Grave 'aide memoire' from a Cockpit Voice Recording (CVR) transcript


Don Palmer

On a routine basis, I remind myself in a most serious way, why I must hold fast to O.E.M., regulatory and standard(s) compliance and processes. The Cockpit Voice Recording (CVR) transcript that follows is a grave ‘aide memoire’.

Januany 31 2000
Off Point Mugu, California
Alaska Airlines, Flight 261
McDonnell Douglas MD-83

The aircraft crashed into the Pacific Ocean south of Point Mugu in 650 ft. feet of water while en route from Puerto Vallarta to San Francisco. Radio transmissions from the plane indicated the pilots were struggling with a jammed stabilizer for the last 11 minutes of the flight before nose-diving into the ocean. While preparing to make an emergency landing in Los Angeles International Airport control was lost and the MD-83 was seen in a nose down attitude, spinning and tumbling in a continuous roll, inverted before it impacted the ocean. All 88 aboard were killed. The probable cause was loss of airplane pitch control resulting from in-flight failure of the horizontal stabilizer trim system jackscrew assembly's acme nut threads due to insufficient lubrication of the jackscrew assembly.

RT = Radio Transmission
CAPT = Captain
F/O = First Officer
FA = Flight Attendant
ME = Mechanic on the ground at LAX
LA14 = LA ARTCC Sector 14
LA25 = LA ARTCC Sector 25
LA30 = LA ARTCC Sector 30

16:08:03 RT CAPT: Yea we tried everything together.

16:08:08 RT CAPT: We've run just about everything if you've got any hidden circuit breakers we'd love to know about 'em.

16:08:35 RT CAPT: It appears to be jammed, the whole thing, it spikes out when we use the primary, we get AC load that tells me the motor's tryin' to run but the brake won't move it, when we use the alternate, nothing happens.

16:08:50 ME You say you get a spike on the meter up there in the cockpit when you uh try to move it with the primary right?

16:08:59 CAPT: I'm gonna click it off you got it?

16:09:00 F/O: Ok.

16:09:01 RT CAPT: When we do the primary trim, but there's no appreciable uh change in the uh electrical uh when we do the alternate.

16:09:13 CAPT: Let's do that.

16:09:14 [Sound of click]

16:09:14 CAPT: This'll click it off.

16:09:16 [Sound of autopilot disengaging] [Sound similar to horizontal stabilizer in motion tone]

16:09:16 CAPT: You got it?

16:09:26 CAPT: It got worse.

16:09:31 CAPT: You're stalled.

16:09:32 [Sound of air frame vibration]

16:09:33 CAPT: No no you gotta release it ya gotta release it.

16:09:34 [Sound of click]

16:09:52 CAPT: Help me back help me back.

16:09:54 F/O: Ok.

16:09:55 RT CAPT: Center Alaska two sixty one we are uh in a dive here.

16:10:01 RT CAPT: ... and I've lost control, vertical pitch.

16:10:01 [Sound of overspeed warning] (continues for 33 seconds)

16:10:05 LA30: Alaska two sixty one uh say again sir.

16:10:06 RT CAPT: Yea we're out of twenty six thousand feet, we are in a vertical dive...not a dive yet... but uh we've lost vertical control of our airplane.

16:10:10 LA30: Alaska two sixty one roger.

16:10:20 CAPT: Just help me.

16:10:28 RT CAPT: We're at twenty three seven, request uh...

16:10:33 RT CAPT: Yea we got it back under control here.

16:09:34 RT F/O: No we don't!

16:10:36 LA30: Alaska two sixty one uh say the altitude you'd like to uh remain at

16:10:45 F/O: Let's take the speed brakes off.

16:11:03 LA30: Alaska two sixty one say your condition

16:11:07 RT CAPT: Two sixty on, we're at twenty four thousand feet, kinda stabilized.

16:10:55 CAPT: Ok it really wants to pitch down.

16:10:58 RT CAPT: We're slowin' here and uh, we're gonna uh do a little troubleshooting, can you gimme a block between un, twenty and twenty five?

16:11:21 LA30:: Alaska two sixty one maintain block altitude flight level two zero zero through flight level two five zero

16:11:26 RT CAPT: Alaska two sixty one we'll take that block we'll be monitoring the frequency.

16:11:43 F/O: Whatever we did is no good, don't do that again.

16:11:44 CAPT: No it went down it went to full nose down.

16:11:48 F/O: Un it's a lot worse than it was?

16:11:50 CAPT: Yea yea we're in much worse shape now.

16:11:59 CAPT: I think it's at the stop, full stop...and I'm thinking...can it go any worse...but it probably can...but when we slowed down, let's slow it let's get down to two hundred knots and see what happens.

16:12:33 RT CAPT: We did both the pickle switch and the suitcase handles and it ran away full nose trim down.

16:12:42 RT CAPT: And now we're in a pinch so we're holding uh we're worse than we were.

16:13:04 RT CAPT: (Transmission indicated he was reluctant to to try troubleshooting the trim system again because the trim might go in the other direction)

16:13:22 RT CAPT: I went tab down... right, and it should have come back instead it went the other way.

