Types of Error in Maintenance Tasks
Form of Errors in aircraft maintenance engineering:
1. Error that results in a specific aircraft problem that was not there before the
maintenance task was initiated;
1. Error that results in a specific aircraft problem that was not there before the
maintenance task was initiated;
incorrect installation of linereplaceable units, failure to remove a protective cap from a hydraulic line before reassembly
or damaging an air duct used as a foothold while gaining access to perform
a task.
2. Error that results in an unwanted or unsafe condition remaining undetected
while performing a maintenance task designed to detect aircraft problems, i.e. something is missed. -a structural crack unnoticed during a visual inspection task or a faulty avionics box that remains on the aircraft because incorrect
diagnosis of the problem led to removal of the wrong box.
Errors During Regular and Less Frequent Maintenance Tasks
or damaging an air duct used as a foothold while gaining access to perform
a task.
2. Error that results in an unwanted or unsafe condition remaining undetected
while performing a maintenance task designed to detect aircraft problems, i.e. something is missed. -a structural crack unnoticed during a visual inspection task or a faulty avionics box that remains on the aircraft because incorrect
diagnosis of the problem led to removal of the wrong box.
Errors During Regular and Less Frequent Maintenance Tasks
Errors During Regular Task - A large proportion of maintenance tasks are fairly routine, such as regular, periodic
checks on aircraft. Thus, engineers will use a certain set of procedures relatively
frequently and, slips and lapses can occur when
carrying out procedures in the busy hangar or line environment.
“Repetitive Tasks” - engineers will often become so accustomed to doing
a regular, often repeated task, that they will dispense with written guidance
altogether. It would be unrealistic and unnecessarily time consuming to expect them
to constantly refer to familiar guidance material. However, errors may occur if they do
not keep up-to-date with any changes that occur to these frequently used procedures.
These routine tasks are also prone to complacency, environmental capture and
rule-based errors.
Less Frequent Maintenance Tasks When undertaking less frequently performed tasks, there is the possibility of errors
of judgement. If the engineer does not familiarise or refamiliarise himself properly
with what needs to be done, he may mistakenly select the wrong procedure or parts.
Violation in Aircraft Maintenance
Four types of violations:
Routine violations are things which have become ‘the normal way of doing
something’ within the person’s work group (e.g. a maintenance team). They can
become routine for a number of reasons: engineers may believe that procedures may
be over prescriptive and violate them to simplify a task (cutting corners), to save time
and effort.
Situational violations occur due to the particular factors that exist at the time, such as time pressure, high workload, unworkable procedures, inadequate tooling, poor
working conditions. These occur often when, in order to get the job done, engineers
consider that a procedure cannot be followed.
Optimising violations involve breaking the rules for ‘kicks’. These are often quite unrelated to the actual task. The person just uses the opportunity to satisfy a personal need.
Exceptional violations are typified by particular tasks or operating circumstances that make violations inevitable, no matter how well intentioned the engineer might be.
Time pressure and high workload increase the likelihood of all types of violations
occurring. People weigh up the perceived risks against the perceived benefits,
unfortunately the actual risks can be much higher.
Where procedures allow some leeway, AME often develop their own strategies or preferred way of carrying out a task. Often, a ‘good’ rule or principle is one that has been used successfully in the past. These good rules become ‘rules of thumb’ that an engineer might adopt for day-to-day use. Problems occur when the rule or principle is wrongly applied.
Four types of violations:
Routine violations are things which have become ‘the normal way of doing
something’ within the person’s work group (e.g. a maintenance team). They can
become routine for a number of reasons: engineers may believe that procedures may
be over prescriptive and violate them to simplify a task (cutting corners), to save time
and effort.
Situational violations occur due to the particular factors that exist at the time, such as time pressure, high workload, unworkable procedures, inadequate tooling, poor
working conditions. These occur often when, in order to get the job done, engineers
consider that a procedure cannot be followed.
Optimising violations involve breaking the rules for ‘kicks’. These are often quite unrelated to the actual task. The person just uses the opportunity to satisfy a personal need.
Exceptional violations are typified by particular tasks or operating circumstances that make violations inevitable, no matter how well intentioned the engineer might be.
Time pressure and high workload increase the likelihood of all types of violations
occurring. People weigh up the perceived risks against the perceived benefits,
unfortunately the actual risks can be much higher.
Where procedures allow some leeway, AME often develop their own strategies or preferred way of carrying out a task. Often, a ‘good’ rule or principle is one that has been used successfully in the past. These good rules become ‘rules of thumb’ that an engineer might adopt for day-to-day use. Problems occur when the rule or principle is wrongly applied.