About 150 United Airlines flights were grounded Tuesday morning because of an automation issue, a Federal Aviation Administration advisory says.

United spokesman Charles Hobart said the temporary delays began at about 8 a.m. Central time and lasted until roughly 8:40 a.m.. The ground stop affected roughly eight percent of the airline’s morning schedule, he said.

The Chicago-based airline offered few details about the nature of the problem. The FAA referred all calls to United.

An e-mail sent by the airline Tuesday morning said: “United began delaying flights at approximately 8 a.m. [Central time] to ensure aircraft departed with proper dispatching information.”