Wing Spar Corrosion Repair
What happens when a spar inspection finds corrosion, from cleanup within limits to a new spar.
Corrosion on a wing spar is how the Cessna carry-thru spar ADs started.
The 2019 T210M breakup in Australia began with a fatigue crack at a corrosion pit on the carry-thru spar's lower cap. Finding corrosion early and treating it correctly is the point of the inspection.
Here's what happens at each level.
Corrosion within limits
The Cessna carry-thru spar ADs require removing the corrosion, measuring how much material was lost, eddy current checking the area, and sealing it with primer and a corrosion-inhibiting compound.
Corrosion or cracks past the limits
If the material loss is past the AD's limit, or the eddy current test finds a crack, the AD's corrective actions apply, and that can mean a new spar. The FAA's replacement estimates:
- Piper PA-28 or PA-32 main spar: about $12,340 per spar (AD 2020-26-16). The 2024 proposal estimated about $14,383 per wing.
- Cessna 210 or T210 carry-thru spar: about $33,600 to $35,000 (AD 2023-02-17). Older 210s under AD 2020-03-16: up to about $43,600.
- Cessna P210: about $38,700
- Cessna 177 series: about $40,200
In May 2025 the FAA told theAustralian Transport Safety Bureauthat replacement Cessna carry-thru spar structures had been approved. That approval is not a new airworthiness directive. The inspection reports the FAA had received by September 29, 2023 are on theCessna 210 Carry-Thru Spar InspectionandCessna 177 Cardinal Carry-Thru Spar Inspectionpages.
Who does the repair
An A&P mechanic or a repair station does the corrosion treatment and any spar replacement. Spar replacement is major structural work, so choose a shop that has done your model before. We connect you with an eddy current inspector and, if you need one, a shop for the repair.
Related inspections
Wing Spar Eddy Current InspectionCessna 210 Carry-Thru Spar InspectionCessna 177 Cardinal Carry-Thru Spar InspectionPiper PA-28 and PA-32 Wing Spar Inspection