Boeing's troubled 737 MAX airliner, grounded for 18 months after two deadly accidents, could receive certification to fly again in Europe "by the end of the year", the EU's air safety chief said Friday.

Months after the crash of a Lion Air 737 MAX in Indonesia that killed 189 people, a second disaster involving an Ethiopian Airlines plane in which 157 died prompted flight bans around the world for the model.

Now "for the first time in a year and a half, I can see we're in sight of the end of the work on the MAX," European Aviation Safety Agency (EASA) chief Patrick Ky told reporters in a video press conference.

"We're starting to look at how we can get the MAX back in service by the end of the year".

Early September certification flights by EASA followed June testing by the US Federal Aviation Administration (FAA) in June.

But the aircraft must still overcome several hurdles, including in pilot training, before authorities give their green light.

Even with "just about simultaneous" permission from the EASA and FAA, it will be up to individual nations and airlines to give the go-ahead for 737 MAX flights to resume, Ky said.

A US Congressional report published earlier this month called the earlier crashes "the horrific culmination of a series of faulty technical assumptions by Boeing's engineers, a lack of transparency on the part of Boeing's management, and grossly insufficient oversight by the FAA."