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BOEING HAS PROBLEMS
MEETING CUSTOMER DEMAND FOR MYLAR REPLACEMENT
by Tim van Beveren, Aviation
Editor, Miami
The MD-11 modification program of Swiss national Airline
Swissair got stuck already at its start. The reason: Boeing
cannot provide sufficient substitute material for the mylar
thermal acoustic insulation blanket replacement plan. In the
aftermath of the tragedy of Swissair flight 111, which crashed
on September 2, 1998 during an in-flight fire emergency killing
all 229 people on board the FAA had issued already in June 2000
an airworthiness directive ordering to replace insulation
blankets containing mylar from aircraft in service. This became
necessary after it was learned that mylar insulation blankets
might ignite and actually "fuel" a fire inside the aircraft
cabin. A potential high risk appears whenever blankets and
electrical wiring are in close vicinity to each other. An
electrical phenomena known as "arcing" can deteriorate the wire
insulation. An open flame, creating heat energy of some 1000
degree Celsius can thereby easily affect the mylar in the
vicinity and lead to a catastrophic fire behind closed panels,
as was the case on board SR 111.
Zurich based SR-Technics, who provides maintenance for the
Swissair fleet, had planned to already have modified a total of
three aircraft by today. However, due to a significant delay of
an actual nine month waiting period for replacement kits at
Boeing, only two aircraft where able to be modified so far. This
delay will require that those aircraft scheduled for heavy
maintenance due by autumn of this year will have to be grounded
for a second time in order to finish the modification. The Swiss
flag carrier currently operates a fleet of 19 MD-11 passenger
aircraft.
The airline that was directly impacted by a catastrophic fire
event on board of one of its modern fleet aircraft is not the
only one with problems to get enough replacement sets from
Boeing. A survey conducted last week revealed that there are
four other operators who admit that meeting the timeline for the
modification program of their MD11 is at risk. One operator even
calculated that this additional grounding period would cause him
an additional cost and revenue loss of 500,000 US $, - for each
aircraft of his fleet.
The Federal Aviation Administration (FAA) issued back in June
2000, as a reaction to the findings of the Swissair 111 crash
investigation, an Airworthiness Directive (AD-Note) ordering MD
aircraft operators to replace insulation blankets coated with
metalized mylar. Various substitute materials with a better
flame retardness than "Mylar" were already available in 1994,
but were more costly and installation was not required by the
aviation authorities at the time.
Boeing spokesperson Vicki Ray of the Seattle based aircraft
manufacturer said that Boeing "is trying to increase capacity"
to meet the growing customer demands.
However this problem got a new dimension with the February 6,
2000 recommendation of the National Transportation Safety Board
(NTSB). The NTSB pointed to new findings relating to a fire
emergency on board a Delta Airlines MD-88, which gave another
example of mylar blankets imposing a fire risk in
McDonnell-Douglas produced aircraft. During the flight on
September 17, 1999 from Covington, Kentucky to New York, the
flight crew reported a sulfurous smell and then, shortly after
that, fumes and smoke entered the forward cabin. The flight crew
declared an emergency and performed a landing at Covington
Airport in Kentucky. During the descent, a flight attendant
discharged at least one Halon fire extinguisher into a floor
grill, through which a "glow" was reportedly seen. The Board
investigating this accident urged the FAA to proceed faster than
the projected five-year compliance deadline for exchanging mylar
insulation blankets. The Board requested that the FAA issue an
airworthiness directive, requiring the replacement with approved
substitute materials "at the earliest maintenance opportunity".
The NTSB, already back in December 1999, while investigating a
fire incident in the forward cargo control unit of a parked
Delta Airlines MD-11 had pointed out to the FAA of the
potential hazardous risks associated with mylar
insulation blankets. Several pins inside an electrical control
unit vaporized when excessive electrical current hit the unit.
The vaporization created hot gases that escaped through the
units' back cover and ignited the adjacent mylar covered
insulation blanket.
FAA spokesperson Les Dorr confirmed last week that the FAA,
together with Boeing, the Canadian Transportation Safety Board
and representatives of the MD-11 operators, have just started
"phase four" of a special MD-11 modification program which
should lead to significant safety improvements in the worldwide
MD-11 fleet. The newly published nine additional Notices of
Proposed Rulemaking (NPRM) for wire modification and
improvements are also now part of this program. The deadline for
comments is April 6. These new AD's effectiveness is expected
shortly.
The last produced MD-11 was delivered to the German Lufthansa
Cargo this past Wednesday. This aircraft is the 200th MD-11 wide
body jet aircraft built in the former McDonnell-Douglas plant in
Long Beach, California. A total of 646 wide body aircraft were
built there during the last three decades. In 1997, the Boeing
Company merged with its financially struggling competitor.
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