Reliability HotWire: eMagazine for the Reliability Professional
In this issue:

Issue 15, May 2002

*Hot Topics
*Reliability Basics
*Tool Tips
*Hot News
*From the Edge
*Share Your Experience

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Hot Topics  
The Generalized Gamma Distribution and Reliability Analysis
The Weibull life distribution has long been used for most life data analysis problems. The main reason for the distribution's popularity is the versatility it provides, i.e. the Weibull distribution can take on the characteristics of other types of distributions, based on the value of the shape parameter, beta. The generalized gamma distribution is also a flexible distribution, and in fact contains the exponential, Weibull, lognormal and gamma distributions as special cases. ReliaSoft's Weibull++ 6 software also includes a Generalized Gamma distribution option (when used in the Expert mode). We will use this article to explore the generalized gamma distribution and its relation to other lifetime distributions.

To read more, see 

Reliability Basics  
The purpose of this section is to offer background and advice to the novice reliability engineer.

Location Parameter of the Weibull Distribution
In last month's issue of Reliability HotWire, we had a detailed look at the Weibull distribution, which included the characteristics of the estimated parameters, beta and eta. However, the location parameter, gamma, was not discussed in much detail. In many cases, the location parameter may be assumed to be zero, but in this month's issue we will take a closer look at the the location parameter and how/when to use the 3-parameter Weibull distribution.

To read more, see 

Tool Tips  

The Tool Tips section addresses helpful hints and frequently asked questions about ReliaSoft software products.

  • How do I specify which stress levels to be displayed on the probability plot in ALTA 6?

  • How do I remove the stress library from a Folio in ALTA 6 PRO?

To read more, see 

Hot News
*    Reliability Training Seminars - Upcoming ReliaSoft public reliability training seminars include:


Master the Subject, Master the Tools training seminar for life data analysis, accelerated life data analysis and system reliability: May 20 - 24, 2002 in Tucson, Arizona. For more information, see


QALT Boot Camp intensive three day course on advanced topics, concepts and applications of quantitative accelerated life testing (QALT), such as time-varying stress, multiple stress testing and ReliaSoft's ALTA PRO software: June 26-28, 2002 in Tucson, Arizona. For more information, see
*    ReliaSoft at the SAE TOPTEC - ReliaSoft will be participating at SAE International's TOPTEC workshop to be held May 7-8, 2002 at the Westin Southfield Hotel in Southfield, Michigan. This two day TOPical, TEChnical workshop addresses Accelerated Stress Testing and Reliability & Failure Analysis. Be sure to attend the presentation of Quantitative Accelerated Life Testing (QALT) given by ReliaSoft's President and CEO Pantelis Vassiliou on Wednesday, May 8th. For more details, see

ReliaSoft to co-sponsor the 28th Annual Reliability Testing Institute  - Along with Boeing, Caterpillar, Dell, Eaton, Honeywell, Raytheon, General Electric and Siemens, ReliaSoft will once again be co-sponsoring the Annual Reliability Testing Institute. The institute will be held May 13-16, 2002 in Tucson, Arizona. If you will be attending the institute, we would love to meet you at the ReliaSoft corporate headquarters, conveniently located nearby. Call +1.520.886.0410 if you would like to arrange a meeting to discuss your reliability needs. Also, be sure to attend the overview of ReliaSoft's reliability engineering software tools, given by ReliaSoft's President and CEO Pantelis Vassiliou on Tuesday, May 14th.

ReliaSoft at AQC - ReliaSoft will be participating at the ASQ's 56th Annual Quality Congress (AQC) to be held May 20-22, 2002 at the Colorado Convention Center in Denver, Colorado. ReliaSoft will be at booth 353 (across from the golf simulator) in the vendors' area where you can get information on ReliaSoft's products and services. For more details, see

MSG-3 Maintenance Program Creator Released - ReliaSoft's MPC 3, an MSG-3 compliant maintenance program creator, was released in March, 2002. Developed with Honeywell Aircraft Engines & Systems Group, this software package is specifically designed for the aerospace industry. For more information, see

ReliaSoft at MRO  - ReliaSoft would like to thank those of you who stopped by the ReliaSoft booth in the vendors area during the recent Maintenance, Repair and Overhaul (MRO) Conference and Exhibition in Phoenix, Arizona. We hope that we helped to make this a productive and interesting conference for you.
From The Edge  
In addition to the monthly Reliability HotWire, ReliaSoft publishes Reliability Edge, a printed journal that includes articles and information related to the field of reliability engineering. Articles of interest in the current edition:
  • Using Quantitative Accelerated Life Testing Models for Other Applications - Although the phrase “accelerated life testing” often brings to mind images of temperature chambers filled with electronic components, the methodology for analyzing data from accelerated life tests can also be used in many other applications (e.g. analyses to quantify reliability under different operating conditions, degradation analyses and stability/shelf-life studies). This article provides a brief overview of accelerated life testing analysis modeling and demonstrates the use of the analysis methodology in two non-accelerated applications. See
  • Creating Initial Scheduled Maintenance Plans - The MSG-3 guidelines have been developed to provide the aircraft industry with a logical framework for creating initial scheduled maintenance plans that will be acceptable to regulatory authorities, operators and manufacturers. This article provides a general overview of MSG-3 and discusses the systems and powerplant portion of the analysis in more detail. Finally, we introduce ReliaSoft’s MPC 3 software, designed to assist MSG-3 working groups to accurately and efficiently complete such analyses. See
Share Your Experience
Reliability Specification Experiences Wanted
Reliability specifications are a central component of most reliability analyses. Despite their central importance, there is wide variation within industry as to the format and meaning of reliability specifications. In many cases, there are serious deficiencies in the specifications on which manufacturers base important business decisions. In a future issue of our printed newsletter, the Reliability Edge, we will examine the reliability specifications that are commonly used in industry today. We invite you to participate by sharing non-confidential/non-proprietary information about the reliability specifications that you work with in your day-to-day efforts. Do you have experience with particularly effective reliability specifications? Have you struggled to educate decision makers in your organization about the inadequacies of the specifications that they have adopted? Have you received specifications from a client that just do not make sense?
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