So it's time for me to replace the seat rails on my 170. The locking pin holes are worn out of limits. My IA told me I should buy the screw kit for the install instead of rivits. Another good friend of mine told me the rivits were the only way to go. What are your thoughts on the subject?

Rivets are lighter generally and are self locking too. But, more skill to install correctly and/ or remove without damage to base frame/parts.

Not having done this repair myself, my limited understanding is that there are several places where it is really really difficult to get access to drive the seat rail rivets correctly. Remember you will be putting your arm through one of those 4 inch round holes, all the way up to your elbow, no visibility, then reaching over with the other arm, and maintaining the alignment of the rivet gun and bucking bar by feel, under very difficult conditions. The chances of rivets with a bad "shop head" are fairly high.

I believe there are true old-school sheet metal experts out there who can do this. But it is not your average modern day shop mechanic.

Are Cherrymax or Cherrylock rivets not allowed for this task?

I'd get McFarlane rails and rivet them in with solid rivets. McFarlanes are beefier and don't come pre-drilled so you can match the holes to the existing holes in the airframe.

It might be a pain in the ass to buck some of those rivets, but someone did it once all day every day. There are a ton of different bucking bar shapes, and you have to use a buddy. Get Bryan, he seems like he has some excess energy.

robw56 wrote:So it's time for me to replace the seat rails on my 170. The locking pin holes are worn out of limits. My IA told me I should buy the screw kit for the install instead of rivits. Another good friend of mine told me the rivits were the only way to go. What are your thoughts on the subject?

why go with the screws? are you going to replace the seat rails again when your grandkid wears them out?

A warning on older Cessna seat rails.
In the early 80s I sold my C-170 A to a pilot from Carp Ontario. The newly licensed pilot was doing hammerhead turns over Constance Lake ended up on his back, put the aircraft nose first into the ice and died. He left behind a pregnant wife and a two year old girl. Not enough airplane left to rebuild!

How do we know? His nephew was recording the low altitude wingovers for bragging rights.

The Transportation Safety Board (TSB) verdict: the seat was not properly latched and rolled back possibly causing him to hang on to the control column causing the A/C to roll on its back as the seat came off the rails.
Still have the newspaper article and picture to this day.
Always double check that the spring pin is all the way in through the seat rail and that a bolt is inserted in the rail at the furthermost rear operating seat movement, just enough to allow for entry in the cabin.
G.

My IA just replaced my seat rails using McFarlane seat rails. The rails were good quality and they fit well. He secured them usings rivets as he recommended.

On another note I always use a seat stop lock for extra security.

I agree with 8GCBC.
Personally I like a rivet install.
Sam

The seat rails where originally installed before the floor was riveted down, so some of the rivets are inaccessible. You will need some scrap aluminum to make a drill template off the removed rails. Now think out it folks, rivets are for shear, how is the stress on a seat rail, tension. Use screws, they exceed the strength of rivets manyfold. McFarlane ones are just fine, tend to be cheaper and available. Use NAS bolts if you want even more strength. However, if your seat rail happens to fail before your seat claws do, you most likely have exceeded your body's 10 g internal damage limit, so it is academic.

McFarlane rails with solid rivets is the only way. McFarlane rails come with a scrap piece of aluminum. It is a very easy install. It is easier to place a rivet and hold a bucking bar and pound rivets then trying to start a bunch of damn nuts through a little inspection hole, IMHO.

Rob, def go with the rivets. We just replaced mine in the Skywagon using McFarlane and bucked each rivet. McFarlane are for sure better than Cessnas. It was a pain to get to a couple of the backs, but not impossible. You can also reach the back of each either from inside or underneath via the insp ports. FYI... you are allowed to use "screws" if desired (lazy,) but each hole MUST be spot faced.

While we are on a Cessna seat/rails topic:
Is the end of this year the current deadline for Cessna to pay for the inertia reel safety install on the pilot seat?

Thanks in advance, guys.

Edit: Oh, and about what does/should it cost me to have the right seat done at the same time (P+L)?

Thanks for all of the replies everyone. I was leaning towards the rivits myself. Now the question is do I just bite the bullet and replace all 4 seat rails? or just the 2 rails with locking holes since they are the only ones that are bad. This might be one of those "since you're there might as well" kind of deals. It's only an extra $336 for the other 2 rails

Do em all, use the McFarlanes and rivet them. It is NOT true that some of those rivets are inaccessible. Mechanics have been replacing these things for decades....it ain't rocket science.

MTV

Littlecub wrote:While we are on a Cessna seat/rails topic:
Is the end of this year the current deadline for Cessna to pay for the inertia reel safety install on the pilot seat?

Thanks in advance, guys.

Edit: Oh, and about what does/should it cost me to have the right seat done at the same time (P+L)?

Yes it is, and there is ZERO reason not to get them installed. For the co-pilot side from a Cessna dealer you can expect to pay around $1,000.

See this thread for more info:
http://www.backcountrypilot.org/forum/2013-free-cessna-oh-s-t-seat-stop-12644

I've helped a fellow buck on some rails. It's not the end of the world. I don't think it would be any more fun to install screws.

If you are depending on the rivets (or the screws) for a shear load, then something is wrong with the design. The rivets (and screws) should be pre-loaded so there is little chance of a shear load on the fastener. That's why loose hardware can fail from fatigue (and wear) so quickly.

Zzz wrote:
you have to use a buddy. Get Bryan, he seems like he has some excess energy.

LOL

Barnstormer wrote: For the co-pilot side from a Cessna dealer you can expect to pay around $1,000.

$566.37 from Yingling-

I agree, get them done!!

I should have been more clear. The $1,000 I was quoted included installation.

Thanks guys, for the info. I think I have it (both fronts) scheduled before the new year...
It is a "soft" appt, as in, fit me in their schedule.