16:13:32 CAPT: You wanna try it or not?

16:13:35 F/O: Uhh no. boy I don't know.

16:14:03 LA30: Alaska two sixty one uh let me know if you need anything.

16:14:07 RT CAPT: We're still working at it.

16:14:09 LA30: Roger.

16:14:54 LA30: Alaska two sixty one contact LA center one two six point five two they're aware of your uh situation.

16:14:59 RT CAPT: Alaska two sixty one say again the frequency one two zero five two.

16:15:03 LA30: Uh Alaska two sixty one twenty six fifty two.

16:15:06 RT CAPT: Thank you.

16:15:19 RT CAPT: LA Alaska two sixty one uh we're with you at twenty two five we have a jammed stabilizer and ah we're maintaining altitude with difficulty uh but uh we can maintain altitude we think and our intention is to land at Los Angeles.

16:15:35 LA25: Alaska two sixty one Alaska Center roger uh you're cleared to Los Angeles Airport via present position uh direct Santa Monica direct Los Angeles and uh you want lower now or what do you wanna do sir.

16:15:56 RT CAPT: Center Alaska two sixty one I need to uh get down about ten change my configuration make sure I can control the jet and I'd like to do that out there over the bay if I may.

16:16:06 LA25: Ok Alaska two sixty one roger that stand by there.

16:16:10 LA14: That's fine go ahead green light

16:16:11 LA25: Hey Alaska two sixty one wants to go into LA.

16:16:14 LA14: No problem

16:16:15 LA25: He wants to get down to around ten thousand feet but he wants to do it out there over the bay.

16:16:17 LA14: Sure.

16:16:19 LA14: Ok.

16:16:19 LA25: I'm gonna send him out on like a two eighty heading right now and then uh.

16:16:22 LA14: Ok put him on a...

16:16:23 LA25: He's at two two five right now.

16:16:25 LA14: Uhhh Ok that's fine.

16:16:25 LA25: Altitude altitude.

16:16:27 LA14: Put him on a two eighty heading take him down to one seven thousand radar contact.

16:16:29 LA25: He're we go.

16:16:30 LA14: (unintelligible)

16:16:31 LA25: Alaska two sixty one uh fly heading of two eight zero and descend and maintain one seven thousand.

16:16:39 RT CAPT: Two eight zero and one seven seventeen thousand Alaska two sixty one and we generally need a block altitude.

16:16:44 LA25: Ok uh just um I'll tell you what uh do that for now sir and contact LA Center on three five point five they'll have further uh instructions for you sir.

16:16:56 RT CAPT: K thirty five five say the altimeter setting.

16:16:59 LA25: The LA altimeter is three zero one eight.

16:17:01 RT F/O: Thank you.

16:17:02 LA25: Thank you.
[This was the last radio transmission from the aircraft]

16:17:04 CAPT: I need everything picked up... everything strapped down. I'm gonna unload the airplane and see if we can ....we can regain control of it that way.

16:17:09 FA: Ok we had like a big bank back there.

16:17:11 CAPT: Yea I heard it.

16:17:15 CAPT: I think the stab trim thing is broken.

16:17:21 CAPT: Make sure the passengers are strapped in now.

16:17:24 CAPT: Cause I'm gonna I'm going to release the back pressure and see if I can get it... back.

16:17:54 CAPT: Gimme slats extend.

16:17:56 {Sound similar to slat/flap handle movement]

16:17:58 CAPT: I'm test flying now.

16:18:05 CAPT: Flaps 11 degrees.

16:18:07 [Sound similar to slat/flap handle movement]

16:18:17 CAPT:: It's pretty stable right now...see but we got to get down to a hundred an eighty.

16:18:26 CAPT: Ok... bring the flaps and slats back up for me.

16:18:37 [Sound similar to slat/flap handle movement]

16:18:47 CAPT: What I wanna get the nose up...and then let the nose fall through and see if we can stab it when it's unloaded.

16:18:56 F/O: You mean use this again?

16:19:01 CAPT: It's on the stop now, its on the stop.

16:19:04 F/O: Well not according to that it's not.

16:19:07 F/O: The trim might be, and then it might be uh, if something's popped back might be mechanical damage too.

16:19:14 CAPT: I think if it's controllable, we oughta just try to land it.

16:19:16 CAPT: You think so? Ok lets head for LA.

16:19:21 [Sound of three thumps]

16:19:24 F/O: You feel that?

16:19:26 CAPT: Yea.

16:19:29 CAPT: Ok gimme sl....

16:19:33 [Sound of two clicks similar to the sound of slat/flap movement]

16:19:37 [Sound of extremely loud nose and the sound of background noise increasing, which continued until the end of the recording] [Sound of loose articles moving around in the cockpit]

16:19:43 F/O: Mayday

16:19:49 CAPT: Push and roll, push and roll.

16:19:54 CAPT: Ok, we are inverted...and now we gotta get it.

16:20:04 CAPT: Push push push...push the blue side up.

