PA28 and PA32 spar fatigue.

Not sure if this is the correct forum for this, however I have just received the CASA Airworthiness bulletin regarding PA28 and PA32 fatigue cracking of main spar and suggesting that an inspection will be necessary for airframes having 5000hrs or more. This will really put the cat among the pigeons, I am pretty sure there are more than a few PA28s with 20,000 or more hours!

The inspection will not be to painful.

AWB 57-017 Issue 1 - Piper PA-28 and PA-32 Wing Spar Fatigue

No PA-28 180 models on that list.

The difficulty is complying with a CASA AD based on the FAA AD will be in the calculation of "Factored Service Hours" as set out in this paragraph of the proposed AD:

Airworthiness Directives; Piper Aircraft, Inc. Airplanes

 

In explanation of the calculation method the FAA says, Airplanes used in training and other high-load environments are typically operated for hire and have inspection programs that require 100-hour inspections. We determined the number of 100-hour inspections an airplane has undergone is the best indicator of the airplane's usage history.

 

That might mean that privately owned aircraft might fall outside the scope of the AD because although they may have had many annual inspections during their lives, not many of them would necessarily have been 100 hours after the preceding annual inspection. If a privately owned aircraft had an M/R issued on 1st May, it might not rack up 100 hours by the next 30 April. Therefore it might be better to use TTIS since new. Many aircraft which started life as training school hacks will have their Factored Service Hours calculated from a the combined factored hours based on their life as trainers and then TIS based on hours accumulated since retiring from that lifestyle.

 

To my mind, however, if I owned an old plane, I'd fork out the money for the inspection just for piece of mind. The result would also assist in determining selling price.

Why would CASA issue this July 9 for comments by July 20? It has been out for months from FAA. Very few aircraft will meet the factored service hours test and need the inspection.

I think the bigger issue here is whilst flying along in yr PAxx knowing there is an issue with spars of the type in general is I wonder what my spar condition is like?? The second plane I ever bought was a PA28-140 but before I handed over the $$$$ I had the tanks removed and the interior gutted, cost me a few dollars but I sleep better at night!

Even if your exact model is not listed if it was mine I'd be getting the spar inspected. The PA-28R-180 Arrow is listed but not the PA-28-180 Cherokee/Archer. The main difference is retractables and a bit of extra weight. Most of these are 60s to 80s vintage so even if they haven't had the hours, age and environmental issues are against them. It might cost 2 or 3 grand to get it checked but I'd sooner have a lighter bank account and peace of mind than be a richer bloke in the cemetary.

I'm pretty sure the PA28 spars are routinely checked each annual due to their potential for corrosion with water sitting down there.

The puzzling thing is why the PA28-151 at all, and if this is included, why not the PA28-161 as well. They are identical aircraft except one is a 150hp Warrior and one is a 160hp Warrior.

I'm pretty sure the PA28 spars are routinely checked each annual due to their potential for corrosion with water sitting down there.

 

To get a good look at the wing corrosion the fuel tanks are removed and that does open a can of worms re corrosion if the wing has not seen light of day for 40 years. $12,000 later - fixed.

 

Plus we found an assembly fault going back 45 years where the steel bush for the bolt hole in the LH forward spar attachment plate was missing and the bolt holding the wing onto the fuselage there had flogged an enlarged hole in the aluminium plate due to wing movement!

 

To get a good look at the wing corrosion the fuel tanks are removed and that does open a can of worms re corrosion if the wing has not seen light of day for 40 years. $12,000 later - fixed.

 

Plus we found an assembly fault going back 45 years where the steel bush for the bolt hole in the LH forward spar attachment plate was missing and the bolt holding the wing onto the fuselage there had flogged an enlarged hole in the aluminium plate due to wing movement!

 

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Spot on! The normal annual will not find such corrosion hence I had my tanks pulled! It's a well known problem in Pipers just like the now worrying spars on the cantilevered Cessnas.

After the older company's factory was flooded the newer versions were never corrosion proofed as well as the earlier types, Commanache Aztec etc. Nev

The puzzling thing is why the PA28-151 at all, and if this is included, why not the PA28-161 as well. They are identical aircraft except one is a 150hp Warrior and one is a 160hp Warrior.

I wondered the same thing!

They may be identical models, but there's possibly a difference in the aluminium protection treatment from the factory.

I've seen some with extensive corrosion of the wing rear spar near the root.. Turned my youngest off ever flying in such things. You'd easily miss it if you didn't know were to look . Nev

They may be identical models, but there's possibly a difference in the aluminium protection treatment from the factory.

Strangely enough, in my ten years as a flying school LAME, the worst corrosion I found was on ‘factory protected’ examples. PA28, PA38 and TB10.