United Airlines is conducting an internal investigation after one of its captains diverted a flight to deplane a senior flight attendant who he argued with.

Flight 842 from Sao Paulo, Brazil to Chicago O'Hare diverted to Miami early in the morning of 14 July midway through the scheduled 6hr 45min non-stop flight.

A source familiar with the incident says the captain ordered the purser of the Boeing 767 to leave the aircraft because he was "not respecting his authority".

The aircraft was on the ground for about an hour and arrived at Chicago just over an hour late.

A United spokeswoman says: "The pilot chose to divert the flight due to a crew issue"."

The captain felt the matter needed to be resolved on the ground, an FAA spokesman says. The aircraft landed without incident in Miami and was on the ground for less than hour before departing to Chicago, he adds.

Exact details of the incident have not been disclosed and United is investigating the matter to make sure that the decision to divert the aircraft was appropriate, the FAA spokesman says.

At the same time, FAA is investigating the incident to ensure that all diversion procedures were followed, he says.

Representatives for the Association of Flight Attendants (AFA-CWA) and the Air Line Pilots Association (ALPA) chapters representing United flight attendants and pilots declined to comment as they did not have details about the incident.

Source: Flight International