Transcript Electrical Problems May Have Sparked Swiss Air Flight 111

Polymers in Wire
Coating (Kapton)
Kapton is a registered trademark of E.I. Du Pont de
Nemours and Company
 CE 435 Into to Polymers
 Group Members
• Jason Womer
• Tom Hanselman
• Dan Boek
Table of Contents
 Wire Coating Specs
 Swiss Air Flight 111
 Fire Prevention
 Crash Statistics
 Improving Insulation
 Conduction of Polymers
 Uses of Kapton
 Degradation of Polymers
Insulation
Requirements for Wires
Requirements for Machinetool Wires and Cables
Who Sets the
Standards?
 Requirements specified in the
National Electrical Code
(ANSI/NFPA 70)
 Also used in the National Fir
Protection Association
Electrical Standard for
Industrial Machinery
(ANSI/NFPA 79)
How Are the Standards
Set?
 The polymer insulation and the
finished wires must comply
with a flame test and are for use
at temperatures of 90 °C (194
°F) or lower in dry locations
 Must comply at 60 °C (140 °F) or
lower where exposed to
moisture, oil, or coolants
NEC construction A (Nylon jacket not
used)
NEC construction B
Minimum average Minimum thickness Minimum average Minimum thickness Minimum thickness
thickness of the of any point of the thickness of the of any point of the of any point of
Conduct
insulation
insulation
insulation
insulation
nylon jacket
mm
Mils
mm
Mils
mm
Mils
mm
Mils
mm
ora size Mils
22 - 7; 20 - 30
0.76
27
0.69
0.38
13
0.33
4
0.1
12 AWG
15
10-Nov 30
0.76
27
0.69
20
0.51
18
0.46
4
0.1
9, 8
45
1.14
40
1.02
30
0.76
27
0.69
5
0.13
7, 6
60
1.52
54
1.37
30
0.76
27
0.69
5
0.13
5, 4 - 2
60
1.52
54
1.37
40
1.02
36
0.91
6
0.15
1/4/2000 80
2.03
72
1.83
50
1.27
45
1.14
7
0.18
213 - 500 95
2.41
86
2.18
60
1.52
54
1.37
8
0.2
kcmil
501 110
2.79
99
2.51
70
1.78
63
1.6
9
0.23
1000
a
A conductor is appropriate for use with a cross-sectional area that does not correspond to one of the AWG or kcmil
sizes in Table when the finished wire or cable complies with the marking requirement in and with each of the following:
a) The conductor shall have a dc resistance that is not larger than the resistance determined by interpolation(by crosssectional area) between the resistances of the next larger and smaller sizes shown inthe applicable Table or .
b) The number of strands, the thicknesses of insulation, the thickness of any nylon jacket, and other particulars
shallcomply with the requirements applicable to the next smaller size shown in Table .
Electrical Problems May
Have Sparked Swiss Air
Flight 111 Crash
* Pictures Taken from Web Site (http://www3.ns.sympatico.ca/mr.187/photos.html)
Urs
Zimmermann
(Pilot) and the
planes flight
recorder.
 The exact
cause of the
crash is
unknown,
however,
evidence
points towards
a rapid and
deadly
electrical fire

Rapid Fire
* Pictures Taken from Web Site (http://www3.ns.sympatico.ca/mr.187/photos.html)

According to record Zimmerman noticed
smoke at approximately 10,000m and 16
minutes later, the plane slammed into the
Atlantic Ocean off Peggys Cove, N.S.
Canada.
• According to Susan Bradley, a spokeswoman
for Boeing, Kapton was the primary coating
on the wiring in Swissair Flight 111 (Maclean’s Sept 21, 1998 v111 n38
p20(1))

How Safe is Kapton
Wiring
Picture taken from web site (www.ece.msstate.edu/hvl/research.html)

Patrick Price (Expert with the former Boeing Co. in
Seattle) on Kapton wiring
• “It’s like taking an incendiary bomb on board” (Maclean’s,
Sept 21, 1998 v111 n38 p20(1))

In 1982 the U.S. navy stopped using Kapton
wiring in jet fighters when cracks in wires coated
with Kapton were linked to on-board fires. (Maclean’s,
Sept 21, 1998 v111n38 p20(1))

Scientists have found Kapton is prone to rare but
catastrophic “arc tracking” when the wire is
subjected to chafing, vibration, and moisture. U.S. News
and World Report, Sept 28, 1998 v125 n12 p44(1))

