Airworthiness Notice - B071, Edition 1 - 3 November 2004
Paint and Sealant Removal Process
Purpose
The purpose of this notice is to advise you that Transport Canada (TC) has
received reports from the Federal Aviation Administration (FAA) that some
commercial transport category airplanes from differing States of Registry have
been damaged in the process of being repainted in the mid-1990s.
The extent of this damage has rendered some of these aircraft beyond
economical repair.
Description
Damage has been reported along fuselage skin lap joints, butt joints, and
other areas of several aircraft. This damage appears to have been caused by the
use of sharp tools used during paint and sealant removal (possibly make of
metal, certain woods, micarda or hard plastic material) for removal of the
pliable fillet seals at the structural joints in the skin during the repainting
process. This use of sharp instruments can result in lines scribed in the
fuselage skin. This damage has also been associated with the trimming of large
external decals during their installation.
Lines scribed in the pressurized skin, if undetected, can result in cracks
and possibly lead to widespread fatigue damage.
Affected Aircraft/Engine Model and Series
Multiple scribed lines have been found on some Boeing 737, 747, 757 and 767
airplanes. Any airplane model where sealant has been removed from
fuselage joints, or on which large decals have been applied and trimmed on the
fuselage since original delivery, may be similarly affected.
Recommendation:
To ensure that sharp instruments or other tools that can damage the skin
panel are not used to remove sealant or trim decals, TC recommends that
manufacturers, operators and maintenance organizations, including refinishing
shops:
- Review sealant removal and paint stripping practices, procedures, and
tools used;
- Review training provided to affected personnel to ensure that they adhere
to standard practices and manufactures instruction for stripping of paint,
cleaning sealants, and general care of fuselage pressure boundaries; and
- During fuselage inspections, pay particular attention to any structure
that has been subject to refinishing, for evidence of scribed lines.
Standard practices for the removal of various coating can be found in the
Aircraft maintenance and Structural Repair manuals. FAA Advisory Circulars AC
65-15A and AC 43.205 also address the paint removal process.
Important References
FAA Flight Standards Information Bulletin for Airworthiness – FSAW 03-10B, dated November 20, 2003:
"Fuselage Skin ‘Scribe Mark’ Damage on Boeing 737 Aircraft." (www.faa.gov/avr/afs/fsaw/fsaw0310b.doc)
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