Airframe painting: the future`s bright the future`s

The leading international magazine for the manufacturing and MRO sectors of commercial aviation
A COLOURFUL FUTURE:
AIRFRAME PAINTING TRENDS
n OKLAHOMA’S UNIQUE AEROSPACE INDUSTRY
n THE BIOFUEL IMPLEMENTATION CHALLENGE
n CMO: BOEING’S NEW RFID-BASED SOLUTION
n TURBOPROP ENGINE MAINTENANCE MARKET
June - July 2011 Issue: 112
www.ubmaviationnews.com
ENGINEERING & MAINTENANCE
photo ©: Patrick Delapierre
Airframe painting: the
future’s bright, the future’s…
multicolour
Aircraft exterior surfaces impact on both corporate branding and operational reliability. Joanne Perry
spoke to paints/coatings manufacturers, refinishers and an MRO provider to find out about the latest
changes to airframe painting, including basecoat-clearcoat and chromate-free technology.
hen British Airways (BA) rebranded its
aircraft in 1996, dropping its iconic
Union Flag tailfins in favour of multicultural designs, the airline spectacularly failed
to predict the impact of its change in livery.
Critics alleged that the revamped tailfins were
both unpatriotic and difficult to identify. Given
the cost of the rebranding and BA’s subsequent
U-turn, it was scant consolation for the airline
that the vibrant new designs had been beautifully executed.
Beyond perceptual considerations, exterior
paint is important for operational reasons, as it
protects airframes from corrosion which might
compromise structural integrity. In performing
W
44 ❙ Aircraft Technology - Issue 112 ❙
this vital function, the paint must withstand
thermal stress, inclement weather, high-speed
particulate matter and chemicals such as fuel,
hydraulic fluid, oil and cleaning products. The
intensity of these stressors varies across the
airframe; for example, areas in close proximity
to the engines need to withstand especially
high temperatures. Furthermore, the painted
surfaces of moving parts such as wing flaps
and fairings, together with adjacent sections of
the fuselage, must endure additional friction.
The painting process
OEMs, refinishing specialists and MROs
conduct the airframe painting process accord-
ENGINEERING & MAINTENANCE
Top: A worker prepares an airframe for
painting.
Above: Sealants and fillers are applied to give
a smooth surface.
46 ❙ Aircraft Technology - Issue 112 ❙
ing to four key phases: stripping; surface preparation; painting; and livery detailing. Rod
Friese, president of Associated Painters, which
has bases in Washington, Oklahoma, Arizona
and Florida, says all stages have their challenges: “Stripping is a dirty job, preparing the
surface for paint is physically demanding, painting is meticulous and precise and detailing is a
blend of knowledge and creativity”.
As with any paint job, groundwork is the key.
When it comes to aircraft, this means “the
quality of surface preparation; surface reactivation, masking and degreasing”, according to
Bjorn Basjes, deco production manager at KLM
Engineering and Maintenance (KLM E&M).
Surfaces which must be protected from the
stripping agent, such as windows, composite
panels, antennas and landing gears, are
masked off before the stripper is applied once
or several times to the aluminium fuselage and
tail. The stripping chemicals are then neutralised and washed away using an alkaline
solution, fully revealing the condition of the airframe.
Composite surfaces must be prepared differently. Although they bring the advantage of
corrosion resistance, they can be damaged by
stripping agents and are prepared by mechanical sanding. The sanding takes off the finish
and minor defects, leaving a bare surface which
may require filler primers to regain smoothness.
The sanding can be intensive; on composite
materials Basjes reports “the frequent presence of paint cracking down to the substrate”,
necessitating full reworking. Indeed, MROs witness a significant worker injury rate during the
sanding process, mostly owing to physical
strain. Solutions to the problem are limited,
although one company in the US offers a fully
pneumatic, “easily manipulated mechanical
arm” (EMMA). This tool was launched in 2004
and has been deployed with some success at
commercial manufacturing (Boeing, Spirit,
Vought) and defence maintenance (Northrop
Grumman, Air Force) facilities. The manufacturer, Temple Allen Industries, claims that work-
ENGINEERING & MAINTENANCE
ers using the tool can increase their productivity four-fold or more while conserving their own
energy, avoiding injury and improving technical
proficiency. Robert Kent, industry relations
director at Temple Allen Industries, sees big
potential for EMMA as airframe manufacturing
evolves: “The trend towards composites
means that more and more manufacturing and
maintenance surface prep work will rely on
abrasives. EMMA is simply the most affordable
way for a facility to transition to sanding on a
large scale.”