If a wire cracks, electricity can arc to nearby
material, setting it on fire. This is known as a flash
over which burns at a searing 1,000 C.
Deadly Games



Swiss Air Flight 111 had approximately 240 km of
wires running through it to bring passengers a
premium video and gambling system in today’s
intensely competitive market for business and
first-class flyers.
Each seat aboard Swiss Air Flight 111 had a video
screen that pops out of the armrest like a tray
table. Passengers could play video games, music,
or even gamble.
• It was this luxury which could have lead to the
crash.
The system costs about 2 million or more dollars
per plane and was developed by Interactive Flight
TechnologiesTM. A struggling company which said
it wants out of the in-flight-entertainment
business.
• This web of wires from each seat to central
computers aboard the plane generates a
greater possibility for an electrical disaster. (Time,
Nov 9, 1998 p58(1))
Advanced Kapton
Material is Being Used
Today
 Since 1993 Kapton has been
improved by wrapping it in a
tough Teflon coating.
 In an article I found from 1998
FAA officials said that old forms
of Kapton may soon be removed
from hundreds of planes.
 Boeing company spokesman
John Thom said that “Kapton
was and is certified for use on
commercial airplanes”
(Maclean’s, Sept 21, 1998 v111 n38
p20(1))
Some Pictures from the
aftermath
Picture taken from web site (http://www3.ns.sympatico.ca/mr.187/photos.html)
 At left is one of the most
recognizable photos from the
tragedy as rescuers try in vain
to find survivors. Pictured at
right is the Emergency Service
Paying tribute to Flight 111
Fire Prevention in Planes
Picture taken from web page (http://www.airliners.net/open.file?id=13250)

The Federal Aviation Administration or FAA
announced in October of 1998 that Mylar
insulation used in nearly 12,000
passenger jets must be replaced to
reduced the chance of fire.
(U.S. News and World Report, Oct 26, 1998
p17(1))
• It is believed that this type of insulation was
set ablaze by a short circuit in the electrical
equipment aboard the Swiss Air Flight 111
Luxury is
not always
better
Picture from web site
(http://www.tsb.gc.ca/ENG/TSB_Investigations/Swissair/)

The high tech video system aboard Flight
111 used Microsoft Windows NT software,
with wires connected to a central
computer.
(Time, Nov 9,1998 p58(1))
• Investigators found that the wires had been
connected to the same electrical pathways
that powered vital parts of the aircraft.
– Therefore, if there is a problem with the video
system, then there is a problem with the whole
plane.

In the future this type of video system
should be connected to a separate area of
the plane where vital networks in the
plane will not be affected thus buying time
for an emergency landing.
Firefighting Training for
Pilots and Prevention
Web site (http.www.tsb.gc.ca/EN/TSB_Investigations/Swissair/site_pages/saf…/FireRecs_2000dec4.ht)

The investigation into Swiss Air Flight 111
revealed safety deficiencies in crew
training and awareness, and procedures
related to in-flight firefighting.
• The TBS safety board issued the following
recommendations to address safety
deficiencies
– A lack of a coordinated and comprehensive
approach to in-flight firefighting.
– Smoke/fire detection and suppression systems
are insufficient
– There are no smoke/fire detection and
suppression systems in the cockpit or cabin or
any area not considered a fire zone.
– The importance of making prompt preparations
for a possible emergency landing is currently
not recognized.
– This is due to company policy and the feeling
that it is an inconvenience.
– Access to critical areas within the aircraft are
inadequate.
– There has been little or no training provided to
aircraft crew on how to access areas behind
electrical or other panels
Material For Fire
Prevention

Halon
(Washington Monthly, Sep 1997 v29 n9 p44(2))
• Pressurized bottles of Halon – a highly
effective fire fighting agent – have long been
used in the cargo holds of larger jets but is not
used in smaller planes
– Brings us to the fact that in general the
larger the vehicle the safer it usually is due
to greater regulations.

A Plastic Called PHA
(Discover, August 1999 v20 i8 p11)
• PHA is a plastic which only emits water vapor when it
burns, and it brakes down into a flame-resistant
compound.

