PLEASE NEED HELP with Cherokee 180 metal bulkhead problem under back seat

On Tue, 5 Apr 2005 19:50:56 -0700, "kage" wrote:

Quite often hard landing damage such as this is prohibitively expensive to
repair. I suspect you'll find yet more damage inside the wings around the
landing gear attach points. People have tried unsuccessfully to make bush
airplanes out of Cherokees. Usually the airframe just gets bulldozed off the
side of some Alaska runway after a few months.

Karl

I agree, some people attempt to use planes like this for purposes they
were not built to withstand. But I don't think this was the case with
this Cherokee. Its been well tended by past owners, upgraded quite a
bit, and even preventative maintenance shows in the logs. Also, all
ADs show compliance in the logs. The last owner was a nice gentleman
up in Mass who used it to travel to see his son occasionally. And the
one before him was a minister in the northeast. So, no nuts in the
outback.

We've additionally been all over the wings and landing gear recently
(reoccuring AD on gear links) -- no problems at all. The wings and
fuselage don't show any wrinkling or other signs of high stress/hard
landings. This one frame member is the only damage we can find
anywhere -- and only on one side.

Luckily, I've been able to track down a couple places that have that
part on hand. It looks like it will cost a pretty penny to get it and
have it installed (a lot of riveting involved) -- but this one part
should resolve the problem.



Chuck

I wonder if this caused it:


FAA Accident/Incident Information
#FAA1 Accident/Incident Occurred on: 1991-10-18
Narrative: PILOT LOST CONTROL OF AIRCRAFT ON ROLLOUT. VEERED OFF
RUNWAY. LATER STATED CAUSE WAS A WIND GUST.







"C" wrote in message
...
Hi folks,

I ran into a little problem today.

Working on a 100hour just a month before the annual is due -- my
mechanic and I lifted the back seat to look at the cabling underneath.
Lo and behold -- we found a "tear" in an aluminum bulkhead under the
back seat.

The bulkhead is under the back of the rear seat and doesn't appear to
be structural as it is thin aluminum. But there is a steel brace
coming in from the flap area of the wing and rivited to the lower
outside corner of the aluminum bulkhead.

However on mine, just next to the steel brace on the baggage door side
-- there is a inch long tear up from the bottom of the bulkhead and a
small buckle in the aluminum brace above the tear. Its like there was
a terrific upwards stress on the bottom corner of the bulkhead where
the steel is rivited and it tore the aluminum bulkhead upwards.

Has anyone run into this problem before? I'd love to hear what had to
be done to repair/replace the damage. Maybe someone knows of a 337
that had been done to repair similar damage??? It would sure help my
mechanic who is a little unsure of where to start in the repair
process.

Thanks guys...



Chuck
N7398W

Steve Foley wrote:
I wonder if this caused it:
FAA Accident/Incident Information
#FAA1 Accident/Incident Occurred on: 1991-10-18
Narrative: PILOT LOST CONTROL OF AIRCRAFT ON ROLLOUT. VEERED OFF
RUNWAY. LATER STATED CAUSE WAS A WIND GUST.

Jeez, I hope not. That means it would have gone through 13 or 14 annuals
with no one noticing the crack!

--- Jay




"C" wrote in message
...
Hi folks,

I ran into a little problem today.

Working on a 100hour just a month before the annual is due -- my
mechanic and I lifted the back seat to look at the cabling underneath.
Lo and behold -- we found a "tear" in an aluminum bulkhead under the
back seat.

The bulkhead is under the back of the rear seat and doesn't appear to
be structural as it is thin aluminum. But there is a steel brace
coming in from the flap area of the wing and rivited to the lower
outside corner of the aluminum bulkhead.

However on mine, just next to the steel brace on the baggage door side
-- there is a inch long tear up from the bottom of the bulkhead and a
small buckle in the aluminum brace above the tear. Its like there was
a terrific upwards stress on the bottom corner of the bulkhead where
the steel is rivited and it tore the aluminum bulkhead upwards.

Has anyone run into this problem before? I'd love to hear what had to
be done to repair/replace the damage. Maybe someone knows of a 337
that had been done to repair similar damage??? It would sure help my
mechanic who is a little unsure of where to start in the repair
process.

Thanks guys...



Chuck
N7398W




--
__!__
Jay and Teresa Masino ___(_)___
http://www2.ari.net/jmasino ! ! !
http://www.oceancityairport.com
http://www.oc-adolfos.com

C wrote:
: The bulkhead is under the back of the rear seat and doesn't appear to
: be structural as it is thin aluminum. But there is a steel brace
: coming in from the flap area of the wing and rivited to the lower
: outside corner of the aluminum bulkhead.

: However on mine, just next to the steel brace on the baggage door side
: -- there is a inch long tear up from the bottom of the bulkhead and a
: small buckle in the aluminum brace above the tear. Its like there was
: a terrific upwards stress on the bottom corner of the bulkhead where
: the steel is rivited and it tore the aluminum bulkhead upwards.

