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Common Fleet Reliability Issues
Please click on any of the topics below to find out more information
ALERT PROGRAM TOPICS
 Coding
Rate Calculations
Assigning Alert Values
Non-Traditional Performance Monitoring
Technical Analysis Topics
The Initial Technical Analysis
Root Cause Analysis
Corrective Action
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AVIATION RELIABILITY SERVICES - FLEET RELIABILITY |
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Fleet Reliability - Assigning Alert Values
Alert values are developed to define an acceptable level of reliability. You choose how many pilot reports (Pireps) and/or flight delays and cancellations (D&Cs) you are willing to accept each month. If the monthly rate exceeds the alert level you have chosen, an alert notice is generated for the affected aircraft system.
There are several common ways to calculate and assign alert values. Most operators use a statistical approach (standard deviation, poisson distribution, rolling averages, etc). By using statistics alone, you run the very real risk of setting your alert values too high – and completely missing the start of a negative reliability trend. It is also entirely possible that you never even notice that performance has degraded – until the problem is widespread and severely impacting your operation. On the other hand, setting alert values too low creates an undue burden on your technical analysts – and wastes valuable time that could be spent working on more pressing issues.
Aviation Reliability Services recommends a graphical approach to setting alert values. By plotting monthly event rates (for each ATA on each separate fleet type) on a line graph, you can visually see the reliability trends for each separate aircraft system – and can compare the values and trends between fleet types. With a graphical approach, you will be able to set realistic alert values that are not too high or too low. This approach will also enable you to quickly readjust alert values as necessary (instead of the traditional once a year or once every other year recalculation).
It is also worth considering the safety and/or economic impact of aircraft system problems when assigning alert values. For example, a small number of brake system problems will have a much greater impact on your operation than a large number of broken coffee makers. The key is to prioritize the impact of failure. Safety always takes top priority. Economic impact is second. Convenience is a distant third.
In review, alert values are best assigned using graphical methods. Always consider the potential impact of reliability issues when developing your alert system.
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