Proposed wing spar AD for PA-28 and PA32 planes

Joe

"Factored service hours".
You must get your logs to see how many 100 hour inspections were performed and use the formula given to see if this may apply to your plane:
If you factored service life is calculated to be over 5000 hours or you have missing logs you will need an NDT inspection per this proposed AD.
https://www.federalregister.gov/documents/2018/12/21/2018-27577/airworthiness-directives-piper-aircraft-inc-airplanes

Scott Sherer

Thanks for the heads-up, Joe.

The FAA has just published an NPRM (Notice Of Proposed Rulemaking) of their intent to make an AD (Airworthiness Directive) for the following aircraft. Generally speaking, this AD is for aircraft with more than 5,000 hours. Here is a copy of the first paragraph of the NPRM:
"We (FAA) propose to adopt a new airworthiness directive (AD) for certain Piper Aircraft, Inc. (Piper) Model PA-28-140, PA-28-150, PA-28-151, PA-28-160, PA-28-161, PA-28-180, PA-28-181, PA-28-235, PA-28R-180, PA-28R-200, PA-28R-201, PA-28R-201T, PA-28RT-201, PA-28RT-201T, PA-32-260, and PA-32-300 airplanes. This proposed AD was prompted by a report of a fatigue crack found in a visually inaccessible area of the lower main wing spar cap. This proposed AD would require calculating the factored service hours for each main wing spar to determine when an inspection is required, inspecting the lower main wing spar bolt holes for cracks, and replacing any cracked main wing spar. We are proposing this AD to address the unsafe condition on these products.

This proposed AD would only apply when an airplane has either accumulated 5,000 or more hours time-in-service (TIS); has had either main wing spar replaced with a serviceable main wing spar (more than zero hours TIS); or has missing and/or incomplete maintenance records."

Also, note that this is NOT an AD at this time but subject to the NPRM process.

Joe

Scott,
That 5000 hours is based on a calculation That gives you "Factored Service Life"
My 180F has over 8000 hours TSN and the plane had nine ,100 hour inspections. Using the given formula my plane has 1317 "Factored Service Hours". Therefore this proposed AD would not apply to my aircraft. That number 17 in the formula is probably based on some kind of finite analysis done by the FAA and Piper.
Cut and pasted:

(2) Before further flight after completing the action in paragraph (g)(1) of this AD, calculate the factored service hours for each main wing spar using the following formula: (N × 100) + [T-(N × 100)]/17 = Factored Service Hours, where N is the number of 100-hour inspections and T is the total hours TIS of the airplane. Thereafter, after each annual inspection and 100-hour TIS inspection, recalculate the factored service hours for each main wing spar until the main wing spar has accumulated 5,000 or more factored service hours

https://www.federalregister.gov/d/2018-27577/p-53

Scott Sherer

Thanks so much, Joe. We'll all stay tuned and see how this plays out. I appreciate your getting the ball rolling. Merry Christmas.

Scott Sherer

Hi Joe,
I've pulled out my logs and done the calculation and it looks like my plane has 235 factored service hours. My guess is that high-time trainers with lots of 100 hour inspections are going to get caught by this. Still, while paying the bill is painful, it's better to know and fix the plane if it needs to be fixed.

arrow76r

Ok, I give up...As far as I can tell from the logs, my '69 Arrow has never had a 100 hour inspection, just 49 "annual" inspections. For purpose of the "factored service hours" calculations, is that the same? It has never been a trainer nor in commercial service so has never exceeded 100 hours in one year. According to the formula do I use 49 as the "N" factor? Or "0" ?

xr42il93

Jim, If you never had a 100 hour, then N=0. At least that's my read until this becomes a real AD.

xr42il93

How available is this eddy current test? Should I start looking around for a shop with that capability? Or is this something that most shops would have? (It looks like I'm a lucky guy with enough 100 hour inspections).

Scott Sherer

Wait until the real AD comes out and don't drive yourself crazy in the meantime. The real issue is how many 100 hour inspections are in your airplane history. See your A&P when the AD comes out.

arrow76r

Thanks, Joe!!

From the Federal register Joe cited:

"(3) An example of determining factored service hours for an airplane with no 100-hour inspections is as follows: The airplane maintenance records show that the airplane has a total of 12,100 hours TIS, and only annual inspections have been done. Both main wing spars are original factory installed. In this case, N = 0 and T = 12,100. Use those values in the formula as follows: (0 × 100) + [12,100−(0 × 100)]/17 = 711 factored service hours on each main wing spar."