Wow... that looks ugly. I just spend an inordinate amount of time looking at
the exact same area of my -140/180. We got FSDO approval for a 337 to add a -180
baggage floor back there. I spend 2 full weekends folded into a pretzel in the tail
of mine drilling out old rivets, drilling holes for, squeezing solid, and popping
blind new ones in.... all with the A&P saying, "Man, that looks uncomfortable." I was
quite disturbed about having to remove and replace a half dozen rivets on the
important-looking steel attach brackets in the corners. I'll be really ****ed if it
becomes an AD that requires removing the whole damn thing again!

I like the poster's explanation that it's a fore-aft torque that rippled it...
not a hard landing. A hard landing usually tries to push the mains struts through the
top of the wing, IIRC.

-Cory


************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

Steve Foley wrote:
I wonder if this caused it:


FAA Accident/Incident Information
#FAA1 Accident/Incident Occurred on: 1991-10-18
Narrative: PILOT LOST CONTROL OF AIRCRAFT ON ROLLOUT.
VEERED OFF
RUNWAY. LATER STATED CAUSE WAS A WIND GUST.

That very well could be it. Departing the runway on to rough ground
can cause the fore/aft stresses that generally cause these types of
cracks.

John Galban=====N4BQ (PA28-180)

Some years ago I repaired a Pawnee that had a similar steel plate on
the front spar. Because of the steel on aluminum, there was extensive
corrosion between and the aluminum rivets were soft enough you could
pick off the heads of the #6 rivets with your finger nail.

From the looks of the photo, there is lots of rust, meaning water.
Aluminum + steel + water = battery = corrosion. If it were mine, I'd
take it apart and look to see what is going on. If the aluminum is
corroded under the steel, you could get cracks under normal loads.

Don
A&P - IA

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On Sun, 10 Apr 2005 12:05:52 -0500, Don Hammer wrote:

Some years ago I repaired a Pawnee that had a similar steel plate on
the front spar. Because of the steel on aluminum, there was extensive
corrosion between and the aluminum rivets were soft enough you could
pick off the heads of the #6 rivets with your finger nail.

From the looks of the photo, there is lots of rust, meaning water.
Aluminum + steel + water = battery = corrosion. If it were mine, I'd
take it apart and look to see what is going on. If the aluminum is
corroded under the steel, you could get cracks under normal loads.

Don
A&P - IA

Don,

We've looked at it pretty closely. There is no corrosion involved.
And no sign of water infiltration. That was pretty clear from the
thick layer of dry dust all over the surrounding area -- I should post
another picture after vacumming the area out.

And worse yet, there are two cherry-rivets in the damaged area (you
can see one of them in the picture). That means that after the damage
- some "maintainer" bent the metal brace back down and stuck a couple
of cherry-rivets in it. Nope, he didn't bother to follow 43.13 and
repair it properly -- he just did a half-assed sorta-fix. And of
course -- he didn't make any mention of it in the logs.

Now -- it looks like I get to pay a DRE for a repair plan, probably
cut that brace a few inches away, get a replacement plate fashioned,
and splice it in. And probably pay a ton for a IA to do a bunch of
dye-penatrant testing while we're at it to insure there was no other
damage.

The thing that really ticks me off is I paid to have a prebuy/annual
done before purchasing the aircraft. With all this expense on a
pre-existing condition that should have been identified (we spotted it
FIRST time we looked under the back seat) -- I'm going back after the
IA who did the prebuy/annual. He's either going to help pay for this
repair -- or he can answer questions from the FAA.


Chuck

In case you were unable to see the cleaned up photo in the newsgroup I
have made it available here, in much better detail than the previously
posted photo of the bulkhead damage:

http://www.whodat.net/cherokee180/damage3.jpg

On 2005-04-11, Darrel Toepfer wrote:

posted photo of the bulkhead damage:

http://www.whodat.net/cherokee180/damage3.jpg

How hard do you have to land to do that?! Do the wings have dimples
above the gear?

--
Ben Jackson

http://www.ben.com/

Ben Jackson wrote:
On 2005-04-11, Darrel Toepfer wrote:

posted photo of the bulkhead damage:

http://www.whodat.net/cherokee180/damage3.jpg

How hard do you have to land to do that?! Do the wings have dimples
above the gear?


Wow. The first thing I did this weekend was grab a flashlight and checked
that area of my plane. It's perfect, thank goodness.

I wouldn't rule out some severe forward/backward motion of the wing
causing this, although it should be strong enough to take it.

If I'm not mistaken, the co-pilot side of this bulkead (the same side
shown in this picture) also has the external step reinforcement located on
it's rear side... Hmmm. maybe that's the next bulkhead back... I can't
remember.



--
__!__
Jay and Teresa Masino ___(_)___
http://www2.ari.net/jmasino ! ! !
http://www.oceancityairport.com
http://www.oc-adolfos.com