Hello and welcome to SWENA's training.

In this class we will continue looking at

the
aircraft maintenance program and how airlines plan their maintenance activities. As
mentioned,
an aircraft maintenance program is a tailored maintenance plan the operator
prepares in order
to comply with the MPD and MRB requirements. However, there are certain
considerations they
must take into account. They are technical aspects as the operator must have the
available
resources to carry out its maintenance work. This can include operators
qualification and
certifications or technical and human resources. Commercial aspects such as local
air traffic
movement, seasonal demand and time of day. Operators may need to use their aircraft
more
intensely during holiday periods or at certain times of the day. They will need to
choose when
is more appropriate to carry out specific maintenance tasks. And finally,
operational
aspects. The duration and frequency of flights, location of its maintenance centers
and destinations
also influence their maintenance program. Some airlines may have long layovers at
certain
destinations for commercial reasons and may decide to carry out some maintenance
tasks with
local mechanics in the meantime. Remember, no two air carriers are the same and all
face
different challenges when planning their maintenance programs. Failure to consider
these
aspects can lead to an inefficient or impractical operation. Let's take a closer
look at the MPD,
the types of tasks it can contain and the codes used to refer to them.
Lubrication. Consumable replenishment by lubricating. Servicing. Consumable
replenishment by servicing. Operational check. A failure finding task to determine
if an item
is fulfilling its intended purposes and does not require quantitative tolerances.
Visual check.
A visual failure finding task through observation to determine if an item is
fulfilling its intended
purpose and does not require quantitative tolerances. General visual inspection. A
visual
examination that will detect obvious unsatisfactory conditions. Functional check. A
quantitative check
to determine if one or more functions of an item performs within specified limits.
This is a
potential failure finding task. Detailed inspection. An intensive visual
examination of a specific
detail, assembly or installation. This is a potential failure finding task. Special
detailed inspection. An intensive examination of a specific item, installation or
assembly
to detect damage, failure or irregularity. Restoration. Reworking, replacement of
parts
or cleaning necessary to return an item to a specific standard. Discard. The
removal
from service of an item at a specified time limit. Now let's see some examples of
the application
of the MPD and why it's important. Regarding the airframe structure, damage
prevention and repairs
are contemplated in the following types of tasks. Structural inspections which
outline tasks where
specific areas of the airframe are inspected for cracks. The supplemental
structural inspection
document that covers inspections for cracks that were not originally contemplated
in the SI document,
either because cracks were found in an unexpected area of the airframe, increased
crack risk due
to a structural modification or the aircraft is operated beyond its intended
operating cycles.
Airworthiness limitation items are maintenance and inspection instructions that
must be performed
at listed intervals and are adopted using the airworthiness directive process. They
are safety
critical actions that are needed to address unsafe conditions. And finally the
corrosion
prevention and control program, which outlines the tasks necessary to inspect
specific areas
of the airframe for corrosion damage and evaluate its degree of damage. In the case
of electric
and electronic systems, new task groups have had to be added to the MPD as the
development
of these systems implies ever more complex wiring systems present on aircraft. The
accumulation
of dust or dirt around these cables implies a fire hazard, so tasks included to
reduce these
risks in those areas include general visual inspections, detailed inspections and
restorations.
Civil aviation authorities sometimes emit advisory circulars outlining recommended
practices and processes and steps to implement electrical wiring interconnection
system inspections.
The MPD also instructs what tasks need to be performed on specific components. This
is a task to clean the primary and secondary heat exchanger. It states that the
procedure
must follow the steps detailed in the corresponding component maintenance manual.
All MPD tasks
must be completed at certain intervals, which can be measured in different ways. A
component
may need to be replaced after a certain calendar period or number of flight hours
and a task
may be required to be performed every time a major system is changed or the
aircraft
is under repair. Some of the different types of interval we may encounter are days,
airplane
flight cycles, airplane flight hours and months. Aircraft are large and complex
systems and
contain thousands of components, each with different requirements as to their
maintenance
and replacement. The MPD tells us what tasks must be performed and how often, but
only
so far. The operator must now prepare a maintenance program in order to comply with
the MPD.