EMMA is, however, likely to end up competing with new products devised by chemical
manufacturers. The creation of a stripping technology which removes paint yet leaves resins
unfettered may be “a challenge that we have
not seen met to date” according Friese, but he
is confident “that methods will change”. Rick
Smith, VP business development at Dean
Baldwin Painting, which has bases in Texas and
New Mexico, agrees that “paint and chemical
manufacturers are very adept at modifying their
products and processes to the needs of the
industry”. Furthermore, selective stripping
which targets superficial layers is gradually
being introduced.
Some degree of power abrading is also
used on conventional airframes, followed by
alkaline washing to create a “water break free”
surface indicating optimum cleanness — no
beading or patterning of liquid.
The next step in the process is to replace
seam sealants using products supplied by
manufacturers such as PPG Aerospace and USbased Advanced Chemistry and Technology (AC
Tech). PPG offers an impressively broad range
of sealants which are qualified for use on any
aircraft. AC Tech, meanwhile, is in the process
of being acquired by the diversified technology
giant 3M, as announced on June 10 this year,
with final integration due in 3Q, 2011. AC Tech
makes sealants for joint sealing and aerodynamic smoothing, alongside pre-treatments for
both composite and metal surfaces. The company prides itself on supplying reduced solvent
or solvent-free products; as well as delivering
environmental benefits, solvent-free products
reduce shrinkage and pin-hole effects from curing which adversely affect the paint job, possibly requiring the work to be redone.
AC Tech says the increased use of composites by airframe manufacturers will impact
sealant manufacturers in terms of performance
The “easily manipulated mechanical arm”
(EMMA) from Temple Allen Industries.
❙ Aircraft Technology - Issue 112 ❙
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ENGINEERING & MAINTENANCE
ufacturing material, wing structures subjected
to movement-induced friction are protected
with polytetrafluorethylene (Teflon).
The aircraft is then re-masked prior to the
application of a primer and top coats; custom details are added by means of masking
and stencilling techniques. An extra, transparent coat is applied to areas at high risk of
erosion such as the leading edge of the vertical stabiliser, the cockpit window surrounds
and the engine cowl inlet rings. Traditionally,
the final touch is to add the maintenance
placards and emergency exit bands required
by regulation.
Introducing a new palette
Top: Complex liveries are now easier to create
as a result of basecoat-clearcoat technology.
Above: A masked wing and nacelle.
48 ❙ Aircraft Technology - Issue 112 ❙
and compatibility issues, ultimately driving the
introduction of new sealants. Indeed, PPG
reports that its latest generation of lightweight
sealants have demonstrated excellent compatibility with composite structures.
The aluminium surfaces of the aircraft are
next subjected to a chemical conversion pretreatment to improve adhesion and corrosion
resistance. Composites need primers with different adhesive properties. They also require
anti-static coating, which is especially important for the radome containing the aircraft’s
vital radar equipment. The radome is not, however, the only area of the airframe which is
given special attention; regardless of the man-
Perhaps the biggest change in aircraft exterior painting in the last few years has been the
introduction of basecoat-clearcoat technology,
whereby all colours are applied as a basecoat
below a clearcoat finish. This technique, which is
compatible with composite airframes, delivers
time, product, maintenance, weight and environmental savings alongside enhanced aesthetics
including greater colour intensity, a higher gloss
finish and special effects such as pearlescence.
Basecoat-clearcoat development was driven by
Airbus, which in 2000 launched an investigation
into how the technology might be transferred
from the automotive industry. Paint manufacturer Mankiewicz, which is headquartered in
Germany, took up the challenge and conducted
ENGINEERING & MAINTENANCE
seven years of research and testing before
launching the new technology onto the aviation
market, gaining approval from Airbus in 2007.
