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:
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.
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.
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.