FILE PHOTO: Unpainted Boeing 737 MAX aircraft are seen parked in an aerial photo at Renton Municipal Airport near the Boeing Renton facility in Renton, Washington, U.S. July 1, 2019. REUTERS/Lindsey Wasson/File Photo

CHICAGO (Reuters) - The U.S. Federal Aviation Administration said on Thursday it has invited a cross-section of line pilots from global carriers that operate Boeing Co’s 737 MAX to participate in simulator testing as part of an overall testing and validation process of new MAX procedures.

In a statement, the agency said it has not specified a firm schedule for the tests nor the number of required hours of flight experience beyond asking that the crew have previous experience at the controls of the Boeing 737 MAX.

The MAX was grounded worldwide in March following two fatal crashes.