Has anyone modified or does anyone know if it's even allowed to modify a seat track? My guess is it would be considered a major modification due the the system being modified. Swapping seats, not so much. Simple 337.

My situation is replacing the pilot and pax seat in the '55 180 with seats from a later model 185 that are articulating for the pilot and reclining for the pax (wife will be a lot happier on longer flights with the ability to recline). The newer seats have two seat pins each and the tracks that are installed are for the original one pin seats.

Can the existing un drilled track be legally drilled or am I buying new tracks all around? I don't think I can get by with just replacing one side but if someone knows better, I'm all ears.

Thanks, Rich

I would think that the only way to drill a decent hole in a seat track is to take it out & get it on a drill press or mill. I tried to drill a hole in the right-seat seat track of my old 170 for a halfway-back seating position and it came out really bad. Depending on the condition of your tracks, might be best to just buy a set of new McFarlane rails & install them. That should be just a repair- not sure if it's a major (requiring a 337) or a minor (just a logbook entry).

I'd install New tracks.

MTV

Different Cessna seat rails have the opening cut at different distances from the front end so that the later model seats will clear the door post when you go to take them out. The distance to the first latch hole from the front may be different also. You may also have to change the style of the window latches to clear the seat backs.

Tim

mtv wrote:I'd install New tracks.

MTV

I think that's the direction I'm going to go. I was able to get the s/n for the 185 they came from and McFarlane has them. They're going to put me back eight Benjamin's but having solid new tracks will be the right way to do the job.

Thanks for the comments.

Rich

bat443 wrote:You may also have to change the style of the window latches to clear the seat backs.

Tim

Good point. I'll do a check fit before having the upholstery done. I can always shave the foam at the shoulders for clearance and snug up the vinyl.

Thanks

Rich

PittsDriver wrote:..... McFarlane has them. They're going to put me back eight Benjamin's .....

Ouch!

Talk to the experienced mechanics or shops... I have heard that installing seat tracks involves bucking several rivets that are in an extremely difficult position to do correctly. The time and cost of installing the new tracks (by a shop that can do this the right first class way) may set you back a few more Benjamins that you weren't expecting.

If your existing tracks are in good condition, you may have the option of getting a 337 approval to add the holes in the right side track. To do this correctly you will need to have a little drill jig machined that puts the hole exactly in the middle of the rail. A machine shop will have to make this jig up for you. That costs something too, but it may be less than the total cost of new rails and installation.

I wouldn't drill the pin holes, you'll be money ahead with the Macfarlanes, they are a quality product.

Originally the seat tracks are installed before the floor is installed in the airplane putting the manufactured rivet head underneath against the thinner material, which is best practice.

You might consider removing the floor if you're going to replace all 4 tracks, it's really not hard. For a fast sheet metal guy it might actually be easier, I know it was for me! YMMV

Regarding removing the floorboards, you'll probably be able to remove a couple lbs of crud from underneath there!

https://www.amazon.com/Ryobi-A10FB1G-Fl ... bi+A10FB1G

Works well. You need a set of hex drive bits for this kind of chuckless unit. It is also good for drilling rivets in tight spaces.

lesuther wrote:https://www.amazon.com/Ryobi-A10FB1G-Flexible-Shaft-Holder/dp/B00P8HJF5G/ref=sr_1_1?ie=UTF8&qid=1470710891&sr=8-1&keywords=Ryobi+A10FB1G

Works well. You need a set of hex drive bits for this kind of chuckless unit. It is also good for drilling rivets in tight spaces.

As you can see in this photo I purloined from the Internets the floor section in question only picks up the 3 frames and the sills, very straightforward. This is a cool tool but not required for this operation.


As was suggested this is also an excellent opportunity to clean all the crud out of there.

Have you ever seen or used the AEROSTOP seat locks. Worked great on my 170 and friends 180.
You can lock them anywhere along the track. Not stuck with just one more hole.

There is a sh@#$ load of rivets to take out. Then days (hyperbole) of cleaning up and using air hose powered vacuum to clean out the loose stuff - then peek under with lights and mirrors to see just how much yuck has oozed back to the bottoms of the ribs / bulkheads. Used to buy the short low twist a/c drills by the dozens. For an original #39 drill hole and rivet we used a #40 drill and you generally get the rivet head to spin off without enlarging the original hole. Occasionally need a 1/16" drift punch to finish getting the rivet out. Used a light plastic hammer.

Chris C

So if you are pulling the floor out already, can you get a carbon fibre sheet to rivet back in? Or does one have to use aluminum again?

A1Skinner wrote:So if you are pulling the floor out already, can you get a carbon fibre sheet to rivet back in? Or does one have to use aluminum again?

Interesting idea, but it would take a minor repair and turn it into a major alteration in my book. One would need engineering data for the carbon sheet most likely, and then there's the corrosion concerns as well.

A lot of things are do-able but maybe not worth the time & expense.
How much weight are you really gonna save over the alum floor?
You gotta weigh benefit vs hassle.

Halestorm wrote:

A1Skinner wrote:So if you are pulling the floor out already, can you get a carbon fibre sheet to rivet back in? Or does one have to use aluminum again?

Interesting idea, but it would take a minor repair and turn it into a major alteration in my book. One would need engineering data for the carbon sheet most likely, and then there's the corrosion concerns as well.

I'm curious why the engineering data? The upper floor is not structural is it? I was under the impression that it is just covering?

A1Skinner wrote:So if you are pulling the floor out already, can you get a carbon fibre sheet to rivet back in? Or does one have to use aluminum again?

That would be a very poor material choice for that application. There are real live qualified engineers on this forum, and they can give you the numerical and material data backup for this, but for initial discussion purposes it is safe to say the carbon is not nearly as good as aluminum for fastener loads (rivets, screws, etc.), it will create abrasion and corrosion problems, and in a crash situation it can often become much more dangerous to the occupants.

A1Skinner wrote:

Halestorm wrote:

A1Skinner wrote:So if you are pulling the floor out already, can you get a carbon fibre sheet to rivet back in? Or does one have to use aluminum again?

Interesting idea, but it would take a minor repair and turn it into a major alteration in my book. One would need engineering data for the carbon sheet most likely, and then there's the corrosion concerns as well.

I'm curious why the engineering data? The upper floor is not structural is it? I was under the impression that it is just covering?

The seat tracks are attached to the upper floor, the pilot's seats are attached to the seat tracks, seems like a structural concern to me...

Halestorm wrote:

A1Skinner wrote:

Halestorm wrote:[quote="A1Skinner"]So if you are pulling the floor out already, can you get a carbon fibre sheet to rivet back in? Or does one have to use aluminum again?

Interesting idea, but it would take a minor repair and turn it into a major alteration in my book. One would need engineering data for the carbon sheet most likely, and then there's the corrosion concerns as well.

I'm curious why the engineering data? The upper floor is not structural is it? I was under the impression that it is just covering?

The seat tracks are attached to the upper floor, the pilot's seats are attached to the seat tracks, seems like structural concern to me...[/quote]
True enough.