US Aviation Regulator Probe System Outage After Huge Disruption 

Aviation authorities are trying to figure out what caused the outage of a crucial alert system that forced the temporary halt on all US domestic takeoffs, triggering thousands of delays and cancellations. <br />The US Federal Aviation Administration says normal operations were being restored but the early morning halt created knock-on effects that snarled travel throughout the day. <br />The grounding order was issued after the FAA identified an issue with the Notice to Air Missions system which provides information to pilots about hazards, changes to airport facilities, and information that can affect flights. <br />Wednesday’s nationwide order was believed to be the first time since the attacks of 9/11 that such a broad command had been issued, according to aviation experts cited in US media.