04:44 PM PST on Tuesday, February 21, 2006

By TERESA BELL, kgw.com Staff

An Alaska Airlines jet was forced to make an emergency landing in Portland Tuesday after oxygen masks deployed.

AP

An Alaska Airlines flight takes off in this file photo.

Alaska Airlines Flight 100 left Portland for Denver early in the morning and shortly after takeoff, the oxygen masks popped out, forcing the pilot to return to the Portland International Airport immediately. No one was injured.

This was the third emergency landing involving Alaska flights in the Northwest in just the last week. And the other two incidents were also quite similar.

In the first case, a flight originating in Seattle last Tuesday and headed to Denver had to return to SeaTac because the plane would not pressurize. Five people were injured in that incident, authorities said.

And then last weekend, an Alaska flight en route from Washington D.C. to Seattle had to make an emergency landing when the cabin failed to pressurize. No one was injured.

Airline officials said they are delving into the pressurization system to hopefully pinpoint the problem, but assured that they stand by their maintenance staff and procedures.

(KGW reporter Jack Penning also contributed to this article.)