Cessna seat rails

[Javier Henderson]

May I refer you to:

http://www.kjsl.com/~javier/sb-1.pdf
http://www.kjsl.com/~javier/sb-2.pdf
http://www.kjsl.com/~javier/ad-1.pdf
http://www.kjsl.com/~javier/ad-2.pdf

That deals with the seat rails on Cessna single engine aircraft. It's
pretty straightforward, when the holes on the rails are elongated
beyond certain limits, or if cracks are observed, the rails need to be
replaced.

The deal is, these suckers are riveted, and the outboard rails appear
to be a pain to deal with... there's either a magic bucking bar I don't
know about, or maybe there are little Wichita-born elves that fit in
there.

So the question is, how does one deal with this seat rail replacement?

Removing them is easy enough, and a lot of the rivets are doable, but
some are not. How does one deal with the impossible ones?

Cherrymax rivets? #6 or #8 structural screws? Something else?

In case it matters, my plane is a 1973 182P, but I think the pain is
about the same in all cases.

Thanks,

-jav

[MikeM]

Javier Henderson wrote:

> The deal is, these suckers are riveted, and the outboard rails appear
> to be a pain to deal with... there's either a magic bucking bar I don't
> know about,

(Yes, we made one when my AI and I did it to my 182)

> or maybe there are little Wichita-born elves that fit in
> there.

I was the designated elf. I still have scars on my hands
>
> So the question is, how does one deal with this seat rail replacement?
>
> Removing them is easy enough, and a lot of the rivets are doable, but
> some are not. How does one deal with the impossible ones?
>
> Cherrymax rivets? #6 or #8 structural screws?

About 3 screws per rail...

MikeM
Skylane '1MM

[Newps]

"Javier Henderson" > wrote in message
...
> May I refer you to:
>
> http://www.kjsl.com/~javier/sb-1.pdf
> http://www.kjsl.com/~javier/sb-2.pdf
> http://www.kjsl.com/~javier/ad-1.pdf
> http://www.kjsl.com/~javier/ad-2.pdf
>
> That deals with the seat rails on Cessna single engine aircraft. It's
> pretty straightforward, when the holes on the rails are elongated
> beyond certain limits, or if cracks are observed, the rails need to be
> replaced.

A crack does not make the rail unairworthy. I forget the exact wording but
it is something like if a crack goes from one hole to another then it is
unairworthy. I have had a crack in one of the copilot rails for the 6 years
I have owned the plane.

[Javier Henderson]

MikeM > writes:

> (Yes, we made one when my AI and I did it to my 182)

Well, share! Seriously, got pic?

> I was the designated elf. I still have scars on my hands

Ouch.

> About 3 screws per rail...

#6?

-jav

[Javier Henderson]

"Newps" > writes:

> "Javier Henderson" > wrote in message
> ...
> > May I refer you to:
> >
> > http://www.kjsl.com/~javier/sb-1.pdf
> > http://www.kjsl.com/~javier/sb-2.pdf
> > http://www.kjsl.com/~javier/ad-1.pdf
> > http://www.kjsl.com/~javier/ad-2.pdf
> >
> > That deals with the seat rails on Cessna single engine aircraft. It's
> > pretty straightforward, when the holes on the rails are elongated
> > beyond certain limits, or if cracks are observed, the rails need to be
> > replaced.
>
> A crack does not make the rail unairworthy. I forget the exact wording but
> it is something like if a crack goes from one hole to another then it is
> unairworthy. I have had a crack in one of the copilot rails for the 6 years
> I have owned the plane.

Yeah, mine aren't cracked, and the holes were ok last year, but we'll
see how it goes this year, annual is next month...

-jav

[MikeM]

Javier Henderson wrote:
> MikeM > writes:
>
>>(Yes, we made one when my AI and I did it to my 182)
>
> Well, share! Seriously, got pic?

Its in my AI's toolbox (I have a key; how many other plane owners
have that?). If I remember, I will take my digital camera out
and snap a pic.

>>I was the designated elf. I still have scars on my hands

> Ouch.

They match the scars on my arms from when I replaced the fuel
bladders in the 182...

>>About 3 screws per rail...
>
> #6?

We used #8 MS Cd-plated structural screws with shakeproof
nuts, only in the places where it is impossible to get a
bucking bar...

MikeM

[Javier Henderson]

MikeM > writes:

> They match the scars on my arms from when I replaced the fuel
> bladders in the 182...

Let's not talk about that right now...

> We used #8 MS Cd-plated structural screws with shakeproof
> nuts, only in the places where it is impossible to get a
> bucking bar...

Honest question: is there a reason to not use screws all around? Are
they heavier? More expensive?

-jav

[MikeM]

Javier Henderson wrote:

> MikeM > writes:

>>We used #8 MS Cd-plated structural screws with shakeproof
>>nuts, only in the places where it is impossible to get a
>>bucking bar...
>
> Honest question: is there a reason to not use screws all around? Are
> they heavier? More expensive?

My AI is a rivet freak. He loves rivets. Personally, I would have been
inclined to use the screws, cost be dammed, in the event I ever have
to replace the seat rail again. AFIK, Accepted Practices specifically says
that it is ok to use a fastener inplace of a rivet.

ToeCutter? Chime in here.

