The FAA said it is investigating reports of corrosion on the forward wing spar attachments of Piper PA-28, PA-32, PA-34, and PA-44 airplanes following multiple discoveries of severe corrosion in the fleet of Pipers. Good inspection pays off—the corrosion was found by following the recommended inspection in Special Airworthiness Information Bulletin (SAIB) AIR-21-10 in a location that has been found to be difficult to access and assess the extent of the corrosion.
FAA’s East Certification Branch (ECB) recently issued an Airworthiness Concern Sheet (ACS) to highlight this concern and included photographs of the severe corrosion. The FAA is recommending operators of these aircraft inspect this area, per Piper Service Bulletin No. 1400A, and provide information including descriptions, photos, serial numbers, time in service and feedback on any difficulty completing inspection instructions. Corrosion is hardly a new issue and if you’re searching the used market for an aging Piper, be vigilant.
In its Special Airworthiness Information Bulletin AIR-21-10, the FAA advised owners and operators of a wide variety of Piper models to look out for the potential of corrosion on the forward spar-to-fuselage attach fittings—an area that isn’t easily accessible for inspection. While the provided photos of corrosion look pretty gnarly, FAA said it isn’t an unsafe condition that warrants an FAA AD. Still, corrosion spreads.
Piper has previously issued Service Bulletins SB 789A, 977, and 1244 to inspect for corrosion on the aft wing spar-to-fuselage attachment fittings. Because this aft area was said to be prone to corrosion because of water intrusion, the forward attachment fittings weren’t included in the bulletin’s inspection procedures. Several aircraft found to have severe corrosion in the forward-attachment fittings were operated in Florida and there wasn’t evidence of water intrusion in that area of the airframe. Instead, the FAA says the problem is galvanic corrosion between dissimilar metals (steel on the fittings and aluminum on the spar).
Obviously the plan should be an especially careful inspection of the forward wing attach fittings during each annual inspection or 100-hour inspections using the proper Piper maintenance manual. Park the airplane in moist, coastal areas? Even more important. The FAA said some owners have added borescope inspection holes installed for an easier look.
The agency said it wants to know about the discovery of corrosion on the forward wing spars, attachment fittings, and rivets on Piper PA-28, PA-32, PA-34, and PA-44 airframes.
This is just one reason of many why an aircraft should be disassembled when painted. Many make and models put steel and aluminum together.
did piper ever put jointing compound beteen steel and alum on contruction dont think so
Sure, but my understanding is that this would require removal of the wings. That’s fairly major disassembly (not as bad as replacing the carry-through spar of a 210/177, but definitely more work than removing control surfaces), and I’ve never seen that level of work performed for a paint job.
Removing wings on Piper Cherokees is not uncommon event when they live on the coast. Why spend 10’s of thousands on a paint job, avionics or engine and not inspect the most crucial structure?
The aircraft around here are disassembled. Damaged skins replaced and corrosion issues addressed. Then the wings, fuselage, tail feathers and many pieces are taken to a professional paint booth. The average aircraft is getting to be 50 years old. Disassembly inspections are good if you paint it or not.