1. Continuing analysis and surveillance system (CASS)
AIRCRAFT MAINTENANCE
Continuing analysis and surveillance system (CASS)
Reliability & Safety
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2. Reliability Definition
“The probability that an item will perform a required function, under specified conditions without failure, for a specified amount of time.”
2 Main Approaches
Looks at Whole Operation : Dispatch Reliability
Looks at Maintenance Program : Reliability Program
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3. Reliability Term Reliability Types of Reliability (4 types)
Overall Reliability
Component Reliability
Process Reliability
Maintenance Program Reliability
Types of Reliability (4 types)
Statistical Reliability
Historical Reliability
Event-oriented Reliability
Dispatch Reliability
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4. Reliability Event-oriented Reliability
Concerned with one-time events such as bird strikes, hard landing, in-flight shutdowns, or others accidents or incidents, which these are events that do not occur on a regular basis.
Each occurrence must be investigated to determine the cause and to prevent or reduce the possibility of recurrence of the problem.
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5. Reliability Dispatch Reliability (DR)
DR is a measure of the overall effectiveness of the airline operation with respect on-time departure. It is a simple calculation based on 100 flights.
DR involves more than just maintenance
Dispatch delays should look at the whole operation.
On-time departure means that the aircraft has been “pushed back” from the gate within 15 minutes of the scheduled departure time
Current-technology airplanes have a low incidence of technical airplane problems
affecting the flight schedule. A delayed flight, a canceled flight, an air-turnback, or
a diversion as a result of a technical maintenance problem does not occur very
often. (Note: In the aviation industry, a delay caused by a technical maintenance
problem must exceed 15 minutes from the planned revenue departure time to be
counted as a delay.) The reliability of the latest mechanical and avionics components
installed on airplanes has improved as a result of constant technical upgrades
to eliminate or reduce the frequency of failure modes. Consequently, the technology
incorporated into airplanes has continued to improve the reliability and safety of
the airplane. The Boeing 777 airplane has a schedule reliability of 99.12%, as
shown in Table This means that a Boeing 777 airplane will be delayed less
than 1% of the time as a result of technical maintenance problem. This schedule
reliability number relates to delays caused by a technical maintenance problem and
does not include delays due to weather, air traffic control, catering, fueling, baggage
handling or passenger loading. Maintainability has been designed into the latest
airplane models to allow for quicker troubleshooting of technical problems and
easier access to airplane components. The maintainability designed into the latest
airplane models allows maintenance technicians to rapidly resolve technical problems
and to successfully dispatch airplanes thereby achieving higher schedule reliability.
AIRCRAFT MAINTENANCE
Downloaded
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6. Reliability
Dispatch reliability
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7. Reliability Reliability Department
Responsibility of monitoring failure rates, removals of A/C systems and components to measure the effectiveness of the overall maintenance program
Data Collection
Preliminary Investigation
Issue Alert Notices
Monitor Results
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8. Reliability Reliability Program
A set of rules and practices for managing and controlling a maintenance program
Monitor the performance of the vehicles and their associated equipment and call attention to any need for corrective action
Monitor the effectiveness of corrective actions
Provide data to justify adjusting the maintenance intervals
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9. Reliability Elements of a Reliability Program Data collection
Problem area alerting
Data Display
Data analysis
Corrective actions
Follow-up analysis
Monthly report
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10. Reliability Data collection Flight time and cycle
Cancellations and delay over 15 minutes
Unscheduled component removals
Unscheduled engine removals
In-flight shutdowns of engines (IFSD)
Pilot reports or logbooks
Cabin logbook
Component failure (shop)
Maintenance check package findings
Critical failures
▪ Data collection ▪ Problem area alerting ▪ Data Display ▪ Data analysis ▪ Corrective actions ▪ Follow-up analysis ▪ Monthly report

11. Reliability Problem area alerting An alerting system
Identify those areas where the performance is significantly different from the normal
Alert level is based on a statistical analysis
Alert level is set at one to three standard deviations above the mean rate
Alert level is referred as UCL (Upper Control Limit)
Additional calculation that can be made to smooth the curve (3 months average) and help eliminate “false alerts”
▪ Data collection ▪ Problem area alerting ▪ Data Display ▪ Data analysis ▪ Corrective actions ▪ Follow-up analysis ▪ Monthly report

12. Reliability Problem area alerting (cond.) An alerting system
Air carriers used a failure rate alert program with upper control limits (UCL) and lower control limits (LCL) to track part failure rates.
Air carrier was obliged to take action only when the failure rate deviated from the probability-based prediction, i.e., exceeded the UCL or the LCL.
If the part did not respond, the air carrier was authorized to move the UCL or LCL to make the failure rate within the alert program limits.
▪ Data collection ▪ Problem area alerting ▪ Data Display ▪ Data analysis ▪ Corrective actions ▪ Follow-up analysis ▪ Monthly report

13. UCL (Upper Control Level)
Reliability
Problem area alerting (cond.)
Setting and adjusting alert levels
Recommended that alert levels be recalculated yearly
UCL (Upper Control Level)
3 months Offset
Control Chart
▪ Data collection ▪ Problem area alerting ▪ Data Display ▪ Data analysis ▪ Corrective actions ▪ Follow-up analysis ▪ Monthly report

