The Federal Aviation Administration has launched an investigation into allegations that a flight crew for Atlantic Southeast Airlines - a Delta Airlines subsidiary - violated drinking and flying rules.
It is the second such case in a month; the earlier case involved America West.

FAA spokesman Christopher White said Atlantic Southeast Airlines is under investigation for "an alleged violation of alcohol-related regulations" at a Wilmington, N.C. airport on Sunday.

White declined to give details but said the investigation was focusing on ASA's Atlanta-bound Flight 4240, which had been scheduled to leave Wilmington at 6:15 a.m.

Airport Director John Rosborough says a crew member of Flight 4240 was stopped from boarding the plane at about 6 a.m., by a security officer with the Transportation and Security Agency. The agency conducts random alcohol testing of crew members, but authorities have not said whether those tests had anything to do with the decision to stop the crew member.

Delta spokeswoman Katie Connell said the flight was delayed nearly four hours over a "crew-related issue."

"ASA takes the allegations made by a security agent at Wilmington International Airport very seriously, and is conducting a full investigation," said Connell, who says the allegation was regarding "a first officer on that flight."

The flight had 28 passengers, who were removed from the plane at 6:40 a.m. and put onto other flights.

ASA, a Delta Connection carrier, operates eight 50-seat jets on daily flights between Atlanta and Wilmington.

On July 1, two America West pilots who were taxiing for takeoff from Miami were ordered to turn around and arrested for operating an aircraft under the influence of alcohol. A security screener had reported them.

Federal rules prohibit any member of a flight crew from consuming alcohol within eight hours of going on duty.

David Stempler, president of the Air Travelers' Association, a travel advocacy group, said, "This kind of event is very discouraging for airline passengers."