‘Billion-to-one shot’: How an RDU cleaning crew mishap left travelers powerless
The events that led to last week’s power outage at Raleigh-Durham International Airport were highly unlikely, the airport president says, but RDU is taking several steps to try to prevent them from happening again.
Terminal 2, the airport’s main terminal, lost power at about 1 a.m. Friday, Nov. 12, resulting in delayed and canceled flights throughout the day and forcing workers to process tickets, handle baggage and do security checks by hand.
The outage occurred after a member of a cleaning crew spilled water on the concourse floor. The water ran into the City Market News shop, which was closed at the time, and under a wooden podium holding magazines, candy and the cashier’s computer, says Michael Landguth, RDU’s president.
The wires to that computer came up through a small hole in the floor. When the water reached the hole, it drained down into an electrical switchgear box, tripping three large circuit breakers, Landguth said.
“Out of a million square feet, it was something the size of a silver dollar,” he said in an interview. “That was the point of where the failure occurred. And that has got to be a billion-to-one shot.”
It’s not clear how much water was spilled, Landguth said, though it could not have been more than the capacity of the 40-gallon trash can the cleaning crew was using to carry water. The can had been strapped to a cart, a practice the cleaning contractor has been told to stop.
The circuit breakers are part of one of the airport’s switchgears, which include a series of disconnect switches so power can be selectively cut off to different areas. The breakers are about the size of microwave ovens and had to be replaced.
“When we pulled the drawer out for a circuit breaker, water was pouring out of it,” Landguth said. “That is a bad thing.”
The hole in City Market News has since been plugged, Landguth said, and engineers are looking for other places where the electrical system might be vulnerable. The floors of all retail spaces in the terminals will now be tested for leaks, just as restaurant and food service spaces have been in the past.
“The team is going around and looking at the power feeds that are coming in and the switchgears to make sure there are no other holes above these things,” he said.
The terminal didn’t completely lose power, but several areas were affected. They included the passenger boarding bridges in Concourse C, ticketing counters, the Transportation Security Administration’s checkpoint and baggage screening equipment, baggage handling system controls and the heating and air conditioning system.
The affected switchgear is also used to handle power from the airport’s generator, so simply turning on the generator wasn’t an option, Landguth wrote in a report to the airport’s governing board.
Power wasn’t restored until 11:11 a.m. Most of that 10 hours was spent drying out the switchgear to make sure it was safe before re-energizing, Landguth wrote.
What else the airport is doing
The airport plans a series of other steps to fortify its electrical system:
▪ Check the airport’s inventory of spare electrical parts and make sure it has what it needs on hand. RDU had only two of the three backup circuit breakers it needed last Friday and had to bring in a third.
▪ Conduct an “arc flash study” to look for safety hazards in the airport’s electrical equipment.
▪ Review and update the operation of the airport’s circuit breakers to ensure they trip in the right order and as designed. They did in this case, but the airport wants to be sure that happens in the future.
▪ Do a more detailed analysis of what else RDU can do to prevent water from getting into switchgears and other electrical equipment.
Landguth said RDU’s biggest concern is for the switchgears themselves. The airport has replaced some in the past, and it took six weeks for new ones to arrive, even before the current supply chain snarls.
“You can only imagine what the time would have been now,” Landguth said. “If that had gone out, we would have been out of power for weeks.”
This story was originally published November 19, 2021 at 3:01 PM.
