Defense attorney Frank Walker II confirmed Ray Howland, 55, of Arlington, Texas, will plead guilty Wednesday afternoon.
Howland was arrested near Pittsburgh International Airport last June by an undercover state attorney general's agent who posed as a woman with a 10-year-old daughter.
Howland used an iPad and cellphone to send explicit messages after posting online that he was "looking for a family or a couple of girls" for sex while in town on business, prosecutors said.
"A lot of times in these cases you see double that amount," Walker said of the 10-year sentence. "It's hard to say someone can be satisfied, but they will be accepting of a 10-year sentence. When they're facing 19, 20 years, it seems like a reasonable resolution."
More From This Section
"He and his wife have undergone counseling. He's undergone counseling," Walker said. "He's looking forward to paying his debt to society and putting this behind him." State authorities had filed other charges against Howland, including attempted child rape, but they were withdrawn after federal authorities took over the case.
The plane was the first of two that crashed into New York's World Trade Center towers.
Howland was a supervisor at American's system operations control center. Transcripts show he told other American employees not to disclose the hijacking minutes before the Boeing 767 hit the World Trade Center.
"We don't want this getting out," Howland said, according to the transcripts. "We're aware of the situation. We're dealing with it right now. So let us deal with it."