IN TIME

ubriik
Air Maintenance
Estonia specializes in
maintaining aircraft brakes.
Aviation is also one of the most regulated fields
of activity. When just one precept or rule is not
met the plane must stay on the ground.
The maintenance process in fact goes on all the
time – even during the flight when the operation
of the plane is monitored. Pilots check the temperature
and pressure of fluids as well as the voltage,
power consumption and the temperature of
air and exhaust gases, etc. After every flight all the
performance indicators are analysed and in the
case of abnormal deviation the plane is grounded
until the reason is found and the fault dealt with.
Of course, not all the problems can be detected
with monitoring and, therefore, regular checks are
carried out that are divided into different levels
and as prescribed by the manufacturer.
The levels of maintenance
The following applies to the Boeing 737.
Every night, these planes undergo an inspection
called Daily Check which takes approximately
one hour for a technician.
Every other day, planes go through a more thorough
Service Check, during which the fluid and
coolant supplies are checked and if necessary,
topped up. The Service Check manual has 17
pages referring to several other instructions and
checklists.
Every 250 flight hours (approximately once a
month) an A-Check is carried out that takes about
80 hours and includes general functional checks,
lubrication of certain assemblies, etc.
Every 4000 flight hours a C-Check is carried
out (in case of some aircraft types a B-Check is
also carried out before that) during which the
main structures of the plane are checked and general
repair works, as well as thorough functional
checks, are carried out.
Every 24,000 flight hours a D-Check is carried
out during which the plane is taken more or less
apart and its main structures is thoroughly inspected.
Plane parts
fall into three
categories:
1. Life-limited parts that need
to be replaced after certain
time, e.g. 25 years.
2. Service-limited parts that need
to be replaced after a certain
number of flight hours or after
a certain amount of time has
passed.
3. On condition parts that need to
be monitored regularly and
replaced whenever necessary.
Generally, plane parts are not
repaired. In case of a fault, a new
part is installed which, of course,
makes airplane maintenance more
expensive but when human lives
are at stake money is not an issue.
All of the air-carriers in the European
Union must abide by common
rules and requirements to ensure
that air-travel is a safe way of
travelling.
A cockpit is full of lights
and sensors that monitor the
operation of the plane.
32
INTIME I suvi/summer 2011