Last month, the company ousted its chief executive and chose to temporarily halt production of the plane in mid-January.
Boeing 737 Max jets in airline fleets around the world have been grounded since March, following the second crash of the airplane in less than six months.
Calhoun, a longtime Boeing board member, officially took over on Monday as chief executive, replacing Dennis Muilenburg, who was ousted in December as the company faces a drawn-out crisis following deadly crashes of a top-selling jet. The incidents have already cost the company more than $9 billion and led to the suspension of production of the 737 MAX due to lengthy delays in winning regulatory approval to resume flights. Calhoun also served as chief executive at data analytics company Nielsen and as a senior executive at the Blackstone Group.
But others have noted that Calhoun has hands-on experience in industrial leadership, having overseen a General Electric division that oversaw aircraft engines, rail, among other units.
"I want to stress the importance of holding firm that there will not be any type of simulator training required to transition from NG to MAX". Boeing also stated that it would be "taking appropriate action" in response to the content of the messages including "disciplinary or other personnel action, once the necessary reviews are completed".
Boeing said the communications "do not reflect the company we are and need to be, and they are completely unacceptable".
The messages underscore how important to Boeing financially it was to avoid simulator training for the Max. Calhoun said in his Monday email the company "will foster an inclusive environment that embraces oversight and accountability and puts safety, quality and integrity above all else".
U.S. Representative Peter DeFazio, who chairs the House Transportation and Infrastructure Committee, told reporters on Friday he advised Calhoun in a conversation he needs "to do something to relieve the pressure from Wall Street on your organization, which ultimately drove all this". Tom Gentile, Spirit AeroSystems president and CEO said in a statement. He argues "Boeing needs a CEO with an understanding of aviation markets, program management, and most of all, engineering".
Calhoun said he will spend his first weeks as CEO listening to employees, customers and regulators and assuring them Boeing is on the way to meeting their expectations.
On Friday, the board approved a $1.4 million annual salary for Calhoun and long-term compensation of $26.5 million if he achieves several milestones, including the return to service of the 737 Max.