May/June 2023 - 26

WHEEL S AND BR AKES
The wheel is then inspected via non-destructive
testing (NDT) to see if there are any cracks or
damage to the wheels and boards. NDT inspection
includes magnetic particle inspection, eddy current
testing, and ultrasonic inspection. The latter, Fadili
notes, is new tech for AMETEK and they are in the
process of training employees to use it.
" This is something quite new to use ultrasonic
for wheels, " he said.
After NDT, the wheels are painted.
" We are applying first the primary paint and then
the final paint, and then going back to the shop for
reassembly and new tire. It's a quite simple, quite
lean process, " he continued.
Fadili said that the overhaul process is largely
the same for the brakes, outside of replacing tires.
Instead, the overhaul involves replacing the lining on
a steel brake, or the carbon impact for carbon brakes.
The overhaul cycle between tires, wheels and
brakes varies greatly. Fadili said they're often not
worked on all at the same time. The type of aircraft
plays a role. Large commercial jets will have a different
overhaul cycle than smaller counterparts.
In general, Fadili said wheels and tires are overhauled
every 200 to 400 cycles, with brakes between
1,200 to 200,000 cycles.
Wheels mostly wind up in need of repair due to
Non-destructive testing
is a crucial piece of
the overhaul process
for wheels, brakes
and landing gear.
AMETEK MRO
worn tires and brakes need repair because of leakage,
both are caused by normal wear and tear.
One factor that decreases the overhaul cycles is
weather. In warmer climates and during the summer
months, the wear on tires accelerates.
" Mostly during the summer season, we have
much more removals than during the winter season
because the temperature of the runway is much
higher and it really degrades, " he said.
Fadili said AMETEK prepares and stocks up for
the summer season because they know for sure
that during the European hot season of June, July,
August and September, tire removals increase 10
to 15% more than in the winter.
" We try to anticipate as much as we can. Of
course, we try to have as much as we can in stock
for the summer season. What we try to do is not
to have an average consumption or to work on an
average consumption all year, but really to increase
our needs for the summer season, " he said.
AMETEK doesn't see corrosion as a major cause
of concern, he said but for aircraft operating in
saltier regions, it can become a problem.
Landing Gear
While corrosion may not be of great concern for
wheels and brakes, Raul Cruz-Alvarez, CEO and
accountable manager, Landing Gear Technologies,
said it's enemy number one for landing gear.
" When I first started, it used to take one to two
days to remove a nut because of the amount of corrosion
that was on there, " he recounts.
Corrosion is such an issue due to a combination
of water and the drastic, rapid temperature changes
the landing gears experience. For example, using
Landing Gear Technologies' home base of Miami,
Florida, a plane can go from rainy, humid and 90
degrees Fahrenheit to 35,000 feet and minus 50
degrees in half an hour. And this process of extreme
changes will likely repeat multiple times a day.
That starts day one after a landing gear is
installed, Cruz-Alvarez notes.
" The first day you introduced the gear back on
the aircraft and you start rolling it around, the corrosion's
going to start setting in because of the differential
temperature. And, just the humidity in the
air. We always got to remember that air is a fluid
anywhere we look at it. For however small, there are
molecules of water in the air, " he said.
Nowadays, it no longer takes a couple days to
remove a nut because of corrosion, thanks to their
design and corrosion inhibitors, but the process
to overhaul landing gear remains work-intensive.
Broadly, landing gear will be overhauled every
eight to 12 years, depending on the aircraft, with
10 years being the average. The number of cycles
landing gear can see in that timeframe varies
26 MAY/JUNE 2023
AIRCRAFT MAINTENANCE TECHNOLOGY
May/June 2023

Table of Contents for the Digital Edition of May/June 2023
