# ALT-1 failure **URL:** \ **Category:** Guest Discussion\ **Created:** [April 14, 2007, 7:10am UTC](https://forum.cirruspilots.org/t/alt-1-failure/41251 "2007-04-14T07:10:08Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![RAG](https://avatars.discourse-cdn.com/v4/letter/r/b19c9b/32.png) [@RAG](https://forum.cirruspilots.org/u/RAG)\ **Post date:** [April 14, 2007, 7:10am UTC](https://forum.cirruspilots.org/t/alt-1-failure/41251/1 "2007-04-14T07:10:08Z")
Has anyone had a Comm/GPS1 fail after an ALT-1 failure in an SR-20 with Avidyne/entegra system + dual 430s?? I know this shouldn’t happen as Gomm/GPS is powered by BAT2/ALT2 in event of an ALT-1/BAT-1 failure. But it happened to me last week and I had to make an unscheduled no-flap landing on tower light signals. What am I missing?? ---
**Author:** ![tedco21](https://sea1.discourse-cdn.com/copa/user_avatar/forum.cirruspilots.org/tedco21/32/101169_2.png) [@tedco21](https://forum.cirruspilots.org/u/tedco21)\ **Post date:** [April 14, 2007, 11:55pm UTC](https://forum.cirruspilots.org/t/alt-1-failure/41251/2 "2007-04-14T23:55:18Z")
> In reply to: > > * * * > > What am I missing?? > > * * * A COPA membership! There are tons of posts regarding these type of problems. I don’t know if you own your plane or rent one. If you fly a Cirrus, do yourself a favor and get a membership. It will be the best $50. you ever spent! ---
**Author:** ![robapens](https://sea1.discourse-cdn.com/copa/user_avatar/forum.cirruspilots.org/robapens/32/79_2.png) [@robapens](https://forum.cirruspilots.org/u/robapens)\ **Post date:** [April 15, 2007, 3:38am UTC](https://forum.cirruspilots.org/t/alt-1-failure/41251/3 "2007-04-15T03:38:58Z")
That is a complex failure. Not really something that can be diagnosed remotely over the internet. ---
**Author:** ![Roger\_Whittier](https://sea1.discourse-cdn.com/copa/user_avatar/forum.cirruspilots.org/roger_whittier/32/85023_2.png) [@Roger\_Whittier](https://forum.cirruspilots.org/u/Roger_Whittier)\ **Post date:** [April 15, 2007, 10:18pm UTC](https://forum.cirruspilots.org/t/alt-1-failure/41251/4 "2007-04-15T22:18:06Z")
> In reply to: > > * * * > > Has anyone had a Comm/GPS1 fail after an ALT-1 failure in an SR-20 with Avidyne/entegra system + dual 430s?? > I know this shouldn’t happen as Gomm/GPS is powered by BAT2/ALT2 in event of an ALT-1/BAT-1 failure. But it happened to me last week and I had to make an unscheduled no-flap landing on tower light signals. What am I missing?? > > * * * RAG, Well, you had a worse failure than a comm and system 1. You don’t really give enough info to trouble shoot, but: 1. You must have flown without alt 1 for quite a while without shedding load, flattening the batt 1. Batt 1 would have lowered the flaps had you recognized the issue and preserved power, assuming it is in good condition. You should monitor these systems closer and have a plan to extend your limited electrical resources when this happens. 2. You either lost alt 2 ALSO (which you correctly state runs comm 1) and ran down the batt 2 (btw the batt 2 needs to be replaced every 2 years so they have adaquite reserve) also OR you lost something they have in common. The MCU is the only common link and it has among other things your voltage regulators on it. The electrical system will do weird things when it fails. Given multiple failures, I think its likely your MCU (Master Control Unit) failed. That is the box on the firewall just in front of the pilots rudder pedals. