Boeing's 737 Max shouldn't be allowed to fly with a controversial flight-control system, an aviation regulator reportedly said in leaked emails

• A manager at Canada's aviation regulator wrote in an email that Boeing's 737 Max should not be allowed to fly again with the controversial MCAS automated flight-control system, according to a New York Times report.
• In the leaked email, which was originally sent to officials at the FAA, as well as the European and Brazilian aviation regulators, the Canadian official said that he was worried that regulators might end up approving Boeing's fix to the system, even if issues continued to emerge.
• At least one manager at the FAA agreed, according to the Times.
• Sign up for Business Insider's transportation newsletter, Shifting Gears, to get more stories like this in your inbox.
• Visit Business Insider's homepage for more stories.

A manager at Canada's air safety regulator said that Boeing should remove an automated system, MCAS, from the 737 Max before the plane is allowed to fly again, according to a New York Times report.

The statement was reportedly made in e-mails to counterparts at the US Federal Aviation Administration, The European Union Aviation Safety Agency and Brazil's National Civil Aviation Agency, which were reviewed by the Times.

The 737 Max, the latest version of Boeing's best-selling plane, has been grounded since March after crashes in Indonesia and Ethiopia killed 346 people.

Investigations into the two crashes suggest that MCAS, or the Maneuvering Characteristics Augmentation System, erroneously engaged, forcing the planes' noses to point down, and that pilots were unable to regain control of the aircraft.

MCAS was designed to compensate for the 737 Max having larger engines than previous 737 generations. The larger engines could cause the plane's nose to tip upward, leading to a stall - in that situation, the system could automatically point the nose down to negate the effect of the engine size.

Boeing has been working at a furious pace to fix the MCAS software to prevent future accidental activations, and redesigning the plane's flight computer system, but there is still no clear indication of when the plane will return to service.

In the emails, Jim Marko, the manager in aircraft integration and safety assessment at Transport Canada Civil Aviation, wrote that the "only way I see moving forward at this point, is that MCAS has to go," the Times reported.

According to a different email reviewed by The Times, at least one FAA manager, Linh Le, shares his view.

Le, a system safety manager, reportedly forwarded Marko's e-mail to colleagues, and writing that Marko was concerned that "MCAS introduces catastrophic hazards that weren't there before," and that "it and the fix add too much complexity." Le reportedly also said that he had similar concerns.

In the email, Marko reportedly expressed concerns that regulators would feel pressured into accepting the updated software and certifying the Max to fly, even if issues with the fix continued to arise.

The email reportedly included a presentation into how Boeing could remove MCAS from the jet.

In a statement provided to Business Insider, Boeing said, "We continue to work with the F.A.A. and global regulators to provide them the information they are requesting to certify the Max for safe return to service."

The FAA, and Canadian, European, and Brazilian regulators did not immediately return Business Insider's requests for comment.

Are you an employee at Boeing, an aviation regulator, or an airline affected by the Boeing 737 Max grounding? Contact this reporter at dslotnick@businessinsider.com.

Get the latest Boeing stock price here.