In order to do this, maintenance tasks are usually grouped together in work
packages
so as to not interfere with the commercial operation of the aircraft. There are two
main
ways airlines group tasks. Block packaging, where many tasks are grouped into large
work
packages, resulting in less frequent but longer ground time. The advantages of
block
packaging are it reduces spare parts requirements at repair stations. Logistical
considerations
for spare parts are simplified. It allows for modifications to the aircraft to be
carried
out, the rectification of non-routine work. Finally, it permits a more efficient
sequencing
of long jobs. The disadvantages are increased manpower requirements, the risk of
the airplane
being cannibalized for parts, high component removal and increased ground time for
the
aircraft. The alternative to block packaging is equalized or phased packaging.
Maintenance
tasks are divided into smaller, more frequent packages, allowing for shorter
aircraft ground
time. Its advantages are it simplifies manpower planning, higher aircraft
availability, reduced
ground time. Frequent visits support full component life and it allows for a more
balanced
workload on small fleets. Its disadvantages are high spare part requirements at
outstations.
It implies an increase in production planning and scheduling workload. Careful
planning
is required due to the limited aircraft ground time. There is a limited time for
the accomplishment
of modifications. Short jobs are inherently inefficient and it provides a limited
time
to identify and rectify non-routine work. As you can see, no one philosophy is
superior
and each airline's operating environment will favor one or the other. In some
cases,
a combination of both is the best way forward. Let's take a closer look at the
reasons that
would lead an operator to choose one philosophy over the other. Block packaging is
usually
preferable when the operator has a larger fleet, a high aircraft utilization, spare
aircraft available, non-scheduled maintenance tasks, flexible manpower, long range
operations,
a single centrally located maintenance space, seasonal operating differences and
contracted
maintenance from third party repair stations. Equalized packaging would favor
airlines that
have a smaller fleet, low but constant aircraft utilization, no or few spare
aircraft, scheduled
operations, manpower equalization due to less human resources, short range
operations,
multiple maintenance locations and, maintenance is carried out at in-house repair
stations.
As mentioned, every aircraft contains thousands of different parts and systems,
each with
their own specific needs and maintenance intervals. Planning an adequate
maintenance
program that contemplates this is a complex task in itself and is only compounded
when
an airline has a fleet of many aircraft, sometimes from different manufacturers.
For this reason,
airlines must rely on an integrated maintenance planning software tool. These tools
allow
airline personnel to manage the technical data for their entire fleets and plan
their
maintenance programs accordingly. According to the ICAO, Continuing Airworthiness
Management
is defined as, all of the processes ensuring that, at any time in its life, an
airplane
complies with the technical conditions fixed to the issue of the Certificate of
Airworthiness
and is in a condition for safe operation. For operators based in EU nations and
others
who choose to follow EASA regulations, a Certified Continuing Airworthiness
Management organization,
commonly referred to as ECAMO, must be in place. This is an organization which, as
we
mentioned, must be approved and is responsible for the implementation of Continuing
Airworthiness
Management tasks. The role of ECAMO includes the development and compliance of the
maintenance
program, reliability program, airworthiness directive compliance, service bulletin
evaluation
and embodiment, test flights, coordinating defect rectification, and the
safekeeping
of accurate aircraft records. In today's aviation industry, services are
increasingly
being outsourced. From catering to maintenance to cabin crew, many airlines are
working towards
leaner operations by subcontracting previously in-house roles. Similarly, an
operator can
subcontract camo functions to an independent camo, which acts as an internal camo
would.
EASA also has the power to give a camo second privileges, though this isn't
necessarily
applied in all cases. These second privileges allow the camo to conduct
airworthiness review
on aircraft, issue or recommend for issue airworthiness review certificates, and
issue
permit to fly for maintenance check flights, responsibilities usually reserved for
the
Civil Aviation Authority. So, you now understand the complexities of an aircraft
maintenance
program, the interaction between each organization and the air carrier, and the
processes and
documents involved. That's it for this class. See you next time.