The FAA has proposed a new Airworthiness Directive for inspecting wing spars for certain Piper aircraft.
Models affected include: 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.
FAA officials estimate that 19,696 aircraft will be affected by the AD.
According to FAA officials, they received a report of a fatigue crack found in the lower main wing spar cap on a Piper PA-28R-201. An investigation revealed that repeated high-load operating conditions accelerated the fatigue crack growth in the lower main wing spar cap. In addition, because of the structural configuration of the wing assembly, the cracked area was inaccessible for a visual inspection.
The FAA determined that the number of 100-hour inspections an airplane has undergone is the best indicator of the airplane’s usage history.
“Using the criteria in FAA Advisory Circular AC 23-13A, ‘Fatigue, Fail-Safe, and Damage Tolerance Evaluation of Metallic Structure for Normal, Utility, Acrobatic, and Commuter Category Airplanes,’ we developed a factored service hours formula based on the number of 100-hour inspections completed on the airplane,” FAA officials said in the proposed rulemaking document. “A review of the airplane maintenance records to determine the airplane’s usage and the application of the factored service hours formula will identify when an airplane meets the criteria for the proposed eddy current inspection of the lower main wing spar bolt holes.”
Only an airplane with a main wing spar that has a factored service life of 5,000 hours, has had either main wing spar replaced with a serviceable main wing spar (more than zero hours TIS), or has airplane maintenance records that are missing or incomplete, must have the eddy current inspection.
This condition, if not addressed, could result in the wing separating from the fuselage in flight.
FAA officials add they consider the AD an “interim action.”
“The inspection reports will provide us additional data for determining the cause of the cracking. After analyzing the data, we may take further rulemaking action.”
Estimated Costs of Compliance
To review maintenance records and calculate factored service hours, the FAA estimates two work hours at $85 an hour for $170 per airplane. Total costs for the U.S. fleet: $3.3 million.
The estimated costs to do the eddy current inspection, if needed, is $147.50 per wing spar, according to FAA officials. Add to that another $85 work hour for reporting the results to the FAA.
If the main wing spar needs to be replaced, estimated labor costs — for 32 work hours times $85 an hour — is $2,720 per wing spar. Add to that the costs of the part — $5,450 — and the total is $8,260 per wing spar.
Want to Comment?
Comments must be received by Feb. 4, 2019. Include “Docket No. FAA-2018-1046; Product Identifier 2018-CE-049-AD” at the beginning of your comments.
- You can comment online at at the Federal eRulemaking Portal
- Fax: 202-493-2251.
- Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.
- Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
All comments will be posted without change to the AD at Regulations.gov.
I have flow Pipers (PA-28-161,181,201R) PA32-300) in Bad T/storm where the Turbulence push the plane and pilot to their limit,they are really well engineered
however in aviaiton Safety is always first
problem is folks, this would not be seen during a normal annual inspection, this is what all the fuss is about, the mentioned bolts are “hidden” by the fuselage to wing area….having found cracks on another aircraft, has lead them to this…
You sound more knowledgeable than me on this subject, but In the article said it might have been a
manufacturing defect.
I will say one thing I am glad I was not in the left seat on this one!
I would like to think The FAA has our best interests at hart, But as I was always told The worst case for new laws are a one case problem. Yes this could have been really bad but to make this for the whole fleet
maybe not. So with that said do I have a solation No. I would have this checked on the annual when it come up. Now when the happen 2 or 3 times Yes have every thing in the fleet checked.
One thing that skews the hours in service, and the age of the spar is the flares that end up 20 feet above the surface. I’m sure we have all seen this happen, or experienced it. If it leaves no wrinkles, often no one is the wiser. I have replaced bent landing gear tubes; might want to factor in specific landing gear and other certain maintenance. I’m confident that there are high time Pipers with no stress issues. I’m just as confident that there are low time Pipers we need to be concerned about. A problem is, unless every pilot who drops one in admits it, and the hard landing documented, we have no sure way of knowing. This is why I like the high wing – don’t land on the structure you fly on. Just kidding.
In another aviation blog, a commenter brought up the fact that SOME airplanes are being signed off as annuals every time a 100 hr inspection is required … thereby masking the number of 100 hour inspections and the “type” of service the airplane is in. I owned a PA28 that was used in flight training but it didn’t fly enough to require 100 hr inspections early in it’s life. Later — when I bought it and In MY case as an A&P, the IA I work with wants me to sign off the work I do ahead of him as a 100 hr inspection but the airplane is NOT in commercial or flight training usage. So IF the FAA STRICTLY applies 100 hr inspections as the usage criteria, the calculation of “factored usage hours” required by the AD could be skewed.
Furthermore, I think that the relatively ‘young’ age of the accident airplane points toward manufacturing defects being induced in some way? Older Pipers — some with very high time — aren’t falling out of the sky … and some of them have been used in hard service AND have high time.
I am going to make a comment in the Federal Docket recommending to the FAA that they allow SOME latitude for the IA making the very first determination of “factored service hours” on the wing to take into account such occurrences. Once the first “baseline” count has been determined, subsequent calculations can flow from there. IF there is any question, the IA could consult the FSDO. Not a big thing but — still — an issue.
Then there’s the unseen issue of damaging the bolt holes in the two lower spars during the removal process. Even the AD cautions that removal could be an issue. So how the heck is the bolt going to be able to be removed if it gets “stubborn?”
I think this AD is apt to be changed for various reasons. With SO many Pipers flying with no particular issue, I think this AD is going to do more harm than good overall ?? Time will tell.
This kind of business is never pleasant when a fatal crash examination ferrets out an unsuspecting cause. I learned to fly in Cherokees in the mid 1970’s and were always reliable and solid.
I was in Flight Ops working for a check hauler that flew a flock of Barons. On the way back from Wichita Kansas just out of OKC an elevator horn snapped. Thinking this was an engine problem the emergency check found the vibration would not stop and the vibration so violent the pilot couldn’t read the instrument panel. He reduced power and was able to land at a nearby airport. A Service bulletin was issued after that and I don’t recall but I think the elevator horns were made from cast magnesium.
The thing about low wing airplanes with landing gear attached just outboard the fuselage we can plainly see the stress placed on the wing spar that requires attention like the Beechcraft series. It’s really heart breaking when fellow aviators perish from an anomaly such as that stress crack not easily seen.
they found fatigue cracking alright, in the wing that separated from the Arrow as it climbed away, killing an FAA examiner and a commercial pilot applicant