Boeing CEO Dennis Mullenburg said that the 737 MAX had completed 96 test flights with the new updated software. The software fix is expected to be delivered to the FAA "within the next two weeks."

For fleet scheduling and flight booking purposes, Southwest and American Airlines expect the 737 MAX to remain grounded (and flights canceled) through August 2019.


I wonder how the CAA will cope post-Brexit...should it happen.