May 29 (UPI) -- It could be another three months before Boeing's 737 Max fleet is cleared to return to the skies, the industry's top trade association said Wednesday.
International Air Transport Association Director-General Alexandre de Juniac said at a conference in South Korea it's planning the planes to remain grounded for another three months.
The IATA represents 290 airlines, or more than 80 percent of total air traffic.
"We do not expect something before 10 to 12 weeks in re-entry into service," de Juniac said. "But it is not our hands. That is in the hands of regulators."
"The regulators aren't on the same page," De Juniac added. "Otherwise, they'd have a similar timeline, a similar set of measures."
Boeing's Max 8 and Max 9 fleets were grounded worldwide in March following two deadly crashes in Indonesia and Ethiopia. Investigators have said they've found "clear similarities" between them that involve the model's automated flight system.
Investigators believe both planes were fed faulty data from a sensor. Boeing is working with the Federal Aviation Administration on a software solution. The FAA has not yet committed to a date when the aircraft can return to service.
European regulators have said they will scrutinize the entire flight control system before allowing it to service.
Acting FAA chief Dan Elwell said last week the United States will be the first to clear the 737 Max planes to return to flight.
"The 737 Max will fly again when we have gone through all of the necessary analysis to determine that it is safe to do so," he said.
"If it takes a year to find everything we need to give us the confidence to lift the order, then so be it."