Interesting break down of Alaska's MD 80 crash.

That is good. Especially when you fly a MD-80 series aircraft.
 
Also contributing to the accident was the absence of a fail-safe mechanism on the MD-80 horizontal stabilizer jackscrew trim system to prevent the catastrophic effects of total acme nut thread loss.
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Is there still no fail-safe mechanism of this system?
 
How much more fail safe do you want than a cable and pully system? My understanding is that the primary flight controls on the DC-9 series of aircraft are all cable and pully, and maybe I remember fo4ever explaining to me that there is a hydrolic boost somewhere in the system maybe on the rudder? But otherwise it's all cables and pullys. You can't get much more bulletproof than that.

BTW I'd guess if these guys had not tried to continue to run the trim they would have landed fine, not that they had any clue that the jackscrew was the thing tearing apart back there.
 
jtrain609 said:
How much more fail safe do you want than a cable and pully system? My understanding is that the primary flight controls on the DC-9 series of aircraft are all cable and pully, and maybe I remember fo4ever explaining to me that there is a hydrolic boost somewhere in the system maybe on the rudder? But otherwise it's all cables and pullys. You can't get much more bulletproof than that.

BTW I'd guess if these guys had not tried to continue to run the trim they would have landed fine, not that they had any clue that the jackscrew was the thing tearing apart back there.
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I don't disagree with what you're saying.. The way I read that was they were specifically referring to the jackscrew design.. and was asking the question to see if there had been something added and what that might be. I wasn't crticizing that there may not be some added failsafe. Proper lubrication through changed maintenance intervals/procedures may be adequate.
 
I get the impression that it is, they simply didn't take care of the equipment properly. I guess I look at it as saying, "Well why don't we have a backup to the lubrication and cooling system on piston engines? What if you forget to put oil in the engine?"

Dunno, don't forget to put oil in the engine? :)

There are just some things you need to do or somebody is gonna get hurt. Looks like this is one of them.
 
The DC-9 series is not the only aircraft that uses a jack screw to trim the horizontal stabilizer, quite a few other T-tail jets use a similar system. I really don't see the lack of a backup system as that big of a deal, these aircraft have flown for millions of hours and this was the first crash caused by a structural failure of this system. If the maintenance is done properly, then they have proven to be quite durable and safe.
 
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