When to replace a prop?

On Feb 15, 3:53 pm, Doug Vetter wrote:
On Fri, 15 Feb 2008 10:02:19 -0800, Robert M. Gary wrote:
We also have an AD requiring mandatory overhaul
of blades that are 30 years old (just came out this month).

News to me and I've been following this fairly closely since our prop was
affected by the hub AD issued last year.

Care to provide the AD number or a link to it? I looked on Hartzell's
site and didn't find any such AD.

-Doughttp://www.dvatp.com/

If you are in the FAA's DB of having a plane in which a Hartzell prop
is applicable you should have gotten this in the mail...
Blades before D47534 are affected. Expect this to grow in the future.

AD 2007-26-09

Unsafe Condition
(e) This AD results from operators
requesting clarification of certain portions of
AD 2002-09-08. We are issuing this AD to
prevent failure of the propeller blade from
fatigue cracks in the aluminum blade shank
radius, which can result in damage to the
airplane and loss of airplane control.

-Robert

On Fri, 15 Feb 2008 20:52:19 -0800, Robert M. Gary wrote:
If you are in the FAA's DB of having a plane in which a Hartzell prop is
applicable you should have gotten this in the mail... Blades before
D47534 are affected. Expect this to grow in the future.

The little problem with the FAA's db is that it doesn't apparently take
into account airplanes upgraded with STCs like our 172 with the Avcon
180HP conversion. We haven't received any such notice.

I reviewed the AD you mention and it turns out that it is more or less a
revision and reissuance of AD 77-12-06(R2). Neither AD applies to blades
D47534 and above (production from 1977 on) because that's when they
figured out there was a problem and issued the original AD. Both ADs
require cold-rolling the blade shanks to prevent fractures and I believe
most if not all blades in service today have already been "hit" by this
AD. Our blades are older than the specified serial number but the shanks
were cold-rolled at overhaul in 1980. If I've read the AD correctly,
that means we're in compliance.

My prop shop told me Hartzell has indeed been "AD happy" the past few
years, but before people start freaking out at this it's important to
note that this AD does not require older blades to be retired by
default. It only requires them to undergo the cold rolling procedure and
thus be overhauled.

In the unlikely case your blade serial numbers are below D47534 AND they
have been overhauled so many times that they will not survive another
overhaul AND the shanks were not cold rolled at one of the prior
overhauls, then you'll need to buy new blades. Otherwise, you just need
to have them overhauled one more time to accomplish the cold rolling
procedure.

-Doug
http://www.dvatp.com/

On 16 Feb 2008 13:30:16 GMT, Doug Vetter wrote:

AND the shanks were not cold rolled at one of the prior
overhauls

Which would be pretty unlikely if they were overhauled at a reputable shop
sometime since the original AD was issued. I've never had an
engine/prop/accessory overhaul that did not include compliance with all
AD's existing at the time.
--ron

Well, ya just never know what little surprise you will find...

My Hartzell props are non-AD replacements to get the annual prop AD
off my back... Blades never nicked, never filed, etc.. Have under a
thousand hours on them... We weren't even looking at them as needing
service... But, I wanted to change out the front seal on the right
crank as it has a slight drip that keeps me busy cleaning things
off...

So, the little surprises began to happen...
When we pulled the right prop to do change the seal we found the studs
had been over tightened. Two nuts were slightly rounded off in
breaking them loose... Oh well, stuff happens and The Kid added new
nuts to the parts list... So, the seal is replaced, we hung the new
cylinders finally, and The Kid went to put the prop back on the next
day... I get this call at the office...

"you ain't gonna believe this."?", my wallet started to itch
immediately...

"Believe what?"

"The flywheel is cracked."

"Steve, in 50 years of owning airplanes and longer than that messing
with engines I have never seen a cracked flywheel on an airplane
engine."

"Neither have I, but it is cracked. I had just hung it on the crank
and lifted the prop up and as I was lining up the bolt holes the light
hit it just right and I saw the crack"

"Ah jeez... OK, leave it till I get there this afternoon."

