Emergency landing after row of seats comes loose

[eolesen]

2ndGen, the article you're quoting is dated 03Oct12.

The information about the locking pin (and the soda & coffee...) came to light late on 04Oct12.

Late Thursday, American said the loose seats causing delays and cancellations this week were not the result of human or mechanical failure, as the airline once suspected.

Instead, the airline discovered that worn pins in the seat lock plunger on these 48 aircraft can get stuck in the unlocked position when coffee, soda or juice are spilled on it, essentially letting a row of seats come unhinged from their tracks in the floor.

If it is a plunger, that implies that it gets pushed in to release, no? Like this?

I've used pins like the one above on trailers to secure hitches & weight distribution bars -- the shaft has a pin & spring; compressing the pin frees the ball bearing at the tip and allows the pin to slide out, releasing the pin locks the ball bearing in place.

I've also had these types of pins fail due to corrosion -- when the pin gets jammed or stuck in the channel, the bearing isn't locked, and the pin can come out.



You guys are supposed to be mechanics.... Put aside the outsourcing issue for a second...

Is the AA seat using a similar style pin to what I've posted?

With tight clearances, it doesn't seem to be too far of a stretch to think that it wouldn't take a lot of corrosion or sticky goo (i.e. soda residue?) to really screw things up...


Better yet, could someone take a photo of the pin and post it, or email it to me and I'll post it?...

 

[Glenn Quagmire]

http://cbsdallas.files.wordpress.com/2012/10/seat-lock-plunger-mechanism.jpg

 

[eolesen]

Thanks, found another at that site:

Can't say I understand why they'd go with this type of clamp vs. something that is locked down with a wrench. It's not like seats are moved every couple of months, so why use a quick-release clamp in the first place? To save a couple minutes every couple of years?...

 

[1AA]

They have to find a easier seat locking device since TIMCO will be dealing with the seats from now on. There was never a problem in the past with any of the seats I had to deal with once it is in the tab locks in and you screw it down. It does not get any easier than that. It looks like now the company has to find an easier seat lock since the next generation of maintenance will be third party inexperienced, unqualified non licensed individuals who will work for peanuts. So where is the savings? Before you go off on TIMCO or third party maintenance this loose seat issue was a non issue. This is history in the making as they say when you check the history of chronic or repetitive problems. I wonder what the next issue will be that we never had a problem with before.

 

[2ndGENAMT]

This is the same basic design that I was working on nearly 25 years ago on DC-10's, to pop the latch/plunger up usually took a short pry bar due to the fact that the plunger was clogged and caked with everything imaginable....

E, to be able to bolt the foot to the track they would have to use something similar to the feet that hold the Lavs and closets in the seat track.. My "guess" is that if bolted to the track in this manner with the movement and vibration associated with a seat it would wear the track out prematurely...

IMO there is nothing wrong with the design. The feet go under the tang in the track the latch is pushed down into the track recess keeping fore/aft movement from taking place and the saddle on the aft feet and star nut on the forward feet keep tension between the feet and track.

This is the reason for my skepticism...

 

[eolesen]

Fair enough, and the deafening silence on who else uses this means it's not of the question that the guys at TIMCO screwed it up because they'd never seen that type before.

Just seems odd, with all the FAA induced hoopla over 16G upgrades, it doesn't look like that type of clamp would hold up over time.

 

[2ndGENAMT]

http://cbsdallas.fil...r-mechanism.jpg

Giggity!!

 

[Flying low]

Thanks, found another at that site:

Can't say I understand why they'd go with this type of clamp vs. something that is locked down with a wrench. It's not like seats are moved every couple of months, so why use a quick-release clamp in the first place? To save a couple minutes every couple of years?...

Just tighten that screw on the back. It will clamp it onto the track, unless the screw is stripped.

 

[WorldTraveler]

The question that remains thruout this discussion is why other airlines don't have the same problem... does AA uniquely use certain seats and locking mechanisms for its seats since other airlines also serve soft drinks, outsource maintenance....etc...

 

[2ndGENAMT]

The question that remains thruout this discussion is why other airlines don't have the same problem... does AA uniquely use certain seats and locking mechanisms for its seats since other airlines also serve soft drinks, outsource maintenance....etc...

Different management team??

 

[eolesen]

The question that remains thruout this discussion is why other airlines don't have the same problem... does AA uniquely use certain seats and locking mechanisms for its seats since other airlines also serve soft drinks, outsource maintenance....etc...

Someone (forget who after 16 pages) said that the seat was unique to AA.

 

[2ndGENAMT]

http://www.cnn.com/2012/10/05/travel/american-airlines-problem/index.html

A good read..
It has happened before!

 

[OldBubba]

What I've seen so far, Outsource maintenance workers are not cleaning the floor track, thus when installing the seat back in or moving them, the crap/debri is not letting the lock plunger fully lock down. It can look like it is down when in fact it is not!
The saddle screw does not keep plunger lock down! on the aft feet, you can still use a screw driver an unlock plunger.
Star nut is loosen on front leg so you can slide the chair more easyly, then tighten so the chair well not rattle.

So my conclusion is after a few (takeoffs) people push and pull on the seat, the plunger pops up and just star nut and saddle screw in the back or holding the seat. After a few more (take offs) people push an pull on the seat, the seat slide fwd or aft (more likely aft because people are ohwas pushing back in there seat, thats why its happening on take off) and we all know what happens.
I did do one of the Outsource planes.

 

[2ndGENAMT]

So you are a TIMCO employee??

 

[ReadyNow]

Here is TIMCO's version

American: TIMCO work not to blame

http://www.news-record.com/content/2012/10/04/article/timco_work_not_to_blame_american_says