CRE Technical Standards and Specifications 3 — Questions and Answers
Question 1: Which reliability standard specifically addresses the application of FMECA methodology for military systems and equipment?
- MIL-STD-470
- MIL-STD-1629A (Correct answer)
- MIL-STD-2155
- MIL-STD-756
Correct answer: MIL-STD-1629A
MIL-STD-1629A defines procedures for performing Failure Mode, Effects, and Criticality Analysis (FMECA) on military systems.
Question 2: According to IEEE 493 (Gold Book), what is the primary objective of reliability analysis in industrial power systems?
- Minimizing capital expenditure on redundant equipment
- Quantifying the reliability and availability of power supply to loads (Correct answer)
- Selecting the lowest-cost switching devices
- Complying with OSHA electrical safety requirements
Correct answer: Quantifying the reliability and availability of power supply to loads
IEEE 493 (Gold Book) provides reliability analysis methods to quantify the expected frequency and duration of power interruptions to industrial and commercial power systems.
Question 3: What does the 'Design Eye' concept in DO-160 environmental testing specify?
- Visual inspection criteria for circuit board assembly
- Waveform envelope for conducted susceptibility tests
- The range of human visual acuity for instrument readability
- Environmental conditions that airborne equipment must withstand (Correct answer)
Correct answer: Environmental conditions that airborne equipment must withstand
DO-160 (RTCA/DO-160) establishes standardized environmental test conditions and procedures for airborne equipment to ensure it withstands its operational environment.
Question 4: In the HALT (Highly Accelerated Life Testing) methodology, what is the primary goal of applying stepped stresses beyond rated limits?
- Qualify products to MIL-SPEC environmental requirements
- Identify the fundamental limits of a product's design quickly (Correct answer)
- Determine the Weibull shape parameter accurately
- Generate warranty cost estimates for pricing models
Correct answer: Identify the fundamental limits of a product's design quickly
HALT applies accelerated stresses beyond operational limits to rapidly expose design weaknesses and margins, enabling design improvements before production.
Question 5: Under the IEC 60300 series (Dependability management), what does the term 'availability' formally represent?
- The probability that an item is in a failed state at any given moment
- The ability of an item to be in a state to perform a required function under given conditions at a given instant (Correct answer)
- The total time an item is in preventive maintenance
- The ratio of operating time to scheduled production time
Correct answer: The ability of an item to be in a state to perform a required function under given conditions at a given instant
Per IEC 60300, availability is the ability of an item to perform its required function under stated conditions at a given instant or over a stated period of time.
Question 6: Which ASME standard governs the design and inspection of pressure vessels in the United States?
- ASME B31.3
- ASME Section VIII (Correct answer)
- ASME Y14.5
- ASME B16.5
Correct answer: ASME Section VIII
ASME Boiler and Pressure Vessel Code (BPVC) Section VIII provides mandatory rules for design, fabrication, inspection, and certification of pressure vessels.
Question 7: What is the key difference between a 'specification' and a 'standard' in the context of reliability engineering documentation?
- Specifications are legally binding; standards are voluntary guidance documents
- Specifications define requirements for a specific product/system; standards define general requirements applicable across many products (Correct answer)
- Standards are developed by government agencies; specifications by private companies
- Specifications apply only to hardware; standards apply only to software
Correct answer: Specifications define requirements for a specific product/system; standards define general requirements applicable across many products
A specification states particular requirements for a specific item or system, while a standard establishes uniform technical criteria applicable broadly across products or processes.
CRE Technical Standards and Specifications 3
Which reliability standard specifically addresses the application of FMECA methodology for military systems and equipment?