Cessna Wing Skins

My Cessna 172 M (1973) is being annualed. The top wing skin panels above the
wing tanks (Standard tanks) have to come off to inspect the area for
corrosion. We got all the screws removed. According to the service manual,
that is all that is supposed to be securing the panel. (Dozens of screws
around the perimeter of the skin and six screws around the fuel filler neck
is all that is stated to be removed). The skins would not remove after
careful tugging and pulling. (the fuel cap was removed for this).Then I
finally found three rivit type fasteners also around the filler neck. They
apparently hold the skin in place in addition to the six screws but there is
not any reference in the manual about removing them or drilling the heads of
the rivits off. If they are indeed rivits, they are flush head type because
they are smooth with the skin's surface. The heads are about 1/8th inch in
diameter. I was hoping they could be merely some alignment pins. I removed
the small inspection cover over the fuel transmitter (sender) to get a
better grip on the panel near the filler neck. When trying to gently lift
the skin panel upward, it is obvious that the three rivits are attached to
the panel and to a flange underneath the panel that apparently secures the
filler neck. The panel would not pop clear of them. So I don't think they
are alignment pins.
Anyone familiar with this to advise drilling these three fasterners to free
the panel?
Thanks,
Tom Cummings

And you're doing this why? Was corroision seen when you looked though
the (removeable) inspection plates? Has the tank been leaking? In 16
years of owner assisted annuals we've never had to pull skins up like
this.

jb


On Sat, 23 Apr 2005 17:30:59 GMT, "Tom Cummings"
wrote:

My Cessna 172 M (1973) is being annualed. The top wing skin panels above the
wing tanks (Standard tanks) have to come off to inspect the area for
corrosion. We got all the screws removed. According to the service manual,
that is all that is supposed to be securing the panel. (Dozens of screws
around the perimeter of the skin and six screws around the fuel filler neck
is all that is stated to be removed). The skins would not remove after
careful tugging and pulling. (the fuel cap was removed for this).Then I
finally found three rivit type fasteners also around the filler neck. They
apparently hold the skin in place in addition to the six screws but there is
not any reference in the manual about removing them or drilling the heads of
the rivits off. If they are indeed rivits, they are flush head type because
they are smooth with the skin's surface. The heads are about 1/8th inch in
diameter. I was hoping they could be merely some alignment pins. I removed
the small inspection cover over the fuel transmitter (sender) to get a
better grip on the panel near the filler neck. When trying to gently lift
the skin panel upward, it is obvious that the three rivits are attached to
the panel and to a flange underneath the panel that apparently secures the
filler neck. The panel would not pop clear of them. So I don't think they
are alignment pins.
Anyone familiar with this to advise drilling these three fasterners to free
the panel?
Thanks,
Tom Cummings

On Sat, 23 Apr 2005 21:46:31 GMT, (Jack
Brown) wrote:

And you're doing this why? Was corroision seen when you looked though
the (removeable) inspection plates? Has the tank been leaking? In 16
years of owner assisted annuals we've never had to pull skins up like
this.

jb

Well, I guess he's the third person who doesn't know the answer to the
poster's question!



On Sat, 23 Apr 2005 17:30:59 GMT, "Tom Cummings"
wrote:

My Cessna 172 M (1973) is being annualed. The top wing skin panels above the
wing tanks (Standard tanks) have to come off to inspect the area for
corrosion. We got all the screws removed. According to the service manual,
that is all that is supposed to be securing the panel. (Dozens of screws

Tom,
Use air tools and go slow.
Electric will create sparks and air tools will not.
Go slow to reduce heat build up.
Michelle (A&P)

Tom Cummings wrote:

My Cessna 172 M (1973) is being annualed. The top wing skin panels above the
wing tanks (Standard tanks) have to come off to inspect the area for
corrosion. We got all the screws removed. According to the service manual,
that is all that is supposed to be securing the panel. (Dozens of screws
around the perimeter of the skin and six screws around the fuel filler neck
is all that is stated to be removed). The skins would not remove after
careful tugging and pulling. (the fuel cap was removed for this).Then I
finally found three rivit type fasteners also around the filler neck. They
apparently hold the skin in place in addition to the six screws but there is
not any reference in the manual about removing them or drilling the heads of
the rivits off. If they are indeed rivits, they are flush head type because
they are smooth with the skin's surface. The heads are about 1/8th inch in
diameter. I was hoping they could be merely some alignment pins. I removed
the small inspection cover over the fuel transmitter (sender) to get a
better grip on the panel near the filler neck. When trying to gently lift
the skin panel upward, it is obvious that the three rivits are attached to
the panel and to a flange underneath the panel that apparently secures the
filler neck. The panel would not pop clear of them. So I don't think they
are alignment pins.
Anyone familiar with this to advise drilling these three fasterners to free
the panel?
Thanks,
Tom Cummings

Did you find corrosion? I'm not aware of any AD that requires removal of
the skins.
I would have thought that you A & E would be doing this if it was
necessary. - and would know how to do it.
Here is Canada, if my understanding is correct, you would be allowed to
remove the skins, but not allowed to reinstall them.
Sorry I'm unable to answer your question but I have one of my own.
Is there an AD? If so, maybe I'm going to have to do the same thing in
my 172H.

