Removing sealant from wing leading edges and aircraft fairings

ChallengerGlobal

Oct 8

**Effectivity: Challenger 300, Challenger 350, Challenger 600, Challenger 601, Challenger 604, Challenger 605, Challenger 650 and Global Series aircraft**

ATA 53 and 57

Bombardier has received several reports of fuselage damage and wing skin damage in the form of tooling scratches generated during the removal of aerodynamic sealant and paint masking materials. These events have prompted the need to remind and caution technicians of the importance of using only approved tools, and following the recommended procedure and best practices for removing sealant and any paint masking materials.

In many cases, the scratches induced on the skin necessitated developing repairs using doublers and/or resulted in an airworthiness limitation item (ALI) mandating repeat future inspections. The use of metallic or non-approved tools could result in scribe lines, which may be hard to detect.

However these scribe marks could have significant stress impact and could provide the starting point for fatigue cracks or corrosion.

Maintenance personnel should always exercise care and follow the Structural Repair Manual (SRM)/Standard Practices Manual (SPM) procedures whenever removing sealant and paint masking materials. Particular attention should be paid when removing the aerodynamic sealant from the wing leading edges and around aircraft fairings, as well as removing paint masking tape around cabin window surround structure.

Bombardier only permits the use of non-metallic scrapers as indicated in the SPM. Using the proper tools to remove sealant will minimize any risk of damage.