There is also the possibility of Flame
Retardant Material
(Class Notes)
• Chlorine and Fluorine when added to material
help in fire resistance.
– Trade off would be the hazardous smoke this
type of compound produces when it does burn.
– Flash overs due to electricity arcing burn at a
searing 1,000 C.
Crash Statistics
Larger The Vehicle the
Safer
 Some airline safety facts
(Web Site (http://www.air-
transport.org/public/speeches/view1997.asp?UniqueID=38))
• You are more likely to die by being
kicked to death by a donkey than
in a plane crash
• You are more likely to be crushed
by a falling object
• You are much more likely to be
killed by your spouse
 You have one chance in about 7
million from dying in an plane
crash
Average Time
To React
To A Fire
(http://www.nifc.gov/gallery/manter.html)

The average time between when an
in-flight fire is detected and when
the aircraft either ditches, conducts
a forced landing, or crashes is about
17 minutes.
(http://www.tsb.gc.ca/ENG/TSB_Investigations/Swissair/site_pages/saf…/FireRecs_2000dec4.ht)
• Some examples
Type
Date
Minutes
AN-12
B-707
B-747
MD-11
1967
1973
1987
1998
<10
~7
19
20
Increase Your Chances
 Handy Hints For The Nervous
Traveler
(http://www.amigoingdown.com)
• 70% of incidences in recent year
occur on take-off or landing
– Try to book non-stop flights
• Take note of where the nearest
emergency exit is
• Choose a large aircraft
– The larger the vehicle the better
your chances
Does Fate Alone Decide
Who Survives
Most Likely No
 71% of the people who die in crashes
die after the plane comes to a
compete stop.
 You can increase your chances by
knowing your surroundings

(People Weekly, Oct 20, 1997 v48 n16 p125(3))
• How many isles to the exit
• In case of fire if you can hold your
breath for 30 seconds that’s how long it
takes to exit the aircraft normally.
• Don’t try and get your duffel bag in case
of a crash
• Pay attention to the safety procedures
(life vests)
Where
To Sit
(http://www.aircrash.org/burnelli/)
 If you’re worried about impact
(People Weekly, Oct 20, 1997 v48 n16 p125(3))
• Sit in the back
 If you’re worried about a fuel
fire
• Sit forward of the leading edge of
the wing
 If your worried about the plane
breaking up
• Sit by the over-wing exits
– This is the strongest part of the
aircraft due to the fuel being
carried in the wings
Improved Electrical
Apparatus Insulation
Material

One way to improve Wiring in planes is to
use an improved insulation material
• Currently many electrical wires use
porcelain and glass insulators
• An ethylene and vinyl acetate
copolymer (EVA) tested better in the
lab these forms of insulation
(Polymer Engineering and
Science:Jul. 1996, V.S. Ivanov, I.I. Migunova, N.A. Kalinina, G.N. Aleksandrov)
– As discussed in class copolymers usually
increase a materials ability to withstand
an impact
– Copolymers would help in wires that would
be subjected to rough conditions
– Kapton currently has problems under
rough conditions
Radiation-Induced
Current
(ChemAbsStudent, “Studies on radiation-induced current in polymeric insulating materials
and their fine sturcture”, J. Master. Sci 17 no 10 (1982):3052-6)
 Degradation in crystalline
materials such as Polyethylene
 Degradation in non-crystalline
materials such as ethylenepropylene rubber used for wire
insulation
• For radiation-induced current
degradation is affected more by
the degree of crystallinity than
its perfection.
Method For Improving The
Environmental Stress-Crack
Resistance or (ESCR)
(J. Appl. Poym. Sci. 16, no 9 (1972): 2375-86)

(ESCR) is a critical factor in wire
insulation
• In studying the effect of rubber on
(ESCR) the choice of a base resin is
important
– Depending on the resin and rubber
combination you choose the (ESCR) can
double or increase by 50-fold.
– Kapton could be improved with slight
variations in its production and perhaps
different types of resins should be looked
at
• For example
– The higher the molecular weight of
Polyisobutylenes the more effective its
performance as a stress crack additive
Polymers – Good
Insulators
 Polymers are good insulators
because they are covalently
bonded and their electrons are
all tightly bound.
Polymers –
Conductors!?
Doping of polymers with strong
electron acceptors such as iodine
can cause polymers to conduct
nearly as well as metals.
 Doping to polyacetylene causes it’s
conductivity to be 1010 times higher
than pure polyacetalylene.
 This flexible electronic circuit
functions even when it’s bent.
 http://focus.aps.org/v6/st18.html

Uses of KAPTON Properties
Maintains its mechanical stability at
very high and very low temperatures
 resists high mechanical stress
during assembly operations
 has excellent electrical insulation
and thermal properties
 has outstanding resistance to most
chemicals, lubricants and fuels
 allows space and weight savings