Tony

--

Tony Roberts
PP-ASEL
VFR OTT
Night
Cessna 172H C-GICE


In article .net,
"Tom Cummings" wrote:

My Cessna 172 M (1973) is being annualed. The top wing skin panels above the
wing tanks (Standard tanks) have to come off to inspect the area for
corrosion. We got all the screws removed. According to the service manual,
that is all that is supposed to be securing the panel. (Dozens of screws
around the perimeter of the skin and six screws around the fuel filler neck
is all that is stated to be removed). The skins would not remove after
careful tugging and pulling. (the fuel cap was removed for this).Then I
finally found three rivit type fasteners also around the filler neck. They
apparently hold the skin in place in addition to the six screws but there is
not any reference in the manual about removing them or drilling the heads of
the rivits off. If they are indeed rivits, they are flush head type because
they are smooth with the skin's surface. The heads are about 1/8th inch in
diameter. I was hoping they could be merely some alignment pins. I removed
the small inspection cover over the fuel transmitter (sender) to get a
better grip on the panel near the filler neck. When trying to gently lift
the skin panel upward, it is obvious that the three rivits are attached to
the panel and to a flange underneath the panel that apparently secures the
filler neck. The panel would not pop clear of them. So I don't think they
are alignment pins.
Anyone familiar with this to advise drilling these three fasterners to free
the panel?
Thanks,
Tom Cummings

Up to 5!

On Sun, 24 Apr 2005 05:47:16 GMT, tony roberts
wrote:

Did you find corrosion? I'm not aware of any AD that requires removal of
the skins.
I would have thought that you A & E would be doing this if it was
necessary. - and would know how to do it.
Here is Canada, if my understanding is correct, you would be allowed to
remove the skins, but not allowed to reinstall them.
Sorry I'm unable to answer your question but I have one of my own.
Is there an AD? If so, maybe I'm going to have to do the same thing in
my 172H.

Tony

The I.A. doing the annual said it is to be pulled and said he has seen
corrosion in planes like this before in this area. No fuel tank leaks. No
corrosion was seen through any of the inspection panels in the rest of the
aircraft. This large top skin panel is the only inspection panel in the fuel
tank area.
Tom
"Jack Brown" wrote in message
.. .
And you're doing this why? Was corroision seen when you looked though
the (removeable) inspection plates? Has the tank been leaking? In 16
years of owner assisted annuals we've never had to pull skins up like
this.

jb


On Sat, 23 Apr 2005 17:30:59 GMT, "Tom Cummings"
wrote:

My Cessna 172 M (1973) is being annualed. The top wing skin panels above
the
wing tanks (Standard tanks) have to come off to inspect the area for
corrosion. We got all the screws removed. According to the service manual,
that is all that is supposed to be securing the panel. (Dozens of screws
around the perimeter of the skin and six screws around the fuel filler
neck
is all that is stated to be removed). The skins would not remove after
careful tugging and pulling. (the fuel cap was removed for this).Then I
finally found three rivit type fasteners also around the filler neck. They
apparently hold the skin in place in addition to the six screws but there
is
not any reference in the manual about removing them or drilling the heads
of
the rivits off. If they are indeed rivits, they are flush head type
because
they are smooth with the skin's surface. The heads are about 1/8th inch in
diameter. I was hoping they could be merely some alignment pins. I removed
the small inspection cover over the fuel transmitter (sender) to get a
better grip on the panel near the filler neck. When trying to gently lift
the skin panel upward, it is obvious that the three rivits are attached to
the panel and to a flange underneath the panel that apparently secures the
filler neck. The panel would not pop clear of them. So I don't think they
are alignment pins.
Anyone familiar with this to advise drilling these three fasterners to
free
the panel?
Thanks,
Tom Cummings

I didnot find any corrosion. There is no A.D. for this. I just think the
I.A. is being thorough. I didn't mean to cause a false alarm.
The A.I. is not aware of the three little rivits or he would have pointed
them out to me. He is out of town this weekend and I thought I 'd check with
this group before he gets back on Monday.
Tom
"tony roberts" wrote in message
news:nospam-01806A.22502923042005@shawnews...
Did you find corrosion? I'm not aware of any AD that requires removal of
the skins.
I would have thought that you A & E would be doing this if it was
necessary. - and would know how to do it.
Here is Canada, if my understanding is correct, you would be allowed to
remove the skins, but not allowed to reinstall them.
Sorry I'm unable to answer your question but I have one of my own.
Is there an AD? If so, maybe I'm going to have to do the same thing in
my 172H.

