Atlanta (CNN Business) The spokesman for American Airlines' pilots union called Boeing's insinuation that foreign pilots were to blame for the crashes involving 737 MAX jets "inexcusable" and said AA pilots made several suggestions to Boeing to fix the 737 MAX's systems before the second plane crash.

In recent weeks, Boeing CEO Dennis Muilenburg and others have said that the actions of the pilots played a role in the chain of events that caused the crashes, which Dennis Tajer, spokesman for the Allied Pilots Association, said unfairly points the finger at foreign pilots.

"Shame on you... we're going to call you out on it," Tajer said of Boeing Thursday ahead of a Federal Aviation Administration meeting of international aviation regulators in Fort Worth, Texas. "That's a poisoned, diseased philosophy."

Tajer also told CNN American Airlines pilots made several suggestions on how to improve the safety of the Maneuvering Characteristics Augmentation System (MCAS) in a meeting with Boeing in November 2018, a few weeks after the October crash of Lion Air flight JT 610 in Indonesia and months before the Ethiopian Airlines crash in March.

When asked if the Ethiopian crash might have been prevented if Boeing had taken action on the pilots' suggestions, Tajer said, "I think that's a fair conclusion."

Boeing did not respond to CNN's request for comment.

Pilots could not overcome the MCAS

Tajer, who has flown the 737 MAX, argues the Ethiopian Airlines pilots did what they were instructed to do but that Boeing's MCAS forced the plane into such an aggressive downward angle that the pilots could not recover.

"They had wired that thing so that it was irrecoverable. It just blew us away," Tajer said.

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The MCAS software on the Boeing 737 MAX, which is designed to push the nose of aircraft down if it senses an imminent stall, is believed to have played a role in both the Lion Air and Ethiopian Airlines crashes that left a total of 346 people dead.

Muilenburg said in April that the safety systems on its 737 MAX jets were properly designed and the pilots did not "completely" follow the procedures that Boeing had outlined to prevent that kind of malfunction.

Ethiopian officials said the Ethiopian Airlines pilots repeatedly performed all of Boeing's procedures but could not recover the plane.

Recertifying the 737 MAX

Delegates from 33 international aviation authorities will meet with the FAA Thursday to discuss processes for reviewing the software fix Boeing has completed for the aircraft, which remains grounded worldwide.

Despite global scrutiny on the 737 MAX, FAA acting Administrator Dan Elwell on Wednesday rejected the notion that crashes involving the aircraft have shaken trust between foreign regulators and the FAA.

He said the FAA remains in "constant, close communication" with other regulators, and that although he expects the US to lift flight restrictions first, he expressed optimism foreign regulators would agree on processes to recertify the plane.

"Of course the idea is that globally we are working from the same sheet of music, and that sheet of music is the technical data and the processes that we're using to get the 737 MAX back" to flight, he said.

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The process has not been as fast as Boeing had initially projected. Elwell said the process was delayed by a review conducted by the manufacturer and questions from the FAA.

Elwell would not predict a timeline for certifying Boeing's software fix. When asked whether airline's plans to return the 737 MAX to service in August were realistic, he replied the he wouldn't even say October at this point because of the unknowns associated with the fix.

He said before recertification, the FAA must receive Boeing's final application and then conduct test flights, a system safety analysis and determine training requirements.

International regulators, including those in Canada and Europe, will conduct their own validations or independent design reviews of the aircraft's updated system before lifting flight restrictions.

A Boeing spokesperson said in a statement Wednesday the company has been working closely with the FAA and global regulators on processes to certify the updated MAX software and enhance pilot training.

"Safety is our shared priority and Boeing continues to fully support airline customers and regulators from around the world," the spokesperson said.