[chris]

Alaska Airlines Flight 261 was a tragic aviation accident that occurred on January 31, 2000. The flight was a scheduled international passenger flight from Licenciado Gustavo Díaz Ordaz International Airport in Puerto Vallarta, Mexico, to Seattle-Tacoma International Airport in Washington, with an intermediate stop at San Francisco International Airport in California.

The aircraft, a McDonnell Douglas MD-83, experienced a catastrophic failure of its horizontal stabilizer trim system while over the Pacific Ocean. This failure resulted in the pilots losing control of the aircraft. Despite the crew's extensive efforts to regain control, Flight 261 entered a rapid, uncontrolled descent and eventually crashed into the Pacific Ocean off the coast of California.

All 88 people aboard the flight – 83 passengers and five crew members – tragically lost their lives in the accident. The crash prompted an extensive investigation by the National Transportation Safety Board (NTSB). The NTSB's final report concluded that the probable cause of the accident was 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 due to excessive wear resulting from Alaska Airlines' insufficient lubrication of the jackscrew assembly.

[Coreym07]

I believe this crash is what inspired the basis to the movie "Flight" with Denzel Washington

[BinLaughin69]

This isn't CVR (cockpit) audio, this is the ATC recording that's available already

[durt]

Originally Posted by Coreym07 ↗

I believe this crash is what inspired the basis to the movie "Flight" with Denzel Washington

No, that was cocaine and sex

[durt]

The company didn't lube the stabilizer jackscrew properly, and the threads failed. Plus, aggravating the situation, attempting to trouble shoot the problem during the flight, which resulted in a complete failure. The jackscrew is used to run the front of the stabilizer up and down, which controls the pitch trim of the aircraft.


"The National Transportation Safety Board determines that the probable cause of this accident was 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' insufficient lubrication of the jackscrew assembly."






https://www.ntsb.gov/investigations/...ts/AAR0201.pdf

[Clubhouse]

Mayday Aircrash Investigation...

https://www.dailymotion.com/video/x5cntpa

[eyeful_hound]

Originally Posted by Clubhouse ↗

Mayday Aircrash Investigation...

https://www.dailymotion.com/video/x5cntpa

Wow. That was profoundly sad. They were "screwed" from the beginning. I'm not sure if turning around right away would have had a successful landing. Although after "forcing" both motors to make it move - and it did - then they really were 100% doomed.

As far as design, I'm not sure what you even do for redundancy, you can't have two jack screws. The 2nd whatever can't be a horizontal "screw" it would almost have to be a free moving hydraulic, but once needed, how would you disengage the jack screw? Having a tougher nut at the end is no help either if the thing is free to move - air current would just flap it around randomly.

After thought: Pre take off, there should be a procedure to move that screw all the way each direction, and sensors to indicate position. How'd they take off with it pitched?

[Clubhouse]

I can't imagine how the cockpit crews of the two planes watching the events unfold must have felt.

[durt]

Originally Posted by eyeful_hound ↗

Wow. That was profoundly sad. They were "screwed" from the beginning. I'm not sure if turning around right away would have had a successful landing. Although after "forcing" both motors to make it move - and it did - then they really were 100% doomed.

As far as design, I'm not sure what you even do for redundancy, you can't have two jack screws. The 2nd whatever can't be a horizontal "screw" it would almost have to be a free moving hydraulic, but once needed, how would you disengage the jack screw? Having a tougher nut at the end is no help either if the thing is free to move - air current would just flap it around randomly.

After thought: Pre take off, there should be a procedure to move that screw all the way each direction, and sensors to indicate position. How'd they take off with it pitched?

The stab operation is checked, and it's positioned, applicably, for take off, depending on the weight and CofG of the aircraft.

It would be very difficult to prevent any failure if the proper maintenance procedures, and manufacturer's recommendations have been ignored, as they were in this case!

[William May]

I understand that one of the mechanics had written the jackscrew up during an inspection, and the managers decided it was still ok and didn't allow the discrepancy to be listed against the aircraft.