Mankiewicz basecoat-clearcoat paint is on
the AMS-3095 qualified product listing (QPL) for
BAe Aerospace, ATR and Airbus, with Boeing,
Bombardier, Embraer and Saab currently evaluating the product for their own application and
approval. It is approved for all Airbus and Boeing
MRO aircraft. Other manufacturers are currently
working with OEMs to gain approval.
Basecoat-clearcoat products allow hours,
even days, to be shaved off the painting
process owing to the fact that the paint dries
more quickly, and requires only one coat as well
as minimal sanding or heating. Andreas
Ossenkopf, director, head of aviation, at
Mankiewicz says that the company’s basecoatclearcoat products generate savings of one or
two days, about the same as PPG, while USbased Sherwin-Williams gives a time reduction
of around 30 per cent — or 17 hours for a narrowbody aircraft (i.e. a painting time of 40
hours versus 57). AkzoNobel reports MROs
saving as much as 40 per cent of time spent
on exteriors featuring four colours, albeit based
on 24-hour shifts.
Time savings for basecoat-clearcoat products extend from the immediate to the longterm, as they enable the stretching of
maintenance schedules; greater durability
means the aircraft need to be repainted less
often. A spokesperson for PPG sees this
characteristic as “the primary advantage”. In
particular, the application of the clearcoat
over decals and stencils helps to protect
them from erosion, as well as resulting in
better laminar airflow. The spokesperson
says that with basecoat-clearcoat, airlines
can achieve a nine to 12-year coating lifecycle compared with the standard six years.
Indeed, a Mankiewicz/Qantas Airways monitoring programme involving A330 aircraft has
detected no visible deterioration in colour,
gloss or adhesion after 3.5 years of flying
time. The gloss, for example, retains a value
of 96/100 units in comparison with 92/100
for conventional coats. AkzoNobel cites
cases of 90/100 gloss levels even after a
decade of service under the intense atmospheric UV light conditions encountered during flight.
PPG’s representative explains: “The opportunities to garner advantage from reduced
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❙ Aircraft Technology - Issue 112 ❙
49
ENGINEERING & MAINTENANCE
A Qantas A380 showing the glossy finish
provided by Mankiewicz paint.
cycle time are greater with complex liveries and
for painting facilities that run 24-hour operations.” AFI KLM E&M is one MRO which
vouches that basecoat-clearcoat technology
“becomes interesting when the number of topcoats of the livery increases”. Basjes says that
while KLM already uses basecoat-clearcoat —
it was in fact the first airline to do so — the
simpler livery of Air France means that its use
for this airline is still under consideration.
The single-coat application of basecoatclearcoat, which contributes significantly to
time savings, also has the effect of lowering
the aircraft’s weight. This has important implications for airborne efficiency and emissions
as well as providing a cost benefit from the
decrease in product usage. Reduced amounts
of paint and solvents also lower the volume of
volatile organic compounds (VOCs) released
into the environment. Adding to the environmental and financial benefits, the lack of a
need to speed up the drying by heating reduces
energy consumption and CO2 emissions.
Furthermore, the tight film of the clearcoat
reduces cleaning efforts, with knock-on effects
for maintenance costs and waste disposal.
Currently there are some differences of
opinion over the impact of basecoat-clearcoat
technology on the existing paint market. One
would expect a product offering all the practical, financial and environmental advantages
described above to cause a drop in sales of traditional varieties. Mankiewicz has already
observed the beginning of this effect, “as both
the airlines and the MROs begin to see all the
advantages,” states Ossenkopf. AkzoNobel
and Sherwin-Williams, meanwhile, say that
demand for conventional paints remains
strong; PPG in fact reports an increase over the
last few years.
The difference is probably attributable to
length of pedigree, Mankiewicz being the pioneer, with a track record of more than 250
basecoat-clearcoat jobs completed thus far. As
Andrew Richardson, global market director at
AkzoNobel, explains, basecoat-clearcoat systems “are relatively new and not yet fully
approved by all OEMs”. He also points out that
certain products in the marketplace have not
performed to the potential of the technology,
which “makes people nervous”. Smith agrees
that “as the manufacturers improve their
basecoat-clearcoat products and they become
more widely accepted, increased demand for
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50 ❙ Aircraft Technology - Issue 112 ❙
ENGINEERING & MAINTENANCE
their use will follow”. PPG’s representative is
confident that basecoat-clearcoat and conventional paints can occupy different niches in the
same market on an indefinite basis, citing evidence from other industries which have known
basecoat-clearcoat for more than three decades
“and still require the use of both technologies”.
