Allied Pilots Association's Dennis Tajer told CNBC on Thursday that Boeing CEO David Calhoun was too optimistic in his assessment of how pilots view the grounded 737 Max.
"We like what we're seeing so far but his exuberance over that is a little premature," said Tajer, spokesman for the APA, the labor union for American Airlines pilots. Capt. Tajer is also a pilot for American.
Tajer was responding to Calhoun's CNBC interview on Wednesday, when the aircraft maker's new CEO said that pilots, based on many test flights, like the 737 Max updates.
Boeing has been under intense scrutiny after two of its 737 Max jets crashed within five months of each other, killing a total of 346 people. Shortly after the second crash, involving an Ethiopian Airlines plane last March, the entire 737 Max fleet was grounded. The first crash was in October 2018, involving a 737 Max jet operated by Indonesia's Lion Air.
The automated flight-control system, known as MCAS, has been implicated in both crashes.
In their fatal dives, both pilots battled MCAS, which repeatedly pushed the nose of the planes down. It was erroneously activated by faulty sensor data.
"I don't want to answer the big question about how much pilots should fly or not on the basis of the MCAS experience and those instances," said Calhoun, a longtime Boeing board member and former Blackstone executive. "In those instances, we wish the MCAS was different and it didn't add to the complexity to that boundary condition that caused the problem."
Tajer said that automation isn't a "replacement" for pilot training. "The MCAS was poorly designed and it was the automation system that contributed to these crashes, that's the end of that."
Boeing has been working tirelessly to bring the Max back to the market and regain public and regulator confidence. It currently expects that regulators will permit the Max to return to service by the middle of 2020.
Calhoun on Wednesday said the updated 737 Max will be the safest jet in the air.
However, Tajer took issue with that, saying there should be no "incremental measure on whether an airplane is safer than one another."
"It's either safe or it isn't," he said. "We've seen the training modules for the simulator, and we appreciate them coming in quick. But we have a lot of questions on that as well."
Boeing on Wednesday reported its first annual loss since 1997 as it deals with increasing costs from the Max crisis. The embattled company posted a fourth-quarter loss of $2.33 per share on a revenue drop of 37% to $17.9 billion.
Boeing did not respond to a request for comment on Tajer's remarks.
— CNBC's Leslie Josephs contributed to this report.