No one was hurt during an evening Horizon Air flight Dec. 29 that landed on a taxiway that is 60 percent the width of the runway when the runway lights failed at Pullman-Moscow Regional Airport.

The Pullman airport confirmed the incident occurred on the 6:24 p.m. arrival from Seattle after the Lewiston Tribune learned about it Monday.

"At the time, we were trying to figure out what happened," airport Executive Director Tony Bean said. "It was over the holidays."

About 3 miles from the airport, the crew positioned the aircraft for landing and attempted to activate the remote-controlled runway lights, said Horizon Air spokesman Ray Lane in an email.

"The crew having not been informed of the non-operational runway lights, misidentified (the taxiway as the runway), lined up to it and safely landed," Lane said.

The taxiway and runway are both the same length - 6,730 feet - but are different in a number ways, Bean said. The taxiway is 60 feet wide and the runway is 100 feet wide. The taxiway has solid blue lights and yellow markings, while the runway has red, amber and white edge lights and white markings.

The 38 passengers on the 76-seat Bombardier Q400 aircraft, which wasn't damaged, were not informed about what happened in the otherwise an uneventful landing by a captain with 17 years of experience, Lane said.

"The pilots have been temporarily removed from flight status while the landing is being investigated," he added.

The Federal Aviation Administration confirmed it is looking into the incident, and didn't state when its investigation would be complete.

The airport spent $500 to $600 to repair the lights in the aftermath so it could resume regular operations, Bean said.

Planes can't use the runway at night without lights. Normally, Horizon would have landed an incoming flight from Seattle at about midnight and that plane would have returned to Seattle early Dec. 30, Bean said.

Regular service resumed mid-day Dec. 30 with the arrival of an inbound Seattle flight, Bean said, and an electric short caused by flooding was responsible for the problem.

Earlier Dec. 29, heavy snow and rain flooded certain parts of the airport like the general aviation ramp, prompting the airport to put out a notice to pilots, Bean said.

Later, as the weather worsened, one of the vaults that houses wires for the runway lights flooded, shorting an electrical cable that was already compromised because of damage to a protective covering, Bean said.

The change in conditions happened quickly, Bean said, and when a private plane landed about two hours before the Seattle flight, the runway lights were fine.

Typically the runway lights aren't checked before the Seattle evening flight because it isn't dark enough to see if all the features of the runway lighting are working, Bean said.

The airport has since inspected its other vaults to be sure all equipment is operating correctly and is reviewing the incident to see if it should make any changes to prevent something like this in the future.

While the cable that failed is inspected regularly, the issue would have been hard to see with an unaided human eye, Bean said, and one of the possibilities could be adding technology that can spot those types of problems used at larger airports.

Unlike the Lewiston-Nez Perce County Regional Airport, the Pullman airport has no staffed air-traffic control tower, which also could have prevented the incident, Bean said.

"If someone had been in the tower, the airplane likely wouldn't have been cleared for approach."

The Dec. 29 incident is one of the reasons for the $119-million upgrade underway at the Pullman airport. The runway and taxiway right now are in a flood plain.

As part of the lengthening and re-alignment that will be done in 2020, Airport Creek is being diverted into pipes to reduce the possibility of flooding, Bean said.

---

Williams may be contacted at ewilliam@lmtribune.com or (208) 848-2261.

Recommended for you