From the Aviation Safety Network:

On 31 January 2000 an Alaska Airlines McDonnell Douglas MD-83, registered N963AS departed Puerto Vallarta for a flight (261) to San Francisco. Control problems were reported by the crew and following a period of troubleshooting it was decided to divert to Los Angeles. Descending for LAX, control was lost and the flight crashed into the sea off the Californian coast, killing all 88 occupants.

The last radio transmission from the pilots of Alaska Airlines Flight 261 to air traffic controllers was a calm "thank you."

Then controllers heard only chilling reports from pilots of other planes who watched the Alaska jet make a horrifying, inverted dive into the Pacific Ocean from 17,900 feet.

"That plane has just started to do a huge plunge," the pilot of a corporate jet flying in the same area radioed controllers at 4:19:39 p.m., according to air traffic control tapes released yesterday.

Less than a minute later, he added: "Plane's inverted, sir."

That was followed by this transmission from the crew of a Sky West jet at 4:20:59 p.m.:

"He, ah, hit the water, he's down."

Read more...

• Aviation Safety Network: Accident Coverage: Alaska Flight 261.
• The Alaska 261 NTSB Findings and FAA Denial.
• Seattle Post-Intelligencer: Flight 261.