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#11
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I have a simplistic question. Did the battery replacement "cure" the
problem? "Robert Bonomi" bonomi@c-ns. wrote in message ... In article , Gerry Caron wrote: "A@AA" wrote in message ... Jim, assuming that the ELT does act as he believes it does - that it alarms when a secondary battery dies, and that happens shy of it's stated service life - I'd think that was bad. That's one helluvan assumption. Is 3 years in use shy of it's stated service life? What is the stated service life? I hate (not! to inject facts into a good argument, but the original poster _did_ indicate the stated service life. FIVE YEARS. It died at just short of _four_. *HIS* revised new* 'replacement schedule', based on the observed evidence, is now three years. Did it alarm because the battery died or was there a short in the remote that drained the battery and triggered the ELT? If there was a short, was it internal to the battery (random failure), caused by a cold solder joint (workmanship), water/moisture intrusion or excessive vibration from a poorly located mount (bad installation), or a large current induced into the connecting cable (secondary effect)? There are lots of possible failure modes and results. Until you've analyzed the failure and determined the root cause, you can draw no conclusions regarding the design or anything else. As for being bad, maybe not. What does the System Safety Analysis say? Which is worse; a latent failure where it doesn't work when you need it or a false alarm? At least with the false alarm you are alerted to the fact it's not working. You do monitor guard, don't you? If you can't call it a design flaw, what do you call it? A Bad Thing(tm)? Maybe, or possibly a Feature? ;-) It could be that way because it's the safest failure mode. Or maybe the company (and their lawyers) wanted it that way. Much more likely to be sued if it fails to work after a crash than if it false alarms. Then again, it could be a very unlikely random failure mode. That last can be dismissed. The original poster stated "*IF* a dying battery *ALWAYS* causes a false alarm..." as the qualifying condition for claiming design flaw. That precludes the possibility of an 'unlikely random failure mode'. And don't try to argue that random failures are design flaws. Take a course in reliability engineering. If you're bored, read MIL-HDBK-17. I agree, he should contact the manufacturer before coming to an open forum and posting stuff like this, it may be a completely different situation than what he's describing. He absolutely should. The holder of a TSOA is legally bound to investigate reported failures of their product. (note the key word "reported.") If they find a design flaw that compromises flight safety, they must report it to the FAA within 24 hours. They'll probably argue with the FAA over the corrective action, but they will report it. If they don't report it, they risk having their TSOA pulled and their business shut down. Even minor issues can result in SILs or SDRs, which exist to improve the product and safety so it pays to report it. But it might be *exactly* as he's describing, and I don't think his lack of an EE degree means he can't reasonably comment that a product's designed in failure mode is awfuly unwise. True, it might be exactly as described, but I'm with Jim on this one. I don't think that even with an EE degree he can reasonably comment on the design. Only someone who has specific knowledge of the design and can evaluate all the data surrounding the failure can make a reasonable comment. In 26 years in aerospace, I've learned a few things. One of the big ones is to not publicly speculate on a failure--you're probably wrong and will only make a fool of yourself. Get the data, analyze it, verify cause and effect, and only then make your statement. Gerry |
#12
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"Del Rawlins" wrote in message ... On 10 Jul 2003 04:32 PM, Gerry Caron posted the following: Aviation is a small community. Avionics is only a small part of that. Everybody knows everybody or someone who does. This isn't an industry where companies can afford to alienate customers. JPI still seems to be in business. And NARCO... |
#13
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I have a simplistic question. Did the battery replacement "cure" the
problem? Yes. I also tried installing the old "not quite dead yet" battery in again. 3 times installed, 3 times set the ELT off. I planned to take a variable power supply and work the voltage down slowly from 6 volts to zero, but can't find my power supply. Also, faxed ACK on Thursday. As of today, nothing heard... but maybe they were busy with Arlington. HTH, Mike Palmer Excellence in Ergonomics |
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