Seat and locking part dimension questions.

[GAHorn]

I don't know why Cessna calls for the seat stop to release by .10 above the rail so long as it will release at some point in the travel of the adjustment handle....I'd rather find the seat stop engaged than find it was not when I need it.

What if you had to evacuate? A guy with the "successful look" might not be able to quickly exit if he couldn't get his seat to release.

[jrenwick]

George is right. In my original installation, the reel was defective -- it wouldn't release at all. Cessna was aware of the problem, and they replaced it. That could be a safety issue in an emergency.

[170C]

You sure wouldn't want to find yourself in a situation where you couldn't move the seat back for egress. Mine seems to work as it is supposed to, but it does require the handle to be pulled to its full up position before the reel releases. A friend had one put on his Cessna 175 and he placed a couple of additional adel clamps on the cable to better secure it. I have not found it necessary to do so at this point.

[Bruce Fenstermacher]

I don't know why Cessna calls for the seat stop to release by .10 above the rail so long as it will release at some point in the travel of the adjustment handle....I'd rather find the seat stop engaged than find it was not when I need it.

What if you had to evacuate? A guy with the "successful look" might not be able to quickly exit if he couldn't get his seat to release.

How did I KNOW you were going to bring this up. Notice I did insist that seat release BEFORE the handle reached it's full travel.

Here are my thoughts. I feel it more likely the seat slip and cause an accident than the seat stop prevent me from exiting the aircraft should I have an accident.

If the aircraft is upright and I'm not incapacitated,I can get out with the seat forward. If I'm hanging upside down I'm not likely to be able to move the seat back. If I'm not capable of climbing out from the seat in the forward position because I'm incapacitated I probably won't be able to push the seat back or get out if I could get the seat back. If I'm being rescued my rescuers aren't like to need to move my seat back either for all the reasons I wouldn't and if the rescuers are equipped they are likely to cut me out no matter where my seat is.

Now I do no one thing. If my seat could never be moved back as in a defective unit or installation, I'd have to remove the darn thing before I could or would bother to get in and fly in the first place.

[hilltop170]

I have a drawer full of two different types of Cessna-provided seat stops that I refuse to install. Aero Twin in Anchorage has a heavy duty seat stop for $25 that replaces the little strap and pin in the aft track hole that is a positive stop that will not break.

Cessna seat stop

FAA/PMA seat stop kit

image.jpg (25.08 KiB) Viewed 7230 times

[bagarre]

Aero Twin in Anchorage has a heavy duty seat stop for $25 that replaces the little strap and pin in the aft track hole that is a positive stop that will not break.

That seems like REALLY nice solution that's looking for a problem.

[hilltop170]

Those little strap and pin stops also eat up the washers and roller wheels on the rear seat legs.

[Bruce Fenstermacher]

Richard we were talking about the Cessna secondary seat stop which attaches to the seat and stops it from going backward if the pin fails to hold the seat in postition.

Interesting seat rail stop though. My 170A has survived with just a single plain steel cotter pin at each end for as long as I've known the plane. (And yes, the same cotter pin. Its taken along time to get them bent "just right" why start over with a fresh one. )

[bagarre]

Those little strap and pin stops also eat up the washers and roller wheels on the rear seat legs.

OK, that does sound like a decent idea for the back stops on the rails. If people 'pull the pin and ride the roller coaster backwards', they will slam into the rear stop. A better solution would be to smack your passenger upside the head when they do it tho

I have an extra set of those machined seat-stops that you screw down onto the rail. With a band saw and a drill press, I could make a few nice stops.

On the note of the Cessna Secondary Seat Stop: Before taking your plane to the Cessna dealer, be SURE your rails and rollers will pass the AD. I called the local dealer and the lady was very clear that if the rails or rollers did not pass inspection they would have to replace them at shop cost. She mentioned it several times "Most people think their rails are OK but, we replace more than you'd think when doing the secondary seat stop"

[N2255D]

Those little strap and pin stops also eat up the washers and roller wheels on the rear seat legs.

My seats won't reach the aft stops so I don't have that worry . I have to take the back seat out to remove the front seats . The first couple of years I had the plane I would put the rear seat in twice after annual. The second install was after I tried to get the front seats in with the rear installed .

[Bruce Fenstermacher]

On the note of the Cessna Secondary Seat Stop: Before taking your plane to the Cessna dealer, be SURE your rails and rollers will pass the AD. I called the local dealer and the lady was very clear that if the rails or rollers did not pass inspection they would have to replace them at shop cost. She mentioned it several times "Most people think their rails are OK but, we replace more than you'd think when doing the secondary seat stop"

Well first your seats and rails should already pass the AD or your SHOULD be taking care of that first. And I suppose technically they feel they couldn't properly adjust the secondary seat stop should they install it and therefor they won't but otherwise the install has nothing to do with the other. And if they feel the seat rails or seat don't meet the standard you simply take the plane away. Home and do nothing if you want, to another shop if you want, replace the rails and repair your seat if you want. There is no legal requirement for them to do anything to your airplane and no legal way they can hold it is my point.

