Cessna SEL-25-03

timwinters

timwinters

Ejection Handle Pulled
Joined
Feb 23, 2008
Messages
13,733
Location
Conway, MO
Display Name
Display name:
LTD
Holy crap...really?

This was supposed to be "the fix" for seat slippage but:

During routine assembly inspection, Amsafe determined that some 505590-403 Inertial Reel Assemblies did not exhibit the normal “clicking” sound during web retraction. Further investigation by Amsafe found that a component part had a slipping condition and that there could be an unintentional web spool out of as much as 6 inches of web when the assembly was continually cycled.
Amsafe has determined that the suspect inertial reel assemblies have a date code of "A0914".
Click to expand...

Here's the SEL:

https://support.cessna.com/custsupt/contacts/pubs/ourpdf.pdf?as_id=43821
 
timwinters said:
Holy crap...really?

This was supposed to be "the fix" for seat slippage but:



Here's the SEL:

https://support.cessna.com/custsupt/contacts/pubs/ourpdf.pdf?as_id=43821
Click to expand...


That system has had several SBs on it. Some relate to the reel, at least one other has to do with the actuating cable. It can be a finicky setup that needs care and attention. Care in the initial installation is critical to correct operation.

I'm sure Cessna (or McFarlane) would have come out with a totally redesigned seat rail system if there weren't so many roller housing and lock configurations on the seats. There must be a dozen different types out there, all running on the same rail profile. The steel-frame seats have roller housings welded to the seat frame, making any modification expensive.
 
Amazing that after all this time and money spent, this issue still exists.
 
Henning said:
Amazing that after all this time and money spent, this issue still exists.
Click to expand...

I could never understand why they went to those reels. I thought the finger trip lock on the slide rail was just fine.
 
The new issue is limited to reels that were manufactured in late 2014 only. The fraying cable issue was in the earliest installations. Overall the solution has been a very good one.

Anyone who advocates rail jamming stops like Saf-T-Stops and Aerostops has probably never had to exit a Cessna in an emergency. Doing so with those seat locks is not as seamless as some would imagine. If getting out in an emergency isn't important then those rail stops should suit you well.
 
Stewartb said:
The new issue is limited to reels that were manufactured in late 2014 only. The fraying cable issue was in the earliest installations. Overall the solution has been a very good one.

Anyone who advocates rail jamming stops like Saf-T-Stops and Aerostops has probably never had to exit a Cessna in an emergency. Doing so with those seat locks is not as seamless as some would imagine. If getting out in an emergency isn't important then those rail stops should suit you well.
Click to expand...

I'm amazed the they haven't just pulled the rails and put in better ones. It's not really a major ordeal to design a better set of rails. It may take a seat mod, but it wouldn't be a big deal either.
 
Henning said:
I'm amazed the they haven't just pulled the rails and put in better ones. It's not really a major ordeal to design a better set of rails. It may take a seat mod, but it wouldn't be a big deal either.
Click to expand...

You would think someone would have STCed the ultimate seat rail by now that includes seat fittings that are bolt and/or weld onto existing frames.

Worst case scenario the company could run an exchange seat program and modify them at the manufacturer, leaving only the rails to be installed in the field.

Stuff like this happens every day on corporate jets. (Think API Winglets substantial wing mod including, the ailerons and slats (if applicable)
 
Last edited:
bnt83 said:
Anything mechanical can have issues.
Click to expand...

Sure, but how long have we been installing inertia reel seat belt systems in cars? I would think a reliable and bullet proof design would be the norm by now.

Well, except for those made in China of course. I wonder if that's the issue here.

Edit: Yep, looking at Amsafe's website it appears as if a significant amount of their mfg'ing is done in China.

 
Last edited:
bnt83 said:
You would think someone would have STCed the ultimate seat rail by now that includes seat fittings that are bolt and/or weld onto existing frames.

Worst case scenario the company could run an exchange seat program and modify them at the manufacturer, leaving only the rails to be installed in the field.

Stuff like this happens every day on corporate jets. (Think API Winglets substantial wing mod including, the ailerons and slats (if applicable)
Click to expand...

Pilots are cheap and seek the cheapest legal solution. I'm not sure I would risk the investment required to STC it either when my solution would be considerably more expensive than the inelegant legal solutions available currently. With the Jet market you can charge what you need to to make it up in a few copies. That doesn't really work as well in the GA market. Granted, there's a lot of application available, but how many would choose a $5000 solution? How many would choose it at $2500?:dunno:
 
Cessna seat reels are not inertia reels. They're normally locked and unlock manually.
 
Pawl tolerance? Inadequate spring? Manufacturers farm out all the pieces. One of their suppliers likely missed on a QC tolerance. Close ones don't always show up on the bench and need some cycles to exhibit a problem. Simple fix. Some guys just need something to gripe about I guess.
 
Classic example of the negative aspects of GA. Any manufacturer would have to think long and hard before providing a real solution that would involve welding on 40+ year old seat frames, new rails, etc. Pilots won't pay much, the market is limited, and the liability is HUGE! There should be a liability waiver for the production modification of older aircraft parts when the safety benefits require it.
 
And as a counter point, I've owned and operated Cessnas in short and challenging operating conditions for 25 years and I don't want to change a thing. In that time I've changed several seat tracks and had a broken seat pin. No big deal. The failure potential is well known, has been for many years, and now is easier than ever to mitigate and with a more effective solution than has been available previously. What's the problem?
 
Stewartb said:
Cessna seat reels are not inertia reels. They're normally locked and unlock manually.
Click to expand...

How are they locked and unlocked manually? Is there a button on the reel that you have to reach under the seat to access?

Seems like this would be even more difficult than the rail locks in an emergency.
 
The unlock cable attaches to the seat adjust lever. When you lift the adjust lever the lock reel disengages.
 
Stewartb said:
The unlock cable attaches to the seat adjust lever. When you lift the adjust lever the lock reel disengages.
Click to expand...

Yup. Cessna had decided (or maybe the FAA did) that the secondary seat stop system had to be passive; that is, the pilot needed to do nothing more than usual to slide the seat back. In an emergency, like a fire on the ground, the panicking occupants don't need to be figuring out how to get the seat slid back.

The sad things are two: One, the seat locking system, if it's looked after properly, works just fine. It's the owners, or cheating mechanics, who let worn-out stuff keep flying and causing accidents. Two: some of the parts to fix these seats are obscenely expensive. Cessna would have better spent the money on offering seat parts inexpensively.

Dan
 
Seems to me that an enterprising young feller could find a source of hardened rail, draw up a set of plans on how to make it into a Cessna rail, and sell the PARTS to an owner for them to drill it and machine it up into an OMP (21.303(b)(2).

Same with rollers and side tangs.

Just a thought, mindya.

Jim
 
Stewartb said:
Cessna seat reels are not inertia reels. They're normally locked and unlock manually.
Click to expand...

It's my understanding that they are both actually.

Amsafe has determined that the suspect inertial reel assemblies...
Click to expand...

They manually lock and unlock, but the inertia reel is supposed to catch it should the manual system fail.

At least that's what I recall the paperwork stating when we installed mine.
 
Last edited:
You must log in or register to reply here.
Back
Top