Atlanta - The failed computer system that caused flight delays across the country has been restored, the Federal Aviation Administration said Thursday.

FAA (web | news) spokesman Paul Takemoto said the system went out at 5:06 a.m. ET and came back on about five hours later. He said officials working to pinpoint the cause know that there was a problem with the main telecommunications systems.

"It was an efficiency problem rather than a safety problem, but it was a serious efficiency problem," Takemoto said.

Due to the outage, air traffic controllers had to enter flight plans manually, a problem that causes delays, according to the FAA and the National Air Traffic Controllers Association.

The air traffic controllers' group said the problem will cause flight delays throughout the day because of a "domino effect."

"Air traffic controllers are without electronic decision-making tools and cannot keep up with the sheer numbers of flights -- resulting in delays," the controllers' group said in a statement during the outage.

"Air traffic controllers on the ground at major airports are getting no automated flight plan information and have to enter that information manually, a cumbersome and time-consuming process."

Carmen McDonald was among those passengers inconvenienced by flight delays when the computerized system that airlines use to file flight plans failed for several hours Thursday in Atlanta, Georgia, and Salt Lake City, Utah.

McDonald said she thought her Spirit Airlines flight would leave on time around 7 a.m. ET from Fort Lauderdale, Florida. But the 39-year-old model sat for an hour and 15 minutes amid the noise of loud kids before the plane was ready to leave a logjammed runway and take off to Boston, Massachusetts.

"I'm frustrated," she said, distracted by using Twitter and calling on her cell phone as her plane sat planted on the runway. "I have somewhere to be."

(Courtesy: CNN)

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