Commander 112a

frfly172

frfly172

Touchdown! Greaser!
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i know that the 112a wing has a life limit of 6945 hrs. Wondering if they have come up with a fix to extend the life , of the wing?
 
frfly172 said:
i know that the 112a wing has a life limit of 6945 hrs. Wondering if they have come up with a fix to extend the life , of the wing?
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I hadn't heard that, it sounds awfully low, and oddly specific. Normally I hear things like 12,000 hours.
 
FormerHangie said:
I hadn't heard that, it sounds awfully low, and oddly specific. Normally I hear things like 12,000 hours.
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Per the Type Certificate Data Sheet:

Screen Shot 2018-11-13 at 8.20.40 PM.png

The North American Rockwell Aero Commander 112 (as it was known then) was the first lightplane certified under the new Part 23, so perhaps they started out overly conservative. In any event, I've no idea why such odd numbers were selected for all the models.
 
So what do u do when u get there?? Replace the wing??
 
Pilawt said:
Per the Type Certificate Data Sheet:

View attachment 69094

The North American Rockwell Aero Commander 112 (as it was known then) was the first lightplane certified under the new Part 23, so perhaps they started out overly conservative. In any event, I've no idea why such odd numbers were selected for all the models.
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Aren't they all the same darn airframe?

Maybe Rockwell figured originally it should have a short life limit like the taxpayers airplanes it was building?
 
As odd and randomly specific as 6,945 is I find the 8,878 even more peculiar. You can tell that these are the straight result of some maths. Does wood fatigue?
 
And then not all flight hours are created equal. I’d think condition and inspections would factor in.
 
The COG is working on having that revised and has been working on it.

My 112A is just over 2k hours so I’ll never see the end of life.
 
There are a couple of 112a aircraft for sale with over 5k hours . The asking price seems to be reflected ,by the wing .
 
Problem is, every flight hour is reducing the value of the aircraft... Also, if the wing life of only 6945 is that critical, I guess we all need to be concerned that the wings are going to crack off? lol
 
I can't find the reference right now, but when I was researching before I bought my 114A, they were being very conservative. There are a lot of things in the Commander POH that have strange, oddly specific numbers. Having said that, there are significant changes in the 112A and B models. Per AOPA's write-up, the biggest thing was the addition of doublers to the main spar upper and lower caps for the A, B, and TC models.

Most 112s I see for sale are in the 3000 to 4000 hr range after 50-54 years of operations, so I doubt we will see a wing life extension kit since the original 112 airframes would be close to 110 years old when they reach the 6900 hr life limits, and there are fewer than 120 left on the US registry.
 
Chris Mixon said:
Most 112s I see for sale are in the 3000 to 4000 hr range after 50-54 years of operations, so I doubt we will see a wing life extension kit since the original 112 airframes would be close to 110 years old when they reach the 6900 hr life limits, and there are fewer than 120 left on the US registry.
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My 112A is high time, I could really use the spar fix that was being worked on but I haven’t heard anything in ages. There are wings out there.

Commander 112A FOR SALE
 
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Wow that's some very specific hours. There was a Nevil Chute novel about a part with a fatigue life known down to the hour where the hero had to stop a plane within hours of the number from flying. Or something like that.

The values listed imply four digits of precision which is poppycock for fatigue analysis, but it's still the law regardless. Just an algorithm at work.
 
Steamflyer said:
...There was a Nevil Chute novel about a part with a fatigue life known down to the hour where the hero had to stop a plane within hours of the number from flying. Or something like that...
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Wasn't that a movie in the 50's with Jimmy Stewart titled "No Highway in the Sky"?
 
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