MikeM

[[email protected]]

On Wed, 12 May 2004 11:42:28 -0600, MikeM > wrote:

>Javier Henderson wrote:
>
>> MikeM > writes:
>
>>>We used #8 MS Cd-plated structural screws with shakeproof
>>>nuts, only in the places where it is impossible to get a
>>>bucking bar...
>>
>> Honest question: is there a reason to not use screws all around? Are
>> they heavier? More expensive?
>
>My AI is a rivet freak. He loves rivets. Personally, I would have been
>inclined to use the screws, cost be dammed, in the event I ever have
>to replace the seat rail again. AFIK, Accepted Practices specifically says
>that it is ok to use a fastener inplace of a rivet.
>
>ToeCutter? Chime in here.
>
>MikeM

Will have to look for the generic rivet-to-fastener reference, but
here is one that is Cessna seat rail-specfic.

cut-n-paste from:

http://www.faa.gov/certification/aircraft/av-info/data/SAIB/CE-90-03R2.pdf

This SAIB advises all owners and operators of certain Cessna airplanes
listed below of the necessity
to install all required fasteners when seat rails are being replaced.
Make Model
Cessna 150, 152, 170, 172, 172RG, 175, 177, 177RG, 180, 182, R185,
T182, 185, 188, 190,
195, 206, P206, 210, P210, 210-5, T303, 336, and 337

snip

c. Since it is difficult to install many of the rivets required to
attach the seat rail, it is permissible to
substitute screws with ultimate tensile strength exceeding 50 ksi.
Example of such screws are
AN515, AN520, AN525, MS35206, MS35207, MS35214, MS35215, MS35218,
MS35219,
MS51957, or MS51958 with lock nuts provided the holes are ream fit and
spotfaced.

sorry for the crummy formatting...

For a former Piper guy, I've had to change my fair share of Cessna
seat rails. Most of the rivets are reachable, if you really, really
want to.

It's been a few years, but I seem to remember that a couple of the
rivets in each rail were biguns. Am thinking that those got structural
screws to save the aggravation of pounding them.

Once upon a time was looking over a 172 before closing up the floor,
thought something looked "strange". Pilot's seat rails had been
replaced using only the pilot holes as described in the SAIB. Owner
got really ****y with me when I told him I needed to remedy the
situation.

Was a "first annual" on a
new-to-the-owner-never-been-on-the-field-before 'plane. I'm sorry to
say, I almost missed the missing hardware.

There was an under-floor stiffener missing also (mirror image was
installed under the co-pilot's side). Had a heckuva time convincing
Cezznuh to sell me another one. They told me that the stiffener wasn't
installed in the model-s/n range I was working on.

Told the parts guy he had a choice, he could either sell me the
"non-applicable" part, or I would remove the other one and mail it to
him...

Best part was the aircraft in question was purchased from an AP/IA and
there was no record of a seat rail change in the maint. records.

sorry for the length;

TC

[zatatime]

On Wed, 12 May 2004 21:15:30 -0400, wrote:

>On Wed, 12 May 2004 11:42:28 -0600, MikeM > wrote:
>
>>Javier Henderson wrote:
>>
>>> MikeM > writes:
>>
>>>>We used #8 MS Cd-plated structural screws with shakeproof
>>>>nuts, only in the places where it is impossible to get a
>>>>bucking bar...
>>>
>>> Honest question: is there a reason to not use screws all around? Are
>>> they heavier? More expensive?
>>
>>My AI is a rivet freak. He loves rivets. Personally, I would have been
>>inclined to use the screws, cost be dammed, in the event I ever have
>>to replace the seat rail again. AFIK, Accepted Practices specifically says
>>that it is ok to use a fastener inplace of a rivet.
>>
>>ToeCutter? Chime in here.
>>
>>MikeM
>
>Will have to look for the generic rivet-to-fastener reference, but
>here is one that is Cessna seat rail-specfic.
>
>cut-n-paste from:
>
>http://www.faa.gov/certification/aircraft/av-info/data/SAIB/CE-90-03R2.pdf
>
>This SAIB advises all owners and operators of certain Cessna airplanes
>listed below of the necessity
>to install all required fasteners when seat rails are being replaced.
>Make Model
>Cessna 150, 152, 170, 172, 172RG, 175, 177, 177RG, 180, 182, R185,
>T182, 185, 188, 190,
>195, 206, P206, 210, P210, 210-5, T303, 336, and 337
>
>snip
>
>c. Since it is difficult to install many of the rivets required to
>attach the seat rail, it is permissible to
>substitute screws with ultimate tensile strength exceeding 50 ksi.
>Example of such screws are
>AN515, AN520, AN525, MS35206, MS35207, MS35214, MS35215, MS35218,
>MS35219,
>MS51957, or MS51958 with lock nuts provided the holes are ream fit and
>spotfaced.
>
>sorry for the crummy formatting...
>
>For a former Piper guy, I've had to change my fair share of Cessna
>seat rails. Most of the rivets are reachable, if you really, really
>want to.
>
>It's been a few years, but I seem to remember that a couple of the
>rivets in each rail were biguns. Am thinking that those got structural
>screws to save the aggravation of pounding them.
>
>Once upon a time was looking over a 172 before closing up the floor,
>thought something looked "strange". Pilot's seat rails had been
>replaced using only the pilot holes as described in the SAIB. Owner
>got really ****y with me when I told him I needed to remedy the
>situation.
>
>Was a "first annual" on a
>new-to-the-owner-never-been-on-the-field-before 'plane. I'm sorry to
>say, I almost missed the missing hardware.
>
>There was an under-floor stiffener missing also (mirror image was
>installed under the co-pilot's side). Had a heckuva time convincing
>Cezznuh to sell me another one. They told me that the stiffener wasn't
>installed in the model-s/n range I was working on.
>
>Told the parts guy he had a choice, he could either sell me the
>"non-applicable" part, or I would remove the other one and mail it to
>him...
>
>Best part was the aircraft in question was purchased from an AP/IA and
>there was no record of a seat rail change in the maint. records.
>
>sorry for the length;
>
>TC

Thanks for all the info!

z