Tony

--

Tony Roberts
PP-ASEL
VFR OTT
Night
Cessna 172H C-GICE


In article .net,
"Tom Cummings" wrote:

My Cessna 172 M (1973) is being annualed. The top wing skin panels above
the
wing tanks (Standard tanks) have to come off to inspect the area for
corrosion. We got all the screws removed. According to the service
manual,
that is all that is supposed to be securing the panel. (Dozens of screws
around the perimeter of the skin and six screws around the fuel filler
neck
is all that is stated to be removed). The skins would not remove after
careful tugging and pulling. (the fuel cap was removed for this).Then I
finally found three rivit type fasteners also around the filler neck.
They
apparently hold the skin in place in addition to the six screws but there
is
not any reference in the manual about removing them or drilling the heads
of
the rivits off. If they are indeed rivits, they are flush head type
because
they are smooth with the skin's surface. The heads are about 1/8th inch
in
diameter. I was hoping they could be merely some alignment pins. I
removed
the small inspection cover over the fuel transmitter (sender) to get a
better grip on the panel near the filler neck. When trying to gently lift
the skin panel upward, it is obvious that the three rivits are attached
to
the panel and to a flange underneath the panel that apparently secures
the
filler neck. The panel would not pop clear of them. So I don't think they
are alignment pins.
Anyone familiar with this to advise drilling these three fasterners to
free
the panel?
Thanks,
Tom Cummings

On 24-Apr-2005, "Tom Cummings" wrote:

I did not find any corrosion. There is no A.D. for this. I just think the
I.A. is being thorough. I didn't mean to cause a false alarm.
The A.I. is not aware of the three little rivits or he would have pointed
them out to me. He is out of town this weekend and I thought I 'd check
with this group before he gets back on Monday.
Tom


I suspect the A.I. may not be familiar with 172s, although this is kind of
hard to imagine -- sort of like an auto mechanic not being familiar with
Fords or Chevys.

Anyway, I will have to join the chorus of the bewildered. I co-owned a 172M
for many years and went through maybe 10 owner-assisted annuals. We never
once removed any wing skins. Our A.I. was super thorough, and he taught A&P
at a local technical school. Our plane was always stored outside in the
damp Pacific Northwest, so it's not like our chances for corrosion issues
were below average.

-Elliott Drucker

Thanks for clarifying that Tom
You had me worried

Tony

In article .net,
"Tom Cummings" wrote:

I didnot find any corrosion. There is no A.D. for this. I just think the
I.A. is being thorough. I didn't mean to cause a false alarm.
The A.I. is not aware of the three little rivits or he would have pointed
them out to me. He is out of town this weekend and I thought I 'd check with
this group before he gets back on Monday.
Tom
"tony roberts" wrote in message
news:nospam-01806A.22502923042005@shawnews...
Did you find corrosion? I'm not aware of any AD that requires removal of
the skins.
I would have thought that you A & E would be doing this if it was
necessary. - and would know how to do it.
Here is Canada, if my understanding is correct, you would be allowed to
remove the skins, but not allowed to reinstall them.
Sorry I'm unable to answer your question but I have one of my own.
Is there an AD? If so, maybe I'm going to have to do the same thing in
my 172H.

Tony

--

Tony Roberts
PP-ASEL
VFR OTT
Night
Cessna 172H C-GICE


In article .net,
"Tom Cummings" wrote:

My Cessna 172 M (1973) is being annualed. The top wing skin panels above
the
wing tanks (Standard tanks) have to come off to inspect the area for
corrosion. We got all the screws removed. According to the service
manual,
that is all that is supposed to be securing the panel. (Dozens of screws
around the perimeter of the skin and six screws around the fuel filler
neck
is all that is stated to be removed). The skins would not remove after
careful tugging and pulling. (the fuel cap was removed for this).Then I
finally found three rivit type fasteners also around the filler neck.
They
apparently hold the skin in place in addition to the six screws but there
is
not any reference in the manual about removing them or drilling the heads
of
the rivits off. If they are indeed rivits, they are flush head type
because
they are smooth with the skin's surface. The heads are about 1/8th inch
in
diameter. I was hoping they could be merely some alignment pins. I
removed
the small inspection cover over the fuel transmitter (sender) to get a
better grip on the panel near the filler neck. When trying to gently lift
the skin panel upward, it is obvious that the three rivits are attached
to
the panel and to a flange underneath the panel that apparently secures
the
filler neck. The panel would not pop clear of them. So I don't think they
are alignment pins.
Anyone familiar with this to advise drilling these three fasterners to
free
the panel?
Thanks,
Tom Cummings




--

Tony Roberts
PP-ASEL
VFR OTT
Night
Cessna 172H C-GICE