So, I get there and sure enough, with the light "just right" you can
see the crack $$ So, I stare at the other prop and say, do you know
what I'm thinking... He says, yup, and we push the tool box around to
the left engine... Well, now I'm here to tell you the gorilla that
mounted the left prop must have used a 4 foot wrench to tighten the
studs... It took the better part of an hour of finesse and finally
resorting to a big drift and an even bigger hammer to get two of those
nuts broke loose... But the good part of that is after dye penetrant
the flywheel is not cracked... So now we have a new set of studs and
nuts for both engines on the parts list, and a flywheel - hoping to
find a used one for half the new price... Keeping old airplanes
flying is a full time job...

denny

On Mon, 18 Feb 2008 03:35:40 -0800 (PST), Denny
wrote:

Keeping old airplanes
flying is a full time job...

Oh yeah, especially when we try to do it with old parts.

Went years trying to get my airplane to have its annuals in the winter --
bringing it in the end of the month due, so it could be signed off the
following month.

Finally worked my way around to January.

Annual -- "you've got a cracked case".

After investigating options, I decided for a Lycoming factory overhaul.

Engine availability there (and elsewhere) was nil for a while. I wasn't
flying again until May sigh.

This year I finally got back to a January annual.
--ron

"The flywheel is cracked."

Ah, crap. This kind of stuff scares me. Sorry to hear it, Denny.

I'm hoping (IF my tires actually come in -- Desser must use the Pony Express
to ship) to wrap up our annual today.

Other than fishing the fuel gauge float out of the right main fuel tank
(which required removing and reinstalling the tank, twice. Don't ask.) and
reattaching it to the sending unit, replacing a brake rotor and tires, and
the usual myriad of brittle plastic repairs, this one looks like it'll be a
good one.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Jay Honeck wrote:
"The flywheel is cracked."


Ah, crap. This kind of stuff scares me. Sorry to hear it, Denny.

I'm hoping (IF my tires actually come in -- Desser must use the Pony
Express to ship) to wrap up our annual today.

Other than fishing the fuel gauge float out of the right main fuel tank
(which required removing and reinstalling the tank, twice. Don't ask.)
and reattaching it to the sending unit, replacing a brake rotor and
tires, and the usual myriad of brittle plastic repairs, this one looks
like it'll be a good one.

I am assisting a friend of mine with the annual on his -235. It is
becoming more of a restoration project than an annual. We removed the
right wing tank thinking that it would give us easier access to the
landing gear bolts on the wing. It didn't. But I do believe Piper could
have used a few more inspection covers thoughout the plane to make life
easier for maintainence. We had to replace the two little brackets that
hold the landing gear fairing on. They were broke on both wings. Now,
Piper uses two of the landing gear bolts to also hold on these little
brackets. What were they thinking?

--

Regards, Ross
C-172F 180HP
KSWI

Denny writes:

So, the little surprises began to happen...
When we pulled the right prop to do change the seal we found the studs
had been over tightened. Two nuts were slightly rounded off in
breaking them loose... Oh well, stuff happens and The Kid added new
nuts to the parts list... So, the seal is replaced, we hung the new
cylinders finally, and The Kid went to put the prop back on the next
day... I get this call at the office...


One wonders what the Last Guy used for a torque wrench...
Chicago Pneumatic, maybe?
--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

But I do believe Piper could have used a few more inspection covers
thoughout the plane to make life easier for maintainence.

I feel your pain -- but having just removed and reinstalled all 8 gazillion
screws that hold on the 3 gazillion inspection covers (and wheel pants, and
fairings, and gas tanks) -- I do NOT want any damned more inspection covers!

;-)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

"Jay Honeck" wrote in message
news:y7suj.39938$9j6.24450@attbi_s22...
But I do believe Piper could have used a few more inspection covers
thoughout the plane to make life easier for maintainence.

I feel your pain -- but having just removed and reinstalled all 8
gazillion screws that hold on the 3 gazillion inspection covers (and wheel
pants, and fairings, and gas tanks) -- I do NOT want any damned more
inspection covers!

No, they need to start putting the inspection covers on with Velcro! g
--
Jim in NC