The machinists union added: "It is a certainty that flight attendants will have to de-escalate cabin situations due to hostility between passengers emanating from inflight voice calls. This is an avoidable distraction. Flight attendants already have the difficult and great responsibility of ensuring the safety and security of the flying public."
Delta pilot and president of the Air Line Pilots Association union Tim Canoll explained it from the cockpit's perspective during a briefing this week.
"We believe it is a degradation of safety to allow this," Canoll said. "We never know when the problem's going to come. It could happen just as you're backing off the gate. It could happen three hours into a 12-hour flight. There could be something that needs immediate attention."
"And therefore, there should be one venue where the flight attendant picks up the P.A. and she knows that's the only thing -- no one is competing for her attention," Canoll said. "If you notice the in-flight entertainment systems -- they freeze when the P.A. goes, because we need you to listen to that."
And the Association of Flight Attendants union made similar points in earlier comments, that allowing calls during flights could also "compromise a flight attendant's ability to maintain order in an emergency" and "interfere with crewmembers in the performance of their duties as first responders in the cabin."
What's more, the machinists union said it is concerned that terrorists "could use the new capability to communicate with each other in real time about the movement or vulnerability of crewmembers or to more easily launch a coordinated attack," the machinists union commented.
The Association of Flight Attendants also said it believes that allowing voice calls "in an environment where terrorists will be able to blend in with ordinary passengers... will inevitably increase safety and security risks."
Should voice calls be allowed on flights?