My
Recommended List of Items to Check during Pre-Buy:
This is not an
official list. This list is simply my
document of what I did do and what I should have done based on my first
purchase of a Grumman Cheetah. I would
recommend looking at the Annual Inspection list and review any items that could
be expensive to repair. The pre-buy is critical. There are some planes that
have been well taken care of and others that have only had the oil changed in
the last 26 years. I was not able to tell
the difference - even though I thought I could.
There is a TON of
data on the Grumman Gang archives:
http://www.grumman.net/archive/
Items to Inspect:
1.
Remove all the inspection plates.
2.
Bonding Glue. Everyone
is concerned with the “Purple Glue” blue bonding and the cream bonding. I would recommend that you be 100% certain
of which type you have and then decide for yourself if it is an important
issue. The only good specific
information I received on this topic was from David Fletcher:
“AA-5A's below 0106 are going
to be mostly blue bonding. Above 0145
are going to
be
mostly cream colored bonding. Aircraft
between these #s may be a combination
of
blue and cream parts. I don't have any
information from the Factory, these
are
only my personal observations. I would
welcome information from anyone with
S/Ns
in the middle that knows what their airplane is bonded from.
David
Fletcher
3.
Under the plastic cover over the landing gears you can inspect
the wing attach bolts and the all important wing spar. This information was carefully explained to
me by Bill Scott of Precision Engine before I purchased my plane. There have been a few planes ruled worthless
because the top of the wing spar is corroded.
Get a good mechanics mirror and light and look closely at the top of the
spar. There is only about 3/4" of
space between it and the top wing surface.
If these are touching, there is a good chance of corrosion. Expensive if it exists. Find out the history of the plane, where was
it kept, hangared, etc.. Again, the
best specific printed information I have on this topic came from David
Fletcher:
I
just received another request for a Traveler wing today. This is the fourth wing in the last year we
have been asked to replace due to corrosion on the spar. Most damage is on the spar inboard of the fuel
tank on Travelers. The Center spars are
also going bad, we have had to reject two Tiger, one Cheetah, one AA-1, and one
Traveler center spar from intergranular corrosion. All of these airplanes had spent time in Florida except the AA-1
which had a collection of rat nest in the wings. I would advise everyone to clean, prime and use a liberal coat of
corrosion inhibitors around the gear attach fittings, and the wing spar. Another spar problem I have run into with
early Travelers is the wing root fiberglass cutting (fretting) a grove into the
wing spar just under the black wing root seal.
This has totaled five in the last four years, two wings were on my
airplane. The repair is some what
expensive because the spar requires a stainless steel ring machined from a
solid billet and a DER 8130 sign off.
These wings did not have abnormal corrosion, just wear in the wrong
place.
David
Fletcher
4.
The torque tube that the front strut attaches can come loose and
is expensive to repair. Lay down upside
down with your head next to the rudder pedals and have someone move the front
nose strut. Also a good time to see if
the brakes are leaking. Any hydraulic
fluid around any of the four master cylinders should be noted.
5.
Remove the front nose strut and then the front wheel and check
the bearing that the nose strut rides in.
This is a good indication of the maintenance of the plane. If it is dry and worn, the plane probably
has not had the best care. Also
removing the wheels and checking the cleanliness of the wheel bearings will
help determine the care given to the plane.
There is quite a bit of information on this topic on the Grumman Gang
archives.
6.
Remove the tail cone and side inspection plates. View inside the tail section and aft
fuselage for damage, repairs, bent aluminum, loose bolts, etc...
7.
Remove the center console plastic and review the cables and
pulleys. If these are clean then the
plane has had good annuals. If there are fries and pop-tops, dust and grease
all over then you should be cautious and inspect more thoroughly.
8.
I personally was not so worried about the interior, avionics, or
plastics. These are all easily
repairable ($$). If the airframe and engine
are good, the rest is just selective upgrades.
9.
There is the Aileron AD to check.
10.
Be sure the plane flies straight. If it tends to turn left or right the owner will likely claim
that simple rigging changes will correct the problem. They are probably right, but it could be due to a bent horizontal
stabilizer or, worse, aft fuselage.
(This, I have heard, can happen as a result of snap rolls, high
turbulence IFR, hard landings, hanger damage, lawn mower incidents, tie down
storms, etc.. ) Make sure the plane flies straight or be willing to pay to have
the plane run through a rigging check.
If the plane re-rigs correctly and then flies straight, the deal is
on. If not the deal is off until
further investigation reveals the problem.
11.
The Engine. I am certainly
not an expert in this area. I knew I
was going for an engine overhaul when I purchased my plane so I was not careful
with the engine. (2450 hours TT on engine when I purchased) Have your mechanic review, compression test,
wobble test, bore scope, whatever checks they feel are necessary. I feel that without tearing the engine apart
and viewing for corrosion it is difficult to positively identify a weak engine.
Conclusion: No plane is perfect. Worry about the items that can get expensive
to repair. Minor dents and dings can be fixed.
Get a title search on the plane from the FAA. Also the FAA can get you microfiche of all title transfers, air
worthiness actions, 337's etc. The ones
you get from the seller may not be complete :)
FLY THE PLANE! Preferably with a Grumman experienced
pilot. This can tell you a lot.