Forum: Reliability & Maintainability Questions and Answers
Posted by: Scott Tamashiro (email@example.com )
Date posted: Thu Mar 29 17:26:46 US/Eastern 2001
Subject: TWT Power Levels
An inquiry came up regarding the TWT failure rate model. Although the 217F2 handbook provides a range for rated power (1 mW to 40 kW) as a parameter, I am interested as to what the actual field power levels were that formed the 217F TWT failure rate equation. I was wondering what power levels (up to 500W? up to 1kW?) are represented in the dataset EIA Microwave Tube Divsion provided. Thank you, Scott
Posted by: Cathy
Date posted: Thu Mar 29 17:21:13 US/Eastern 2001
Subject: Passive Component "Uprating"
Is there any standard or guideline for passive component uprating? Actually I need the justification for PiT used in MIL-HDBK-217 prediction. For example, what's the PiT of a resistor (rated at 150C) at 240C? Thanks.
Posted by: Luke Deng (firstname.lastname@example.org )
Organization:Aerospace Industry Development Corp.
Date posted: Thu Mar 29 3:26:28 US/Eastern 2001
Subject: Maintenability Index
What's MAINTENABILITY INDEX meanning in physic and mathematic aspect?
Posted by: Jim Miller (email@example.com )
Organization:United Defense, L.P.
Date posted: Wed Mar 28 14:16:21 US/Eastern 2001
Subject: Reliability Prediction Confidence Level
We are being asked to provide a confidence level (percent) to our current reliability prediction of a Navy mechanical/electrical/electronics system still in preliminary design. Several areas of the design are still in the "maybe it will be like this" stage. Prediction data sources currently include a mix of handbook, data supplied from hopeful vendors, 217, and Navy / Army failure rate data of similar items we may be using in the new design. Can a confidence level be assigned or calculated at this stage of the prediction, or at any stage of the prediction? If so, is there an established methodology for doing so? We understand that as the design goes forward and actual hardware is specified and tested, and subassemblies are built and tested, we can incorporate vendor data, testing data, FRACAS data, etc. into the prediction, thereby increasing our "confidence" in the prediction. But can this confidence ever be quantified?
Posted by: J dudley (Jonathon.firstname.lastname@example.org )
Date posted: Tue Mar 20 10:36:37 US/Eastern 2001
Subject: Testability sample sizes
Sample sizes for testability demostrations MIL hdbk471 seems to be very a little miss leading as towards the sample size required to test for T demos.Could some body explain thier own theory on the methods published in this standard. We belive that 10 percent of the fault catalog should be demostrated.