An American airlines pilot was arrested Saturday on the runway as shocked passengers looked on after he failed a breathalyzer test at the Detroit Metropolitan Airport.

Flight 736, scheduled to leave Detroit about 7 a.m. en route to Philadelphia, was immediately canceled, according to ABC affiliate WXYZ.

A transportation security agent was the first person to spot the pilot acting suspiciously, the station reported. Minutes before the flight was to take off, airport police were called.

Michael Conway, director of public affairs at the Detroit Metropolitan Airport, told ABC News that the pilot failed an initial field breath test. After being arrested, he underwent a second test, which he also failed.

Conway told ABC that the pilot’s blood alcohol content was over the legal limit, but the precise measure was not released.

Conway added that the pilot — who has not been identified — is from Pennsylvania and was born in 1965, according to ABC News.

“This is a serious matter and we are assisting local law enforcement and the Federal Aviation Administration with the investigation,” American Airlines said in a statement. “We will handle this matter appropriately as the safety and care of our customers and employees is our highest priority.”

The incident and the confusion that followed was captured by some passengers who had to put their spring break plans on hold.

Amanda Albrecht, a teenage passenger who snapped a photo of the handcuffed pilot — which she tweeted using the hashtag #qualityhire — told WXYZ that she had not heard back from the airline.

“I honesty just couldn’t believe — I was speechless — that something like that could happen and, again, that he could get that close to the aircraft,” she told the station. “I kind of just wanted american Airlines to be like, ‘Hey, sorry, can we do something about it?'”

FAA rules state that “no person may operate or attempt to operate an aircraft” within eight hours of having consumed alcohol or “with a blood alcohol content of 0.04 percent or greater.” The agency recommends that pilots wait 24 hours from the last use of alcohol before flying.

“A hangover effect, produced by alcoholic beverages after the acute intoxication has worn off, may be just as dangerous as the intoxication itself,” an FAA safety brochure states. “Symptoms commonly associated with a hangover are headache, dizziness, dry mouth, stuffy nose, fatigue, upset stomach, irritability, impaired judgment and increased sensitivity to bright light.”

“A pilot with these symptoms would certainly not be fit to safely operate an aircraft,” the brochure adds.