Jetrader - September/October 2011 - 41

operation, which greatly contributed to the development of a comprehensive solution.

What is PdM and How Does it Work?
PdM is a proactive approach that essentially aims to prevent any kind of defect before an occurrence in the repair cycle. Success requires accurate data and an understanding of not only design from an engineering perspective but also the knowledge of experienced maintenance technicians.

A predictive approach transforms your strategy beyond maintenance to sustainment.
In the case of an avionics component, we learned that when we combined these two experiences with other line replaceable units, we were able to induce a failure when the test protocol could not replicate it. Our application of PdM on a component is now more likely to involve “deterioration prevention” and “maintenance reduction,” rather than swapping out the card. The use of PdM techniques helps determine the condition of in-service equipment in order to predict when maintenance should be performed. This approach offers cost savings over traditional or time-based preventative maintenance because tasks are performed only when warranted. The concept of soft timing for preventative maintenance is not new to the airline environment. Airframes, engines and systems components routinely are inspected and repaired based on the RCM (reliability-centered maintenance) and PdM models. To be successful in applying preventative maintenance to components, we needed commitment to PdM principles from the leadership of both the airline and the OEM. As we combined efforts, both teams’ cultures underwent a transformation with a shared belief in:

1. A business culture designed to continuously improve the efficiency of the unit. 2. A standardized and systematic approach to identify and prevent all losses. 3. All departments infl uencing the design and repair of a unit participate in moving from a reactive to a predictive maintenance mindset. 4. A transparent multidisciplinary organization must strive for zero defects in the total unit versus just finding and fi xing one problem at a time. 5. Continual improvement steps are taken as a journey, not as a quick visit. An important element of PdM is ongoing evaluation of the condition of equipment through periodic or continuous (online) equipment condition monitoring. The “predictive” component of this maintenance stems from the goal of predicting the future trend of the equipment’s condition. This approach uses principles of statistical process control along with a thorough understanding of the operating system from a technician’s perspective to determine at what point in the future maintenance activities will be appropriate.

new simulation, it failed just like it did on the aircraft. This process was replicated and validated at the OEM facility with the same result. The OEM had us remove selected chips for further destructive testing, which identified the failure of the circuit as moisture entering the protective coating of a microchip. A discussion with the chip manufacture and the OEM design team revealed that the initial test for the chip indicated a life cycle of about 10-12 years, which was about the time we began to experience the problem.

PdM Offers Significant and Sustainable Improvement
The key difference between RCM and PdM is that RCM is a maintenance improvement strategy whereas PdM recognizes that the maintenance function is reactionary to a condition. You must address the condition in order to have significant and sustainable improvement of reliability and lowered costs. Adoption of these methodologies can result in substantial cost savings and higher system reliability. On this unit alone we saw, within six months, a 34 percent improvement of all unscheduled removals (85 removals), 100 percent improvement on identifying potential faults of what is currently NFF removals and finally, the significant MTBUR increase. Patrick Doyle is the senior manager, Aircraft Maintenance, FedEx Express. This is part one of a two-part series on predictive maintenance in aging aircraft systems. Part two will be published in the November/December issue of Jetrader.

How We Applied PdM
Traditionally, inspections and tests are performed while the equipment is in a controlled environment of a shop. This setting does not normally consider the age of the unit, nor the factors that infl uence degradation of the units while in its operating environment, such as vibration, pressure and temperature changes. For a true understanding of what the unit is doing, we require details on not only the failure condition that drove the unit to the shop, but also on its operating environment. In our case, to establish the circuit’s condition, the airline team used the BITE information combined with the technician’s recommendations to simulate the operating environment by heating and cold soaking the unit. With engineering approval on these simulations, we dove in. On the first test under these conditions, when the unit was subject to this

References
Nakajima, Seiichi (1989). Introduction to TPM. Cambridge, Mass.: Productivity Press. Hartmann, Edward George (1992). Successfully Installing TPM in a Non-Japanese Plant: Total Productive Maintenance. TPM Press. ISBN 1882258002. Nakajima, Seiichi (1989). TPM development program: implementing total productive maintenance. Cambridge, Mass.: Productivity Press. ISBN 0-915299-37-2. Jetrader 41



Jetrader - September/October 2011

Table of Contents for the Digital Edition of Jetrader - September/October 2011

A Message from the President
Calendar/News
Q&A: Henri Courpron
State of the Regions: Europe
Paris Air Show Review
Thank You Sponsors
All About Growth
Predictive Maintenance in Aging Aircraft Systems
Have Faith
Parts on Demand
Culture of Accountability
Aircraft Appraisals
From the ISTAT Foundation
Aviation History
Advertiser.com / Advertiser Index
Jetrader - September/October 2011 - Cover1
Jetrader - September/October 2011 - cover2
Jetrader - September/October 2011 - 3
Jetrader - September/October 2011 - 4
Jetrader - September/October 2011 - A Message from the President
Jetrader - September/October 2011 - 6
Jetrader - September/October 2011 - 7
Jetrader - September/October 2011 - 8
Jetrader - September/October 2011 - Calendar/News
Jetrader - September/October 2011 - 10
Jetrader - September/October 2011 - Q&A: Henri Courpron
Jetrader - September/October 2011 - 12
Jetrader - September/October 2011 - 13
Jetrader - September/October 2011 - 14
Jetrader - September/October 2011 - 15
Jetrader - September/October 2011 - 16
Jetrader - September/October 2011 - 17
Jetrader - September/October 2011 - State of the Regions: Europe
Jetrader - September/October 2011 - 19
Jetrader - September/October 2011 - 20
Jetrader - September/October 2011 - 21
Jetrader - September/October 2011 - 22
Jetrader - September/October 2011 - 23
Jetrader - September/October 2011 - Paris Air Show Review
Jetrader - September/October 2011 - 25
Jetrader - September/October 2011 - 26
Jetrader - September/October 2011 - 27
Jetrader - September/October 2011 - 28
Jetrader - September/October 2011 - 29
Jetrader - September/October 2011 - 30
Jetrader - September/October 2011 - 31
Jetrader - September/October 2011 - 32
Jetrader - September/October 2011 - Thank You Sponsors
Jetrader - September/October 2011 - All About Growth
Jetrader - September/October 2011 - 35
Jetrader - September/October 2011 - 36
Jetrader - September/October 2011 - 37
Jetrader - September/October 2011 - Predictive Maintenance in Aging Aircraft Systems
Jetrader - September/October 2011 - 39
Jetrader - September/October 2011 - 40
Jetrader - September/October 2011 - 41
Jetrader - September/October 2011 - 42
Jetrader - September/October 2011 - Have Faith
Jetrader - September/October 2011 - 44
Jetrader - September/October 2011 - Parts on Demand
Jetrader - September/October 2011 - 46
Jetrader - September/October 2011 - Culture of Accountability
Jetrader - September/October 2011 - 48
Jetrader - September/October 2011 - Aircraft Appraisals
Jetrader - September/October 2011 - 50
Jetrader - September/October 2011 - 51
Jetrader - September/October 2011 - 52
Jetrader - September/October 2011 - From the ISTAT Foundation
Jetrader - September/October 2011 - Aviation History
Jetrader - September/October 2011 - 55
Jetrader - September/October 2011 - 56
Jetrader - September/October 2011 - Advertiser.com / Advertiser Index
Jetrader - September/October 2011 - 58
Jetrader - September/October 2011 - cover3
Jetrader - September/October 2011 - cover4
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