Boeing has refused to comment on reports that US pilots had voiced concerns over potential safety issues with 737 Max aircraft.

The American Airlines flight crew were secretly recorded in the wake of the Lion Air crash in Indonesia in October urging a software fix to the new aircraft.

However, this had not been introduced when an Ethiopian Airlines’ 737 Max crashed four months later, killing 187 people.

The Max remains grounded worldwide as Boeing updates the anti-stall system known as MCAS, although the manufacturer denies this was solely to blame for the accidents.

The audio of last November’s meeting was obtained by CBS and the New York Times and reported by the BBC yesterday.

Boeing vice-president Mike Sinnett told pilots: “No one has yet to conclude that the sole cause of this was this function on the airplane.” 

He reportedly added later in the meeting: “The worst thing that can ever happen is a tragedy like this, and the even worse thing would be another one.”

Pilots also complained they had not been told about MCAS, which was new to the 737 Max, until after the Lion Air crash off Indonesia, which killed 189. 

“These guys didn’t even know the damn system was on the airplane, nor did anybody else,” claimed Mike Michaelis, head of safety for the pilots’ union.

Boeing declined to comment on the November meeting, saying: “We are focused on working with pilots, airlines and global regulators to certify the updates on the Max and provide additional training and education to safely return the planes to flight.”

American Airlines said it was “confident that the impending software updates, along with the new training elements Boeing is developing for the Max, will lead to recertification of the aircraft soon.”

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