Airworthiness Notice - B066, Edition 1 - 25 March
2003
Insulation blanket covers and Tapes Metallized Polyethylene Terephthylene (MPET)
Purpose
To advise the Aviation Community on the hazards associated with the use of
metallized polyethylene terephthalate (MPET) insulation in aircraft
applications.
Background
During the course of the investigation into the causes of the 1998 Swissair
MD-11 airplane accident off the coast of Nova Scotia, the Transportation Safety
Board of Canada (TSB) expressed concern about metallized polyethylene
terephthalate (MPET), and "suggest that MPET cover material was a
significant source of the combustible materials that propagated the fire".
MPET is used as a cover material for thermal/acoustic insulation blankets and in
the manufacture of some reinforcing tape.
The TSB recommended that regulatory action be taken to eliminate the risks
associated with the use of MPET-covered insulation blankets in aircraft. It was
subsequently determined that certain DC-10/MD-11 and ATR 42/72, aircraft were
manufactured with MPET covered insulation blankets. Airworthiness Directives
have been issued to require the removal of these insulation blankets from the
above-mentioned aircraft. Transport Canada Civil Aviation (TCCA) believes that
there is no large transport or commuter category aircraft registered in Canada
with MPET-covered insulation blankets.
Discussion
MPET-covered insulation blankets are no longer being manufactured for
aircraft use. However, TCCA is concerned that some aircraft that were not
originally produced with MPET-covered insulation blankets could have had these
blankets installed during routine maintenance, wholesale replacement programs or
in conjunction with modifications, particularly prior to being imported into
Canada. Additionally, because it is not uncommon for Canadian owners/operators
to have maintenance checks performed at facilities outside Canada, there is the
possibility that MPET-covered insulation blankets may be routinely and/or
inadvertently installed as a replacement for damaged blankets as part of future
maintenance actions.
TCCA believes that owners/operators, maintainers and designers should be
cognizant of the insulation blanket replacement materials that have been, or
could be installed in their aircraft during routine and non-routine maintenance,
whether by an approved domestic or foreign maintenance organization.
Recommendations
Transport Canada recommends that owners/operators:
take the opportunity to verify the type of insulation covering installed
in their aircraft when fuselage interior liners are removed, particularly
for aircraft that have not been continually owned or operated since the date
of manufacture. Where it is determined that MPET covered insulation blankets
or tape is installed, TCCA recommend its removal;
ensure that when contracting maintenance services, the maintenance
organization is made aware that MPET-covered insulation blankets and
reinforcing tape is not to be installed as replacement material;
check their stocks of insulation blankets and reinforcing tape to confirm
that there are no MPET-covered insulation blankets or reinforcing tape with
MPET, and purge such stocks if found; and,
inform maintenance personnel of the potential fire hazard associated with
MPET.
Transport Canada also recommends that individuals and design organizations
approving aircraft modifications or repairs ensure that MPET materials are not
included in any list of parts, materials or specifications that comprise the
modification or repair.
For Minister of Transport
Director, Aircraft Certification
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