mit wrote:I have been looking at these on all the cessna's I work on since the AD came out. I have yet to see a hinge in distress.
Only one for was recently, on a 205 (also omitted from the AD). I noticed a hinge pin had creeped out about an inch. Cotter pin was missing.
Tim have you seen any info on staked hinges vs cotter pin hinges?
mit wrote:I have been looking at these on all the cessna's I work on since the AD came out. I have yet to see a hinge in distress.
Only one for was recently, on a 205 (also omitted from the AD). I noticed a hinge pin had creeped out about an inch. Cotter pin was missing.
Tim have you seen any info on staked hinges vs cotter pin hinges?
I can't remember reading anything about the two as a preference. I was taught as a young pilot to look at the hinge on preflights also. It is too easy not to.
My take on this is that there are 3 versions of the aileron hinge (0523807): the first has the pin held in by a crimp/stake; the second has a cotter key; the third (current version) has a pin with an eye that holds it in place with a screw. The parts catalogs for both 170A and B show that P/N 0523807 is depicted as the crimped version suggesting that Cessna did not install hinges with cotters on newly manufactured 170As or 170Bs. At some point the hinge design was changed (P/N unchanged) and replacement versions had the cotter key. It is possible that the more updated hinge may have been installed by Cessna on some 170Bs about the same time the 172s started production. But I'll bet that Cessna will claim that the original hinge (crimped) was OEM for all 170A & B aircraft. The way I read the AD, it applies to all listed aircraft S/Ns. If, for some reason, a hinge on a Cessna 170 model was replaced with a part containing a cotter, then the AD applies to that 170 due to the style hinge installed. To answer the question of what other ADs might apply to our aircraft, it depends on equipment installed after original manufacture and is one of the reasons why we rely on experienced IAs who check these things on annuals. If an engine, propeller, appliance, airframe component, has an AD against it, it applies regardless of the airframe it gets installed on. (my opinion. I'll bet there are some exceptions)
Edit: After thinking about this, the FAA should have listed any airframe eligible to use that P/N on the original AD. This shows its too easy for something like this to slip through the cracks. Regarding the hinge design, the half attached to the wing is stationary and the other half riveted to the aileron moves with the aileron. Is the pin supposed to be able to rotate? Does this reduce wear on the stationary side? The hinges on my 170A appear to have the pin crimped/stationary. I have noticed that these hinges get dirty and need to be cleaned and lubed periodically. My ailerons move with no problem. Any answers/insights would be appreciated.
Well, this discussion is the reason I posted the original post. There have been numerous times in my career I've noticed this sort of oversight.
It seems to me that the AD misses the fact that hinge designs can and have changed over the years and that the different types can be interchanged. As everyone in attendance at the Bardstown convention mx seminar will recall, I brought this subject up when I presented the discussion regarding pre-flight inspections which we are likely ALL guilty of becoming lackadaisical.
(My own airplane has crimped hinges on the right wing and cottered on the left.)
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention. An originality nut (mostly) for the right reasons.
I can't remember George, had your plane had a wing damaged prior to its coming back to the US? That may have been when the cotter keyed hinges were installed.
My wings were rebuilt by Williams in Kendallville, IN during it's restoration. I don't know why they used different types.
(How many times am I going to have to explain that my airplane is not original. It's ME who is an originality-NUT.)
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention. An originality nut (mostly) for the right reasons.
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