Chromate-free products
Another avenue of change for the painting
and coating business is the reduced chromate
or chromate-free product market, which has
arisen from health and environmental concerns. The trend toward non-chromate alternatives has been slower in the US than in other
developed markets. In Richardson’s opinion,
Europe leads the way with respect to chromatefree products. “Major European OEMs have
One of two Jazz Aviation aircraft painted with
PPG’s new green coatings system.
been using chrome-free exterior primer for a
number of years (albeit over a detail chrome
primer) and the MRO market has had lower
chrome products for around 20 years. We have
not seen that in the USA,” he says. Ossenkopf
has noted a similar “scepticism” in the US
among airlines and OEMs but says this is
falling away as aircraft bearing chromate-free
products continue to operate without problems.
Indeed, AC Tech predicts an accelerated migration away from chromate surface treatments.
Dean Baldwin Painting reports that chromate-free products are matching the performance of their predecessors. AC Tech says the
sol-gel technology it supplies enhances corrosion resistance by improving adhesion, eliminating inter-coat delamination and the selective
peeling known as “rivet rash”. Basjes, meanwhile, notes that trials have demonstrated no
greater corrosion with chromate-free products
than conventional primers. He points out that
an array of chromate-free products on the market are still awaiting approval because paint
scheme specifications are “extremely severe”,
although approval can be expected in the short
to medium term.
PPG claims that its new chromate-free technology exceeds the capabilities of traditional
products. In April this year, the company
became the first to have a chromate-free primer
qualified by Boeing. At the time, Kevin Brooks,
PPG Aerospace global segment manager for
original equipment coatings, commented that
the epoxy primer “achieves exceptional corrosion resistance” as well as reducing environmental problems and waste removal costs.
Together with a chromate-free pre-treatment and
topcoat, the primer was used in May this year to
repaint two regional aircraft for Jazz Aviation,
PPG’s first commercial aviation customer in
Canada for its new green coatings system.
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A colourful future
and money — imagine
An upturn in demand for the maintenance
services which airlines put on hold during the
recession has encouraged providers of paints
and painting services to expand and enhance
their capabilities. Mankiewicz, for instance, transferred its US operations from Missouri to new
facilities in South Carolina at the beginning of the
year, with plans to grow its capabilities there still
further over the next two or three years.
Among refinishers, Associated Painters
opened two new facilities in Washington and
Florida in October, 2010, and April, 2011,
respectively. Meanwhile, Dean Baldwin Painting
is developing a new facility in Indiana, with a
planned launch in the first quarter of 2012.
Also in the US, Leading Edge last year
expanded its operations in Texas, where it will
paint all new 787 Dreamliners. The company
additionally won a contract to repaint 350 of
the 1,250 aircraft in the newly merged United
Continental fleet and recently opened another
hangar in California to handle the extra work.
On an worldwide scale, it is generally agreed
that the booming economies of Asia, and in
particular China, represent the biggest growth
prospect for suppliers of paints, coatings and
refinishing services — a familiar story to anyone involved in the aviation industry. For example, PPG opened a support centre in Tianjin in
November, while Mankiewicz will unveil a new
base in Shanghai this September.
In the traditional markets, the recent mergers of airlines such as United and Continental
and BA and Iberia provide lucrative opportunities for companies involved in implementing livery changes. As the BA-Iberia amalgam,
International Airlines Group (IAG), prepares for a
rebranding programme later in 2011, it can only
be hoped that BA has learned its lesson from
the 1996 misfire. The products and providers
■
are out there — IAG must choose wisely.
being able to cut as much
as 30% from your painting
process time — and eliminating
most bake cycles. Plus, it
still provides the superior
appearance and durability that
the aviation industry expects
from Sherwin-Williams.
www.swaerospace.com
ASK
❙ Aircraft Technology - Issue 112 ❙
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