Investigation of the crash quickly focused issues surrounding the two-foot-long jackscrew -- part of a system that drives adjustments to the horizontal stabilizer, which in turn controls the pitch, or up-and-down orientation, of the aircraft. While in flight, the MD-83 experienced a sudden, sharp dive. It was suspected that there was a problem with the horizontal stabilizer "trim." After temporarily leveling out, pilots again lost control as they prepared the plane for an emergency landing at Los Angeles International Airport. After this change in "configuration," the plane entered an uncontrolled nosedive from 17,000 feet.
In December 2002, the National Transportation Safety Board attributed the crash to lack of grease on the jackscrew. Insufficient lubrication of the jackscrew led to the stripping of the screw threads, causing the plane’s horizontal stabilizer to jam in a position that forced the plane into a drastic nose-down orientation. The board blamed both the airline for its maintenance practices and the Federal Aviation Administration for its failure to adequately oversee the carrier. The board also concluded that a contributing factor was the lack of a fail-safe mechanism to protect the MD-80 from a catastrophic loss of the jackscrew.
The U.S. Attorney's Office for Northern California investigated claims of fraudulent record-keeping and cover-up at an Alaskan Airlines maintenance center in Oakland, where Flight 261 was last serviced before the crash, but announced in August 2003 that it would not file any criminal charges.
Meanwhile, the airline and The Boeing Company (which acquired the McDonnell Corporation Corp. in 1997) settled 87 of 88 wrongful death lawsuits stemming from the crash. Financial details were sealed from public view, but lawyers said the settlements were among the largest ever in an air disaster, in part because of the safety board’s strongly worded report assigning blame, and partly because of the nature of the crash itself. Relatives of the victims were granted the right to receive so-called pre-impact compensation, covering the emotional as well as the physical injuries the passengers encountered as the plane nose-dived into the ocean. Negotiators pointed out that the passengers experienced two separate freefalls, the first lasting 80 seconds and the final one lasting 90 seconds.
As of August 2004, only one of the suits, brought on behalf of passenger Joan Smith, 53, of Burlingame, California, remained pending.
Flight recorder data showed that Flight 261 crashed into the Pacific Ocean at 4:22 p.m., at a speed of more than 200 miles per hour.
Four years after the crash, a memorial (a sculpture of dolphins leaping around a sundial, financed by contributions from Alaska Airlines and from families and friends of the victims) was placed on the beach at Port Hueneme, California, opposite the spot where the plane went down 20 miles offshore.
Beginning in 2001, surviving family members of the Pearson, Barnett, and Clemetson families, as well as Queen Anne neighbors, began raising funds to renovate a nearby park, Soundview Terrace, to be an active memorial and to recognize the park's importance to their six children during their lifetimes. The park, located at 11th Avenue W and W Wheeler Street, opened on April 27, 2003, as Soundview Terrace/Rachel's Playground. The Pearson children's grandfather, Ralph Pearson, coined the name in honor of Rachel Pearson's near-daily visits to the tiny park during her brief lifetime.
Among the Washington residents killed on Flight 261 were:
- Stanford Poll, 59, Mercer Island, Washington, former owner of J&M Cafe and Blue Moon tavern in Seattle;
- Dr. David Clemetson, 40 (a Burien physician);
- Carolyn Clemetson, 31;
- Miles Clemetson, 6;
- Spencer Clemetson (infant son of Carolyn Clemetson);
- Coriander Barnett-Clemetson, 8;
- Blake Barnett-Clemetson, 6 (Cori and Blake were the daughters of Dr. Claire Barnett);
- Tom Stockley (wine columnist for The Seattle Times);
- Margaret Stockley;
- Rodney Pearson, 45 (vice president of operations for Six Degrees restaurants);
- Sarah Pearson (Alaska Airlines flight attendant);
- Rachel Pearson, 6;
- Grace Pearson (infant daughter of Sarah Pearson);
- Abigail Busche, 26;
- Ryan Busche, 28;
- Allison Shanks, 33 (Alaska Airlines flight attendant);
- Janice Stokes
- Craig Pulanco, (flight attendant who had changed his name from Craig Gruhl);
- Paul Pulanco, (a director of the Northwest AIDS Foundation);
- Meghann Hall, 19, Enumclaw;
- Ryan Sparks, 20, Enumclaw;
- Rachel Janosik (Horizon Air employee), 20, Enumclaw;
- Avinesh Amit Deo, 23;
- Avinash "A.V." Prasad, 19;
- Anjesh Prasad, 19 (Avinesh, Avinash, and Anjesh were cousins, all born in Fiji, who had gone to Mexico to celebrate Avinesh's graduation from ITT Technical Institute);
- Monte Lane Donaldson (a freelance DJ, engaged to marry Colleen Rose Whorley);
- Colleen Rose Whorley, (art director at Microsoft, engaged to marry Monte Donaldson);
- Don Shaw, 63 (retired elementary school principal in the Snohomish School District);
- Robert Thorgrimson, 63 (grandson of a founding partner in the Preston, Gates & Ellis law firm based in Seattle), Poulsbo, Washington;
- Lorna Thorgrimson, 53, (sold furniture at the Silverdale Bon Marche), Poulsbo, Washington;
- Deborah Penna (Cornish College art student);
- Michael Bernard;
- James Ryan (Alaska Airlines flight attendant), Redmond, Washington;
- Terry Ryan, Redmond Washington
- Barbara Ryan, Redmond, Washington;
- Bradford Ryan, Redmond, Washington;
- Russell Ing;
- Linda Knight, 51;
- Joe Knight, 54 (the Knights were co-pastors at The Rock Church in Monroe, Washington);
- Charlene Sipe;
- Harry Stasinos (insurance agent who lived with Charlene Sipe);
- Sherry Christiansen (Horizon Air Employee) Federal Way, Washington;
- Stacey Schuyler (Horizon Air Employee), Milton, Washington;
- Kristin Mills (Flight Attendant);
- Donald Shaw, Shelton, Washington;
- Larence Baldridge.