Updated: April 12, 2013 12:10PM
Officials at O’Hare International Airport continue on Friday to investigate a power outage that affected the lights on four runways Thursday night.
“Currently all airfield lighting is operational” and all airport operations were running normally, city Department of Aviation spokesman Gregg Cunningham said Friday morning.
For about 40 minutes Thursday night, flights were affected when four runways were closed after a power outage darkened them.
The lights went out about 9:20 p.m. on the four runways, all on the north airfield, Department of Aviation spokeswoman Karen Pride said. The problem was resolved by 10 p.m.
The exact number of flights delayed by the power outage was not immediately available following the outage, Pride said.
The affected runways are primarily arrival runways, Pride said.
Flights were also affected Thursday due to low visibility, according to the Department of Aviation. As of 8:30 p.m., more than 180 flights were canceled at O’Hare and flights at Midway were delayed up to 30 minutes.