Uses of KAPTON Electronics
In electronic equipment, KAPTON is
used as substrate material for
Flexible Printed Circuits and
punched, bonded or formed high
performance part in small miniature
switches. It can be etched in
alkaline solns.
 Bar Code Labels
 Heat Sinks, to ensure optimal heat
transfer between film and power
transistors
 Masking tapes

Uses of KAPTON Bondable Application
 Can be bonded, coated or
laminated to allow the
following requirements
•
•
•
•
•
Belts
Thermal insulator in irons
Fuel sensors
Smoke hoods
Blood bags
Uses of KAPTON Electronic Insulation
 Wire and cable insulation
 formed coil insulation of
traction motors
 Magnet wire insulation
 transformer and capacitor
insulation
Uses of KAPTON Automotive
 Alternator heat sink insulator
pads
 Air bag (diaphragm)
 Flexible circuits
 Spark plug boot
Uses of KAPTON Aerospace
 Cockpit sun shade
 Speakers
 Flexible Curcuitry
 Acoustic insulation
 Thermal blankets
Uses of KAPTON Thermal Management
 Heat sink
 Power supplies
 Heater circuits
 Copier belts
 Carrier belts
 Coil insulation
Thermal Degradation –
Experimental Methods
 Thermogravimetry (TG)-
measures loss in weight
 Differential scanning
calorimetry (DSC)
 Differential thermal analysisheat absorption or evolution
due to either physical or
chemical changes occurring
within the polymer is measured
Thermal Degradation
Reactions
 Depolymerisation Reactions
• Characterized by the breaking of
the main polymer chain
backbone so that at any
intermediate stage the products
are similar to the parent material
in the sense that the monomer
units are still distinguishable.
The ultimate product may be
monomer.
Thermal Degradation
Reactions
 Substituent Reactions
• It is the substituents attached to
the backbone of the polymer
molecules which are involved so
that the chemical nature of the
repeat unit is changed although
the chain structure may remain
intact.
Oxidation of Polymers
 Degradation of polymers
usually increases in the
presence of oxygen
 R· + O2  ROO·
 ROO· + RH  ROOH + R·
 Termination
• 2R·  R-R
• R· + ROO·  ROOR
• 2ROO·  ROOR + O2
Photo-degradation
Wavelengths of light from sun range
from infrared (>700nm) to the
visible spectrum (400-700nm) to
ultra-violet (<400nm).
 Energy of 700nm photon is 170
kJ/mol and energy of 300nm photon
is 390 kJ/mol
 Strength of C-C and C-H bond are 420
and 340 kJ/mol respectively
 It is clear that the energies of the UV
and possibly the visible
components of sunlight are
sufficient to break chemical bonds

Aircraft Crashes Due to
Failure in Wires
Short examples of Kapton
related crashed in aircraft
and what is being done to
prevent any further
mishaps
August 19,1980 Saudi
Arabian Airlines Tri-star
After take off from Riyadh Airport a
fire broke out in the rear cargo
compartment.
 Plane returned to Riyadh as flames
broke through the cabin floor and
filled the cabin with smoke
 Upon investigation Kapton wires
were found burnt out, and the
insulation destroyed
 Also the wires had fractured ends , a
sign of arcing, no other source for
ignition could be found

January 14, 1985 British
Monarch Airline Boeing
757
 On a flight from the Canary
Islands to Luton the aircraft has
a serious wire bundle explosion
 As smoke begins to enter the
cabin the pilot is able to make a
forced landing in Portugal
 An investigation showed that
moisture dripped onto the
wiring below the lavatory and
wet arc tracking occurred
causing the bundle explosion
November 5, 1990
Philippine Airlines
Boeing 737
 Plane is being delayed for take
off when explosion occurs
 The explosion was in the fuel
tank
 After investigation the most
probable cause was
determined to be a spark from a
faulty wire creating an
explosion
March 17, 1991 Delta
Airlines Lockheed Tristar
 Plane is on way to Atlanta from
Frankfurt when a fire breaks out
 Aircraft makes an emergency
landing in Goose Bay
 Upon an investigation the most
probable cause of the fire was
electrical arcing in the wire
bundle
Some Action Being
Taken
 Following a Valujet crash in
Florida in 1998 Al Gore has
headed a special commissin to
determine the ageing effects
on airplane wiring
 Other countries plan on doing a
similar thing
 However, the tests will be nonintrusive