Boeing's grounded 737 Max airliner is likely to return to service in Europe during the first quarter of 2020, the head of the European Union Aviation Safety Agency (EASA) said on Monday. While the European regulator expects to give its approval in January, preparations by national authorities and airlines may delay the resumption of commercial flights by up to another two months, EASA executive director Patrick Ky indicated. "If there are training requirements (and) coordination to be done with the EU member states to make sure everyone does the same thing at the same time, this will take a bit of time," Ky said. "That's why I'm saying the first quarter of 2020." Boeing has said it aims to return the 737 Max to service by the end of 2019 after making software changes in the wake of two deadly crashes, which killed 346 people and led the U.S. Federal Aviation Administration (FAA) to ground the plane in March.

Aerial photo showing Boeing 737 Max airplanes parked at Boeing Field in Seattle, Washington, October 20, 2019. Gary He | Reuters

Besides damaging Boeing, the grounding has hit airline customers due to the hundreds of jets now stuck on the tarmac. Low-cost operator Ryanair, one of Boeing's biggest Max clients, said on Monday it expected further delays to Max deliveries to reduce its growth in 2020. The FAA has primary responsibility for vetting a Boeing-designed fix to avoid situations in which data from a single faulty airflow sensor can cause the flight software to send the plane into a dive. Instead, the so-called MCAS software will monitor data from a pair of the sensors. EASA also plans to carry out its own program of checks including simulator and flight tests, before allowing flights to resume in Europe.