The U.S. Federal Aviation Administration (FAA) (Washington, DC) recently issued a special bulletin advising owners and operators of select Luscombe (Gilbert, Arizona) aircraft models to start inspecting the legs of the main landing gear (MLG) to detect and correct internal corrosion.
The bulletin applies to Luscombe’s Model 8, Model 11A, Model 11E, and Phantom 1 series.
The FAA explains that the Model 8 series airplanes have a history of MLG failures due to internal corrosion of the lower legs.
“The design of the lower leg allows for moisture to accumulate inside the leg above the axle, which makes it susceptible to corrosion,” the FAA writes. “Internal surface treatment and regular inspection of the lower legs may help mitigate gear failures due to corrosion.”
For owners and operators of affected aircraft, the FAA’s recommendations include installing a drain hole in the lower portion of the leg, performing repetitive inspections of the gear legs for corrosion, and cleaning and sealing the internal surfaces of the gear legs.
Other recommended steps include cleaning the legs internally with a wire brush before surface protection; cleaning the legs internally with a cleansing hydrochloric acid (HCl) wash; flushing with water; allowing the legs to dry completely; and treating with a sealant epoxy paint.
“We also recommend using x-ray or ultrasound inspection methods on the leg-to-axle joint as an effective way to detect internal rust during the initial or follow-on inspection of the gear leg,” the FAA writes.
The recommendations are not mandatory, according to the agency. For more information, the full bulletin can be read here
Source: FAA, faa.gov.