Operations at Atlantic Southeast Airlines, a Delta Connection regional carrier, returned to normal Thursday afternoon, a day and a half after it began canceling flights to inspect jet engines.
The airline canceled 277 flights starting late Tuesday, when it told the Federal Aviation Administration that it wasn't certain inspections of 87 engines on 60 regional jets had been done properly. It normally operates about 800 flights a day.
The planes involved were CRJ-200s made by Canada's Bombardier. They represented 54% of Atlantic Southeast's workhorse fleet of 112 CRJ-200s and about 40% of its total fleet of aircraft.
The airline hasn't yet calculated how many passengers' travel plans were disrupted.
However, the CRJ-200 has 50 seats, so the maximum number of passengers affected by the groundings was nearly 14,000. The actual number likely is closer to 8,500, though, because the disruption occurred during the slower midweek travel period when the carrier probably filled only about 60% of its seats.
In the fourth quarter of 2008, the most recent period for which data are available, the airline and its parent, SkyWest, based in St. George, Utah, filled an average of 77% of available seats, according to company records.
Kate Modolo, an Atlantic Southeast spokeswoman, said other Delta Connection carriers and, in some cases Delta itself, were able to accommodate passengers whose trips were disrupted.
The airline is the primary Delta Connection carrier at Delta's Atlanta hub. It serves 110 airports in 30 states, and in Canada and the Bahamas.
The airline ordered the groundings after discovering during a regular audit of maintenance records that 87 engines on the jets may have been operating beyond their inspection deadlines. The engines, made by General Electric, are to be inspected at least every 5,000 hours. On Wednesday, an FAA spokeswoman incorrectly told reporters that the time limit was 4,000 hours.
Modolo said the airline reported the situation to the FAA and grounded the planes, although some of the engines may have been properly checked, but the inspections weren't properly documented.