Main Landing Gear: Lower Leg Internal Corrosion

1 FAA Aviation Safety SPECIAL AIRWORTHINESS INFORMATION BULLETIN SUBJ: Main Landing Gear: Lower Leg Internal Corrosion SAIB: CE-17-14 Date: June 5, 2017 This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin advises owners and operators of the JGS Properties LLC (Luscombe) Models 11A and 11E series airplanes and Luscombe Models 8 and Phantom 1 series airplanes of an airworthiness concern, specifically the need for inspection procedures to detect and correct corrosion inside the main landing gear (MLG) legs.

At this time, the Federal Aviation Administration (FAA) has determined that this airworthiness concern is not an unsafe condition that would warrant airworthiness directive action under Title 14 of the Code of Federal Regulations (14 CFR) part 39.

Background

The Luscombe Model 8 series airplanes have a history of MLG failures due to internal corrosion of the MLG 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. Internal surface treatment and regular inspection of the lower legs may help mitigate gear failures due to corrosion.

Recommendations

The FAA recommends that owners and operators of the affected airplanes follow the inspection procedures outlined in The Don Luscombe Aviation History Foundation (DLAHF) Service Recommendation (SR) #4, dated January 22, 1996. The DLAHF SR #4 provides instructions to install a drain hole in the lower portion of the leg, to perform repetitive inspections of the gear legs for corrosion, and to clean and seal the internal surfaces of the gear legs.

Steps 2 and 3 following the “Inspect” paragraph of DLAHF SR #4 provide instruction to tap the lower leg with a ball peen hammer to free rust flakes and to clean the legs internally with a wire brush before surface protection. In addition to these steps, we recommend the following actions be performed for rust removal:

• Clean legs internally with a cleansing muriatic acid wash • Flush with water • Allow legs to dry completely • Treat with sealant epoxy paint as specified in Step 3 of DLAHF SR #4

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.

These recommendations apply to both the conventional style and Silflex style MLG. The lower legs on the left and right side of the conventional MLG are identified with part number (P/N) 58383 and P/N 58383-1. The lower legs on the left and right side of the Silflex MLG are identified with P/N

2 083119-2. This recommendation also applies to parts manufacturer approval (PMA) landing gear leg parts produced by Univair Aircraft Corporation with P/N U58383 and P/N U58383-1.

For Further Information Contact

Ms. Jennifer Tsakoumakis, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; telephone: (562) 627-5264; fax: (562) 627-5210; email: [email protected].

For Related Service Information Contact

THE LUSCOMBE ENDOWMENT, 2487 S. Gilbert Rd. Unit 106, Gilbert, AZ 85295; telephone: (480) 917-0969; fax: (484) 762-6711; website: www.luscombe.org; email: [email protected]