Alaska Airlines Flight 261 Sundial

Alaska Airlines Flight 261, a McDonnell Douglas MD-83 aircraft, experienced a fatal accident on January 31, 2000 over the Pacific Ocean about 2.7 miles (4.3 km) north of Anacapa Island, California. The two pilots, three cabin crewmembers, and 83 passengers on board were killed and the aircraft was destroyed. Alaska 261 was a scheduled international passenger flight from Lic. Gustavo Díaz Ordaz International Airport in Puerto Vallarta, Mexico, to Seattle-Tacoma International Airport in Seattle, Washington, with an intermediate stop at San Francisco International Airport in San Francisco, California.

The subsequent investigation by the National Transportation Safety Board determined that inadequate maintenance led to excessive wear and catastrophic failure of a critical flight control system during flight. The probable cause was stated to be "a loss of airplane pitch control resulting from the in-flight failure of the horizontal stabilizer trim system jackscrew assembly's acme nut threads. The thread failure was caused by excessive wear resulting from Alaska Airlines's insufficient lubrication of the jackscrew assembly."