Tom Downey wrote:...It is up to the buyer to ascertain if the aircraft is worth the asking price.
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That's why he'd better perform an airworthiness inspection. If a seller is afraid to have his airplane inspected for airworthiness, then he can forget about selling to me.
The actual shop that performs the inspection should be agreed to by the seller, but is
selected by the buyer. There's no reason that the seller should categorically deny the buyer his right to select the inspection facility. If the seller has a known problem with Joe's local Cessna dealer...then find a different one. But that's no reason to give the choice to the seller! (Meanwhile, if Joe told me that I could have his plane inspected by any shop other than his local Cessna guy.... then I'd quietly make sure I
visited that local Cessna guy and inquire as to why a local owner might not want him inspecting that airplane..... Perhaps theres a maintenance issue/argument Joe may have had with that inspector that I'd like to know about.)
Greg, a couple areas to look for:
1. Wing attach points. Inside the spar carry-through (hat section) is a machined aluminum "block" that is subject to serious corrosion. This is aggravated by aircraft being stored outdoors, wet, and the fact that a steel bolt (dissimilar mat'ls) goes thru it.
2. Rudder cables where they pass thru the rearmost bulkhead. A difficult area to inspect due to a lack of inspection holes. The cables may have to be withdrawn for proper inspection.
3. Tailwheel attach bracket. Especially the older, steel "box" bracket, which has a tendency to crack and crack out the "stinger" or rearmost section of the fuselage. The later, large, aluminum "fishmouth" bracket can also have difficulties in the area of the upper plate, just above the leaf springs.
4. The tailwheel main leafspring (lowest one attached directly to the tailwheel" should be suspect unless it's been changed recently. This is not an item that an owner will feel responsible for,.... just want you to know to plan on changing it if it's old.
5. Battery box corrosion. These are expensive new, and hard to find in good condition from salvage yards at decent prices.
6. Corrosion
above the headliner in the cabin area. If an owner won't let you unzip the headliner and inspect up there, pass on the airplane. (Tom, perhaps it would have been satisfactory for you to have opened up your headliner and allow his inspector to look up there. You could have closed it back up when finished.) Only a fool would not become suspicious and proceed to buy un-inspected, an airplane that an owner refused to let him look at, IMHO.
7. Gearbox. Lay on your back and look at that wide double row of rivets that run between the struts for wrinkles. Remove the main landing gear spring covers and look at the blocks/extrusions that hold the gearlegs where they pass into the fuselage for looseness, corrrosion, cracks. Inspect the gearbox below the floor for damage, condition. Jack the airplane and suspend it on a cradle and shake the gearlegs while they are not supporting the aircraft. They should not be loose.
7.1 Fuel Selector Valve. The early 170/170A aircraft used a brass Weatherhead (brand) valve which is not easy to find. The later 170A/B aircraft used a square/block/machined aluminum valve with check-ball/cams (subject to a rare AD regarding only valves shipped between 12/98-5/99, rarely applicable to 170s). The later valve can usually be inexpensively rebuilt with Orings, but if the valve is not rebuildable, it is a $1K item from Cessna.
8. Firewall. Look for wrinkles, indicating accident and hard landings.
9. Doorposts. The doorposts, front and rear, are the main strength of this airplane cabin area. The front doorposts are hollow shells riveted together. Inspect the fuel lines inside the upper area just forward of the doorpost, above the sidewalls. Wrinkled, corroded doorposts are a major repair and indicate a damaged airplane. Rear doorposts tie to the rear wing spar carrythrough and should be closely inspected. Remove the inner shell of the rear doorposts to inspect the flap/control cables in there for condition and possible chafeing.
9.1 - Door
hinges. The door hinges are getting scarce. The upper door hinges take a beating, expecially as folks use the door to brace themselves as they enter/depart the cabin, and as doors receive replacement weatherstips that are too bulky for the door to close upon without stressing the hinge. The left/pilot's upper hinge is especially scarce due to it's being the hinge most often abused.
10. Wing root area. Look for condition of fuel lines as they leave the tanks headed for the fwd doorposts. Farther out, check the inside of the wings generally for spar condition, and general condition. While the inside of the wings do not have to be shiney, if painted, be certain it is not to hide corrosion. (I once saw a fairly good-looking 170B that had once been on floats many years earlier. The wings were bright, shiney, silver inside....due to
paint! A bright light revealed serious, large area corrosion that the paint was intended to cover up. Chromate or epoxy polyamide is OK as long as it's preventive coating ...not a cosmetic disguise.
11. All control cables, aileron, flap, rudder, elevators.
12. Flap lever, ratchet and locking-pawl rivet. See the article in the MX Library marked "urgent" about this possible failure area.
http://cessna170.org/phpBB2/viewtopic.php?t=2231
13. Documentation. Look for undocumented repairs and modifications. 50 year old airplanes usually have several. Get them cleared up
before you buy it. Do not accept undocumented, unapproved mods/repairs.
Also, have a Type Certificate Data Sheet copy in hand, and actually confirm the engine model (and dash number), prop model (and length), generator, carburator, mag models, etc. with those listed in the TCDS. Any deviations must be documented and approved. The equipment list should be up to date, and all avionics should be listed on that list, and their serial numbers recorded in the aircraft logs. (You don't want to buy an airplane with a GPS that was stolen out of a different aircraft. If the actual serial numbers on the actual installed avionics differ from those described in the equipment list/logs, then find out why and get a signed bill of sale for them as well.