16:20:16 CAPT: Ok now lets kick rudder...left rudder left rudder.

16:20:18 F/O: I can't reach it.

16:20:20 CAPT: Ok right rudder...right rudder.

16:20:38 CAPT: Gotta get it over least upside down we're flying.

16:20:49 [Sounds similar to engine compressor stalls and engine spool down]

16:20:54 CAPT: Speedbrakes.

16:20:55 F/O: Got it.

16:20:56 F/O: Ah here we go.

16:20:57.1 F/O: [End of recording]
There is more to the business of aviation than making money.

Wes Bucey

Wow! That was harrowing just reading it. I can only imagine how it must have been to hear it first hand.

I agree - folks ought to have to hear that recording before being assigned to the job of checking any product where life, health, safety may be involved.

This thread sort of harkens back to the earlier thread on "bosses from he!!" in that there are some psychopaths in charge who willingly forego safety checks and necessary quality checks to put a few more pennies in their own pockets or even grab just a few seconds more time to suck a cigarette or drink some coffee.

We really need a better system to weed those mentally ill people out of positions of power. Any ideas on how to make the "psychopath sorting" mandatory?

(I think this situation is separate and apart from the Deming concept of normal management responsibility, since it takes a special expertise to predict a psychopath who can be extremely devious and charming to gain trust one second and vicious and mean in the next second. I, for one, despite being experienced and cynical, have been sucked in by psychopaths and sociopaths on several occasions. The only difference is I did something to remedy the situation once the pathological behavior surfaced.)

Added in edit:
I want to make a distinction between
  1. the psychopath who knows what he is doing is wrong and just doesn't care
  2. the ignorant fool who has been ill-trained and doesn't have a clue about the ramifications of his actions.
The ignorant fools can be traced to either ignorant managers or psychopaths. I can help an ignorant manager learn, but I don't know any way to cure a psychopath, except to remove him from the situation.
Last edited:

Cari Spears

Super Moderator
Staff member
Did they ever determine the cause of the insufficient lubrication? Was the amount or type of lube specified in maintenance instructions incorrect? Was a maintenance operation missed?

Don Palmer

Alaska Airlines Submital to NTSB

Cari Spears said:
Did they ever determine the cause of the insufficient lubrication? Was the amount or type of lube specified in maintenance instructions incorrect? Was a maintenance operation missed?
A. Design
Flight 261’s horizontal stabilizer moved well beyond its normal mechanical limits, which resulted in a complete loss of control of the aircraft. The end stop on the jackscrew assembly did not prevent the jackscrew from sliding out of the gimbal nut and causing this loss of control.

Because Alaska was not a part of the Safety Board’s design review, we are not in a position to comment on the conclusions that should be drawn from that review. We trust the Safety Board will come to proper conclusions based on the information it has collected and analyzed.

B. End Play Measurement Procedure
The Boeing/MDC end play test procedure did not, and could not, accurately measure the wear of the horizontal stabilizer jackscrew assembly. The flaws in this procedure prevented operators from accurately monitoring the condition of their MD-80 jackscrew assemblies.

C. Grease
Alaska Airlines properly lubricated the horizontal stabilizer jackscrew assembly on the accident aircraft. The gimbal nut threads suffered extreme wear and ultimately stripped as a result of the use of the Aeroshell 33 grease on the jackscrew assembly. Aeroshell 33 is corrosive to the material comprising the gimbal nut, and has wear rates three to ten times greater than wear rates associated with the use of Mobilgrease 28.

D. Flight Crew Performance
Captain Thompson and First Officer Tansky performed professionally, even heroically, in the face of a malfunction from which recovery was impossible.

Alaska Airlines respectfully submits that the National Transportation Safety Board should recommend the following:

A. End Play Test Procedure
Require that the current procedure for monitoring the condition of MD-80 horizontal
stabilizer actuators be replaced with an x-ray or ultrasound procedure.

B. Grease
Require all operators to discontinue the use of BMS-3-33 (Aeroshell 33) in all
applications containing copper or copper alloys.

I have not seen a final report from NTSB.

Don Palmer

Probable Cause(s) as declared by NTSB

The National Transportation Safety Board determines the probable cause(s) of this accident as follows.

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. Contributing to the accident were Alaska Airlines' extended lubrication interval and the Federal Aviation Administration's (FAA) approval of that extension, which increased the likelihood that a missed or inadequate lubrication would result in excessive wear of the acme nut threads, and Alaska Airlines' extended end play check interval and the FAA's approval of that extension, which allowed the excessive wear of the acme nut threads to progress to failure without the opportunity for detection. Also contributing to the accident was the absence on the McDonnell Douglas MD-80 of a fail-safe mechanism to prevent the catastrophic effects of total acme nut thread loss.
Two more interesting documents relative to the incident are attached. One is titled, "The Potential Adverse Effects of Grease Substitution" and is an NTSB safety bulletin, while the other is a letter of recommendation from the Aircraft Mechanics Fraternal Organization to the NTSB, which highlights other potential (administrative) problems at Alaska Airlines which might have contributed to the crash.