Blog Archives

TECH SPOT: Sample CRE questions


1. Which answer BEST describes the events and operating conditions an item experiences from mission initiation to completion? The events may include the research and development phase, product manufacturing, warehousing, and so on, to mission completion.

A. Operational readiness; B. Mission profile; C. Design adequacy; D. Mission reliability

2. What is System Effectiveness, if Operational Readiness is 0.89, Design Adequacy is 95%, Availability is 99%, Maintainability is 0.93, and Mission Reliability is 0.99? Ebeling, p 149

A. 0.763; B. 0.881; C. 0.837; D. 0.820

3. Which of the following functions are normally accepted reliability engineering tools?

I. Failure probability density function; II. Failure rate function; III. Reliability function; IV. Conditional reliability function; V. Mean life function.

A. I and II only; B. I, II and III only; C. I, II, III and IV only; D. I, II, III, IV and V

4. An airline maintains a fleet of 4-engine aircraft. Its maintenance records show that on the average an engine fails 3 times in 10,000 operating hours with normal preventive maintenance. What is the Poisson distributed probability that 2 or more engines on an aircraft will fail during a typical flying period of 8 hours?

A. 0.000034; B. 0.0000034; C. 0.0000029; D. 0.000029

5. For the exponential model, the reliability at mean time to failure is about:

A. 37 percent; B. 50 percent; C. 67 percent; D. 73 percent

6. A plastics plant operates 8 extruders producing plastic film. Production volume requirements cannot be met if less than 6 extruders are operating. There is a .30 probability that a machine stopping malfunction will occur. What is the probability that 6 extruders can remain operating throughout the day?

A. 0.5783; B. 0.4482; C. 0.5518; D. 0.8059

7. A system is made up of four independent components in series each having a failure rate of .005 failures per hour. If time to failure is exponential, then the reliability of the system at 10 hours is:

A. 0.8187; B. 0.8860; C. 0.9512; D. 0.9802

8. What is the reliability of this system?

Screenshot 2018-03-17 at 16.59.34

Where component reliabilities are: A. 0.80; B. 0.95; C. 0.82; D. 0.85; E. 0.75

A. 0.10; B. 0.90; C. 0.95; D. 0.04

9. Which method is used to predict new device reliability during its early design stage?

A. Burn-in method; B. Part stress analysis method; C. Parts count method; D. Accelerated testing method

10. Which of the following forms of reliability data will BEST provide valuable information on product usage and reliability?

A. In-house test results. B. Independent lab results. C. Field support data. D. Quality control data.

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Free resource on Software Reliability


We get a lot of questions on Software Reliability.

Since we listen to our members we are in the works of setting up more info on this topic.

For the time being we can redirect you to a great free resource you can access on

This is the Handbook of Software Reliability Engineering – Edited by Michael R. Lyu Published by IEEE Computer Society Press and McGraw-Hill Book Company

Software Reliability Handbook

Picture © B. Poncelet

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A Long List of Reasons to Perform an ALT and The Selection of Applied Stresses



A Long List of Reasons to Perform an ALT:

A. Confirm a minimum life estimate or time to first failure of a large population.

B. Look at variability or robustness of the manufacturing process.

C. Determine whether screening will be required for production to meet customer requirements or market goals.

D. Look at the impact of various customer environments, such as duty cycle, on the performance or ultimate life of a system.

E. Determine if customer rough handling, customer abuse or customer misuse is a significant factor in the expected life of a product in the field.

F. Identify the impact of software redundancy to hardware and hardware redundancy to the proper and continuous system operation.

G. Determine if little-used, emergency or “one-shot products” will operate properly when called upon to do so. This is especially true of warning systems or emergency systems such as fire alarms or extinguishers.

H. Show that no dangerous situations exist for a product. This covers all aspects of liability, hardware and software warnings and system safe operating conditions and fail-safe modes.

I. Estimate the acceleration factor for a component or system with respect to a specific set of customer stresses.

J. Demonstrate successful customer operation and maintenance across the many divergent customer environments and customer use conditions.


The Selection of Applied Stresses:

A) Select standard environmental stresses, including items such as high temperature, low temperature, random vibration, dust or humidity.

B) Select cyclic stress conditions, such as temperature cycling, humidity cycling, stress cycling or sine wave vibration.

