Freezing rain that caused United flight to slide off tarmac expected again Wednesday

Forty-five minutes of unexpected freezing rain at Spokane International Airport was blamed Tuesday for causing a loaded United Airlines jet to partially slide off a taxiway holding bay, forcing the airport to close for nearly three hours.

No injuries were reported among the 166 passengers and seven crewmembers aboard the United Airlines 737, which had been scheduled for departure to Denver at 5:38 a.m..

The mishap involving United Flight 812 occurred just before 6 a.m.

“It caught everybody by surprise,” said Larry Krauter, the CEO at the airport. Freezing rain had not been in the forecast, he said.

But the freezing rain was reported by the National Weather Service at its airport measuring station starting at 5:12 a.m.

An Alaska Airlines flight departed without incident at 5:15 a.m.

Krauter said an inbound Federal Express plane landed at 5:25 a.m. and the pilot reported good braking conditions.

After that, ground crews began applying de-icer, but had not yet reached the holding bay where the mishap occurred.

The United pilot recognized the developing slippery conditions and decided to wait for improved conditions in a holding bay at the southern end of Runway 3.

But the holding area, like other pavement, is graded to allow water to drain away. Krauter said the weight of the plane, its slow forward momentum and the slope of pavement grade all apparently contributed to the slide-off, with part of the plane ending up off the pavement.

Weather records show that a trace of freezing rain fell before 5:12 a.m., and then 0.02 inches of freezing rain accumulated before 6 a.m.

“Basically, the entire area got popsicled in 20 minutes,” Krauter said.

“The rapid onset of the freezing rain was obviously a very significant event,” Krauter said.

The airport reopened at 8:45 a.m. The United plane was left in place and had enough clearance for other aircraft to operate.

A Southwest Airlines flight from Boise that was due to land in Spokane around 7 a.m. was diverted back to Boise because of the closure, according to the airport’s website.

Airport workers helped United get the passengers off the plane in small groups, and they were taken back to the terminal on parking shuttles.

United dispatched to Spokane what Krauter called a rescue plane to get passengers to Denver. United spokeswoman Karen May said passengers were rebooked on that new Denver flight, which departed on time at 1:45 p.m.

The disabled airplane was left in place pending arrival of a United aircraft recovery crew, Krauter said. That team was expected to assess any damage and take steps to pull the plane back to the terminal area, where it would be inspected for air worthiness or potential repairs.

“The most important thing is nobody got hurt,” Krauter said. “It ended up being more of an inconvenience issue.”

He said airport officials have not detected any faults in their ground procedures for keeping runways ice-free.

The icy coating at the airport was also seen across the region, as a relatively weak but quick-moving weather system crossed the area. The accompanying freezing rain caused slippery roads and sidewalks early Tuesday, forecasters said.

Another round of snow, freezing rain and rain are expected early Wednesday, tapering off as the day wears on. A high of 36 is in the forecast.