WASHINGTON, June 13 (Reuters) - The Federal Aviation Administration and European Union Aviation Safety Agency said on Thursday they would boost collaboration on new airplane certification following a three-day joint meeting in Washington.

Since two Boeing 737 MAX crashes in 2018 and 2019 that killed a combined 346 people, aviation regulators around the world have tightened oversight of new airplanes.

The FAA and EASA pledged to take a number of steps to work together more closely and deepen proactive collaboration on certification activities.

"As we look to the next decade, establishing a unified strategic direction based on information sharing and collaboration with our international partners will meet the needs of our global aviation system of the future," FAA Administrator Mike Whitaker said in a statement.

EASA Executive Director Florian Guillermet said it was more important than ever for international aviation regulators to work together and to ensure that safety needs were always met.

Guillermet told Reuters last week he would propose the FAA act as an observer on safety audits, including those of European planemaker Airbus.

The EASA and FAA also vowed to strengthen information exchanges on safety oversight and to encourage each agency's technical experts to "work together and rely on one another to reduce duplication of effort, taking a risk-based approach."

The FAA is closely scrutinizing two new variants of the MAX awaiting certification, including the MAX 7, which is not expected to be certified until 2025 at the earliest after Boeing dropped a request in January for a key safety exemption.

Boeing is also seeking certification of the 777X, a more fuel-efficient version of its popular 777 widebody. EASA has sought changes in flight controls of the 777X.

The FAA in November adopted a new aircraft certification policy requiring key flight control design changes to be considered "major" like the anti-stall system involved in the two fatal MAX crashes.

Boeing did not disclose key details to the FAA of the safety system called MCAS, which was linked to both fatal crashes and designed to help counter a tendency of the MAX to pitch up in certain flight conditions. (Reporting by David Shepardson; Editing by Jamie Freed)