Therefore, since my '69 Arrow has never had 100 hour inspections and is now showing 3670 hours TIS, I calculate the "factored service hours" to be (0 x 100) + [3670-(0 x 100)]/17 = 216. Since I fly about 70-80 hours/year and I am just over 75 years old now I could fly for another 64 years!!! FAT CHANCE!!!

Scott Sherer

I'm in the same boat (so to speak) Jim, I've had 4 100 hour inspections in my airplanes life against 4,000 total hours. It comes out to about 235 factored service hours.

Joe

"How available is this eddy current test? Should I start looking around for a shop with that capability? Or is this something that most shops would have? (It looks like I'm a lucky guy with enough 100 hour inspections)."

The EC head unit is pretty common in most aviation shops. I work in a prop shop and we have a really nice Olympus unit. Shops may/will need to buy the .375" hole probe and 90° probe, plus the EDM notched Calibration standard (NIST certified). Those are not standard to our shop but may be common in a tire and wheel MRO shop that is looking in the through bolt holes of a wheel for instance? I'll check with our on site level III NDT expert to see if he has a house/shop that can supply the required probe and cal standards.
Please keep in mind this is proposed. If you have an idea for an AMOC, now is the time before it is set in stone as an AD.

The way this is written they are really going after the flight school type operations. Think cyclic and fatigue issues. If you drone along for hours on end. The current formula given will not apply the EC inspection to your spar holes. If your bird has been flogged as a trainer with many 100 hour inspections, You _may _need to comply with the EC inspection.
I cut and pasted my response over in the Piper forum:
I have to say...It could have been far, far worse to all of us. The FAA did their homework IMO .
FAA did a good job of identifying the problem child airplanes. I read somewhere that this failure airplane had 63,000 Take off and landings in less than 8,000 hours. Think about that....
The accident airplane did a touch and go every .12 hours. I've done it, but not everyday. Its about 10 minutes a loop when performing touch and goes in the pattern. That being said I don't do that every day for years of an airplanes life. If you do... This is a problem that has hurt people due to the fatigue cracking of the spar that led to a wing separation and fatal accident.
I think the FAA did a good job instead of punishing all high time aircraft, they figured out away just the ones with the high cyclic loads via the 100 hr inspections. I'm sure that factor of 17 has to to do with some kind of finite analysis from the design. Sorry if your plane is applicable, but think about it...
If the plane has been used as a trainer, there is an issue. That issue could cost you your life. Seems like the Eddy Current inspection is sound, minimally invasive, and may keep the wing from folding... They could have made you take the wing off.
For the guys with missing logs...
If you don't know.... Do you really want that risk?

Scott Sherer

Nicely put. I've been thinking about some of the really high time ex-trainers out there. Between the ADS-B deadline and this AD I think there's going to be some quantity of Piper aircraft parted-out or sold off around the end of next year. We'll see how all of this shakes out.

Jmcmanna

I finally went through my logbooks...when I bought the Arrow, I didn't really look closely at the 100 hr inspections from 40 years ago. It had 34! Fortunately the TT is only about 4880, so I am coming up with 3482 service hours. But, since it won't be getting any 100-hrs while I own it, I guess I have a lot of time before I need to worry about it (assuming the AD doesn't change much in its final form).

Scott Sherer

Hi Jim,
Agreed. We'll keep an eye on the AD. It should be out by Spring time. We all have our fingers crossed but we'll all feel safer when it comes out.

ajinla21

So I guess I'm one of the really unlucky owners. My Arrow has 8000 hours on it, and 800 of those were with a flight school. It looks like it had 6 100 hr inspections (not sure why not 8), but the problem is I don't have complete records from before the flight school purchased it. I'm missing 9 years of air frame records. From the FAA document I ordered before I purchased, I can see the complete line of ownership. It seems apparent that it was not owned by any other flight schools. It seems I'll have to get the eddy current test. :-((

Scott Sherer

Hi AJ and thanks for your comments. After the eddy current test is done you'll know the plane is safe. On my last plane my A&P found corrosion that had pre-dated my ownership of my plane, which I had owned for about 13 years before it was found. It cost $8,000 to fix and at the time I was upset. My wife gave me a hug and said "we use this plane constantly and now we know it's safe. It wasn't safe for the last 13 years." She was right and the only way you can look at this problem is in that light. I know the money hurts, I get it, I've owned 8 planes. But in the final analysis you'll have a safe, trustworthy and reliable plane. And you're among friends on this forum that feel your pain. We're here to support you.