Perhaps she was just informing you that they see a lot of seat tracks and seats in their opinion that don't pass and that if you wanted them to fix that it would be time and material. That is fair and understandable.

But if you felt she was saying that most likely they would be billing you for seat tracks and seat repair in order to get the secondary seat track installed, take the plane to another Cessna repair station.

This conversation never came up when I had mine done at Moyer Aviation in Easton PA.

[bagarre]

Yes, we all SHOULD have rails that pass the AD

Perhaps she was just informing you that they see a lot of seat tracks and seats in their opinion that don't pass and that if you wanted them to fix that it would be time and material. That is fair and understandable.

But if you felt she was saying that most likely they would be billing you for seat tracks and seat repair in order to get the secondary seat track installed, take the plane to another Cessna repair station.

The repair station is the one at Fredrick KFDK and my impression from the conversation was option B.
"If the seats or the rails don't pass inspection, we'll have to replace those before installing the secondary device and that will be at shop cost to you".
She didn't mention an option to just take the plane away but I didn't ask about it either.

Either way, I'm safe as my rails and rollers are less than 2 months old.

[GAHorn]

My take on all this is that :
1. Cessna legal dept thought they needed to do something to belay the lawsuits from old, defective seat problems.
2. Cessna engineering dept developed this inertia-strap mod to alleviate the problem.
3. It probably does more to prove to critical personal injury lawyers that Cessna knew their system was poorly/defectively designed or they wouldn't be offering a free "kit" to modify the system.
4. Cessna marketing dept realized it'd be a bonus to get older airplanes into service facilities and make additonal sales if they'd offer something for "free".
5. It's a band-aid which complicates matters and I don't want it because I maintain my seat rails and locking systems and I have the secondary stops installed so my seat won't slide back too far to continue flying should the seat slip despite the fact that I insure it's locked prior to starting the engine.

I like the robust after-market stops posted by Richard. I never liked the cheap things Cessna installed and removed them by making my own out of robust 1/2" aluminum channel, AN clevis-pins, and circular-clips instead of cotters, ...but I may order the ones Richard posted simply because of their COLOR.

I wonder what Moyers thought of your ratplane-cotter-stops, Bruce?
(Or perhaps they sensibly and simply wanted to get the factory's warranty-labor and didn't care if the rest of the system worked properly or not... after-all, they apparently did not care about your locking-lever interference with the seat skirts. ...or did that malfunction not exist at the time of installation?)

As for evacuation, ... I believe it far more likely that minor injuries and such might make evacuation with malfunctioning seat release problematical than hanging upside-down and unconscious. If your back is injured you may not be able to squirm out of a seat which refuses to release, and rescuers will also be hampered. Fuel raining down and other hazards might be an issue. You may also be underwater and upside-down and need that seat to move! I see it no different than seat belts which refuse to unlatch or doors which are jammed shut....Yes, they might be cut loose, but a pilot trapped between an instrument panel, a doorpost, and a seat which refuses to budge can be a problem. It's a major reason to brief passengers on exiting/evacuation, and to restrain baggage/cargo from shifting forward to block front seats from moving. (Which reminds me to consider a cargo net and/or reinstalling my own hat-shelf.)

(And you knew I"d bring it up because you are a professional also and you also consider such things at your workplace situation. I brought it up, of course, because I think many pilots who don't deal daily with training for emergencies might not think of it and may need reminding. You and I and many others here re-train every six months for this and may be more mindlful of evacuation issues than those who fly recreationally or have not recently been to recurrent trng. )

[Bruce Fenstermacher]

Moyers didn't say a thing about the cotter pins. In fact they reinstalled the old ones probably thinking they were some kind of special clip.

I believe the secondary seat stop worked as it should when it left Moyers. I can not say nor is it worth my time to figure out if the adjustment was hard for them to attain but after going over my seats which included stripping them down to the frame, I found the adjustment to be just to critical and hard to attain. Now that I've insured the seat upholstery does not restrict the adjusting handle movement there is plenty of movement and the the secondary seat stop releases readily when the handle is pulled.

[HA]

the installation instructions for the secondary seat stop reels (SK210-175) specify that they lock when the pin is 0.05" above the rail, and unlock at 0.10" above the rail. You just adjust the cable to set the release point, took a couple tries initially. I recheck them at the annuals.