The head of the European Union Aviation Safety Agency (EASA) has said that it expects Boeing's grounded 737 MAX jets to return to service in January at the earliest.
EASA Executive Director Patrick Ky told Reuters: "As far as we know today, we have planned for our flight tests to take place in mid-December which means decisions on a return to service for January, on our side."
However, Ky declined to estimate when US regulators would make their own decision to lift the flight ban but says any gap between the agencies would be a matter of weeks rather than months.
The US Federal Aviation Administration has primary responsibility for lifting the ban and is expected to be followed by other regulators including the EASA, but news reports have speculated that other agencies could be slow to act.
"We may end up with a couple of weeks of time difference but we are not talking about six months," added Ky. "We are talking about a delay which, if it happens, will be due mostly to process or administrative technicalities."
Boeing has said it aims to return the jet to service by end-year following changes to cockpit software and training in the wake of two fatal crashes that sparked the grounding in March.