14. Reliability Data analysis Reliability Department
a preliminary analysis to determine if the alert is valid
If valid, on-alert condition is sent to engineering for a more detailed analysis
Engineering Department
Troubleshoot the problem
Issue EO (Engineering Order)
Recommendations to the Airline Maintenance Program Review Board (MPRB)
▪ Data collection ▪ Problem area alerting ▪ Data Display ▪ Data analysis ▪ Corrective actions ▪ Follow-up analysis ▪ Monthly report

15. Reliability Corrective actions
Modifications of equipment
Correction to line, hangar or shop processes or practices
Disposal or defective parts
Training of mechanics
Addition of maintenance tasks to the program
Decreased in maintenance intervals
Completion of the corrective action is noted in the monthly reliability report
▪ Data collection ▪ Problem area alerting ▪ Data Display ▪ Data analysis ▪ Corrective actions ▪ Follow-up analysis ▪ Monthly report

16. Reliability Follow-up analysis
Verify the corrective action taken was indeed effective
Reflected in decreased event rates
If no significant change, corrective action should be reanalyzed
▪ Data collection ▪ Problem area alerting ▪ Data Display ▪ Data analysis ▪ Corrective actions ▪ Follow-up analysis ▪ Monthly report

17. Reliability Monthly report Working tool for maintenance management
Picture of what problems are encountered
▪ Data collection ▪ Problem area alerting ▪ Data Display ▪ Data analysis ▪ Corrective actions ▪ Follow-up analysis ▪ Monthly report

18. Reliability Reliability Program Document
Every aspect of the reliability must be documented in an official document signed be MPRB chairman and approved be the regulatory authority
Include:
Detailed discussion
Methods used to determine alert levels
Rules relative to changing
Define MPRB activities and Responsibility
Monthly Report Format
Submitted to FAA for approval
▪ Data collection ▪ Problem area alerting ▪ Data Display ▪ Data analysis ▪ Corrective actions ▪ Follow-up analysis ▪ Monthly report

19. Safety
Apr-17

20. Traditional Safety Management
Loss Control - Correction approach
Loss control is the tools for
- Prevention
- Reduction
- Elimination
Cause of incident and accident is
-Unsafe Action
-Unsafe Condition
Apr-17

21. Loss Causation Model
1. Loss - Loss of Direct cost - Loss of Indirect cost 2. Incident 3. Immediate Cause - Low standard action and Low standard condition 4. Basic Cause - Personal Factor and Job Factor 5. Lack of Control
Apr-17

22. Loss Control Management Process
Identification of Work
Set Standard
Measurement
Evaluation
Commendation and Correction
Apr-17

23. Modern Loss Management
1. Source of Loss - People - Equipment - Material - Enviroment 2. Loss Control systems - International Safety Rating System (ISRS) -US - Total Loss Control Management-UK
Apr-17

24. Modern Safety Management
Modern Safety Management – Prevention, Risk Assessment and Risk control approaches
Modern Safety Management is Loss Control Management
Modern Safety Management used POLC framework
Apr-17

25. Modern Safety Management
There are 4 approach to Modern Safety Management
1. Management concept
2. Management information system
3. Performance standard
4. Measurement and Evaluation system
Apr-17

26. System Safety
Apr-17

27. FAA - Safety Risk Matrix FAA Advisory Circular No
FAA - Safety Risk Matrix FAA Advisory Circular No , Introduction of Safety Management Systems for Air Operators
Apr-17

28. FAA - Safety Risk Matrix
Unacceptable (Red). Where combinations of severity and likelihood cause risk to fall into the red area, the risk would be assessed as unacceptable and further work would be required to design an intervention to eliminate that associated hazard or to control the factors that lead to higher risk likelihood or severity.
Acceptable (Green). Where the assessed risk falls into the green area, it may be accepted without further action. The objective in risk management should always be to reduce risk to as low as practicable regardless of whether or not the assessment shows that it can be accepted as is. This is a fundamental principle of continuous improvement.
Acceptable with Mitigation (Yellow). Where the risk assessment falls into the yellow area, the risk may be accepted under defined conditions of mitigation. An example of this situation would be an assessment of the impact of a non-operational aircraft component for inclusion on a (MEL). Defining an Operational (“O”) or Maintenance (“M”) procedure in the MEL would constitute a mitigating action that could make an otherwise unacceptable risk acceptable, as long as the defined procedure was implemented. These situations may also require continued special emphasis in the safety assurance function
Apr-17

29. General Safety Rules Fire prevention & protection
Hangar deluge systems
Fall prevention and Protection
Storage and handling
Smoking regulation
Hangar safety
Shop safety
Line safety
Apr-17

30. Hand Signal
Apr-17

31. Safety Management System
ICAO has established a framework for an SMS that incorporates four basic components and 12 elements as shown here:
Apr-17

32. MEDA Corrective Actions
Each contributing factor has a reasonable set of corrective actions. Many of the corrective actions were described in the dirty dozen. Corrective actions are often specific to the individual workplace and are best determined once the contributing factors are identified. Your event investigation practice during the classroom training will help you practice ways to identify corrective actions.

33. THE END