Cessna seat rails

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

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/air...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

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/air...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