C) Select stresses that are frequently called out in the Military Standards and have been found useful to demonstrate conformance to stringent military customer environments.

D) Select stresses based upon tradition for the market or business. These may be unique to an industry or situation.

E) Select stresses based upon the expected customer environment or industry. This includes consideration of worst-case customers, abusive customers and customer who fail to perform suggested maintenance.

F) Select stresses based upon known or anticipated failure modes or physics of failure for critical components or system functions. Such stresses are thought to dominate the operation of a system

G) Select stresses based upon customer safety or liability considerations.

H) Select stresses based upon long term degradation modes such as corrosion or material degradation.


Published in Practical Weibull Analysis Techniques – Fifth Edition by James A. McLinn Published by  The Reliability Division of ASQ – January 2010 ISBN 0277-9633 (available as free download for ASQ Reliability Division Members)

Picture © B. Poncelet


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2017 ASQ Reliability & Risk Division – Volunteer of the Year

On behalf of the ASQ Reliability & Risk Division Management Committee, we congratulate Jim Breneman for the 2017 Volunteer of the Year Award

Screenshot 2018-02-06 at 08.24.21

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2017 ASQ Reliability & Risk Division – RAMS Best Paper

On behalf of the ASQ Reliability & Risk Division Management Committee, we congratulate Dr. Wayne Nelson for the 2017 RAMS Best Paper, Cost Optimal Sudden-Death Life Testing.

Screenshot 2018-02-06 at 08.23.54

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Last day of RAMS 2018

Already last day of RAMS 2018.
Still time to view some sessions and attend the paper session.
Below some pictures from the last day to have an impression how it was.









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RAMS 2018: General Reception & Banquet

No RAMS without a general reception and banquet.
In the end a picture of some of the ASQ Reliability and Risk Division Leaders present.










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3rd day of RAMS 2018

Again some interesting cases and tutorials on the third day of RAMS 2018.
Below some impressions

– Physics of Failure Laws Using Thermodynamic Degradation Science by Alec Feinberg
– The Panel – Advisory Board
– Software Development Process and Reliability Analyses by Milena Krasich
– Risk Management Principles and Techniques by Rick Jones

And some of the food.








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RAMS 2018 ASQ Reliability and Risk division / ASQ Electronics & Communications Division annual diner

This year the RAMS 2018 ASQ Reliability and Risk division / ASQ Electronics & Communications Division annual diner took place in the Wild River Grille – River Room.

Apart from a diner, the Volunteer of the year and paper award where announced.








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2nd Day of RAMS 2018

Some impressions of the second day of RAMS.
Since it is impossible to cover it all we have only a few presentations covered

-Function-Based Resiliency: Improving Performance through Adaptive Management by JD Solomon, CH2M
-Balancing Reliability with Program Goals During Product Development by Adam Bahret, Apex Ridge Reliability
-Surface Mount Reflow Profile Impacts On Reliability by Greg Cennamo, L3 Technologies
-Objectives Based Assurance Management by Martin Feather, NASA JPL Office of Mission Success
-Design and Analysis of Accelerated Life Tests by Rong Pan
-Alternate approach to prediction of IC failures using silicon based degradation mechanisms by Ashok Alagappan, DFR Solutions
-Accelerated life testing of heat exchangers by Julio Pulido, ReliaRisk
-Assessing the Vibration Fatigue Life of Engine Mounted Components by Marco Bonato, VALEO
-Prediction of Acceleration Factor for Accelerated Testing of Photovoltaic Modules Installed Around the World by Arun Bala Subramaniyan
-Understanding and Applying the Fundamentals of FMEAs by Carl Carlson


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Webinar Categories
Recent Webinars
  • Reliability Analysis using Reliability Block Diagram( RBD)
    April 12, 2018
  • Human-in-the-Loop: Predictive Modeling of the Likelihood of a Vehicular Mission or an Extraordinary Situation Outcome
    May 10, 2018
  • Capital Asset Management – Prioritizing Critical Assets and Securing Their Reliability Description
    June 14, 2018

Provide a global forum for networking among practitioners of reliability engineering, management and related topics.


Facilitate growth and development of division members,


Provide Resources

Promote reliability engineering principles and serve as a technical resource on reliability engineering for ASQ, standards agencies, industry, government, academia and related disciplines


Sponsor, present and promote reliability, maintainability, and related training materials for courses, symposia, and conferences.