jimcurns

I have friends in the airline maintenance business and was shown how Eddy Current testing works. It's a brilliant and non invasive test. For a sense of how it works I have found a 5 minute video. The first 4 minutes are setting the testing parameters and the last minute give a sense of what it can do. The test piece of aluminum has three scratches or milled areas representing weak point of different depths used to calibrated the equipment. When the probe is run across a smooth non damaged area the wave line on the machine remains horizontal. When a defect is detected a vertical component to the wave is observed.

This testing takes training and a lot of knowledge to run, but my point is that once the unit is set up, and the test area is cleaned. Testing the subject area is quite easy.

Eddy current video

I hope this helps

Jim

Scott Sherer

Thanks so much, Jim. Most insightful and interesting.

ajinla21

Thanks for the kind words, Scott. Do you, or anyone else, know what the approximate cost of the eddy current test will be?

Scott Sherer

That's a good question. Right now the best advice is to expect 3 or 4 hours of labor. We'll get a better estimate when the AD comes out.

jlahofer

I am an ASNT Level 3 in eddy current, ultrasonic, dye penetrant, and magnetic particle, as well as the and owner and Responsible Level 3 of Aerohoff Inspection Services, Inc, based in Southern California. We travel around the globe offering our NDT services. We are the "Eddy Current Guys" and have been working with eddy current for over 30 years. We can assist with your NDT needs, and sign back to service through our FAA mobile repair station, so please feel free to contact us if you would like to set-up the eddy current inspection. www.aerohoff.com; sales@aerohoff.com; 760-567-4123 . Thank you.

Scott Sherer

Hi and thanks for the information. Do you have a name that we can use? Much thanks for your information.

jlahofer

Yes - sorry. My name is Jim Hofer with Aerohoff Inspection Services, Inc. C: 760-567-4123

Scott Sherer

Jim, welcome aboard. We have many members concerned about the Piper Wing Spar AD in the works. Anything to put our members at ease would be very welcome.

pitotdice

My advice is to become as familiar as possible with the proposed wing spar AD. In the mean time if you haven't complied with Service Bulletin 1244C, dated Dec. 3, 2018 I would strongly suggest that you order the kits, ($200.00, and the Aft spar attach bolts and locking devices, not expensive), and comply with this Mandatory Service Bulletin. (I know, Part 91 operators don't have to comply). Our 1976 Warrior with 4000 hours, never a trainer did well. With one exception: When the torque on the aft spar attach bolts was checked it did not meet the minimum of 160 Foot Pounds, close but not 160. We changed the attaching hardware, and noted no other problems. Waste of money before the AD? Not in my book. Once the AD comes out you will have to install the kits if they aren't already on your particular aircraft. Checking the torque is certainly worth the time. Not to mention a look in area most of us have not been able to look at. Peter Weiss

ShawnRich

My tech logs go back to 1979 for my 1974 Warrior. At that time, it had 3360 hours. I wonder if I assume worst case as it was obviously used in a training environment to accumulate that many hours in 5 years, then count 100 hour inspections going forward, if that would suffice. Doing that, I am not near 5000 hours factored service hours. I see a lot of 30 day/and or 50 hour inspections in the time frame (for a few years) since 1979 but not a lot of 100 hour inspections. I will look more closely at the annual hours, I guess. Not sure this formula is the most indicative of harsh since it is based on log entries. But it is better than assuming that a well used, babied aircraft would have an issue, I guess....?

Scott Sherer

All we can do at this point is wait for the AD to come out and deal with it. No matter what, we will have safe airplanes when we're done.

Scott Sherer

Flash! Flash! Piper CEO Simon Caldecott issues this letter to FAA: http://piperowner.org/piper-objects-to-proposed-ad-sends-detailed-letter-to-faa/

Harley Kleemann

Please send your comments to the email address contained in Simon Caldecott's letter. Piper wants to hear from us!!!

Scott Sherer

Roger that! I have great stories about Simon. He's a stand-up guy; A+ in my book. Not only is he doing an outstanding job running our favorite company, but he genuinely cares about us knowing full well that we'll probably never buy a brand new plane from him.