DETROIT (WWJ) – An American Airlines co-pilot accused of being drunk on the job at Detroit Metro Airport has been charged with a misdemeanor.

The Wayne County Prosecutor’s Office said the Pennsylvania man, identified as 50-year-old John Francis Maguire, on Monday was charged with one count of aircraft – operating under the influence.

An arraignment for Maguire, who was detained for a time and then released, was not immediately scheduled.

Police were alerted by TSA officers that Maguire was suspected of being under the influence of alcohol while in the cockpit of a plane preparing to take off early Saturday morning.

Airport officials said a field sobriety test was given, and he was taken into custody on the tarmac.

“Police responded with a field breathalyzer and the co-pilot was indeed over the legal limits,” Airport Public Affairs Director Michael Conway told WWJ. “They also took him to a local jurisdiction for a more sophisticated machine called the Data Master. On that machine, he also continued to be over the legal limit for a co-pilot.”

Conway did not offer any details as to what initially led TSA to suspect Maguire might be drunk, other than to say it was his behavior.

Flight-736 — which was scheduled to take off just before 7 a.m. for Philadelphia — was postponed and travelers were put on other flights.

An investigation by the Federal Aviation Administration is ongoing.