Boeing holds test flights for 737 MAX fix: sources
https://phys.org/news/2019-03-boeing-flights-max-sources.html
Boeing needs authorization from the Federal Aviation Administration before the MAX can return to service. But the company still has not submitted its proposed software patch to the FAA, a government source told AFP.
The aircraft was grounded following two deadly accidents involving Ethiopian Airlines earlier this month and Lion Air in October which killed 346 people.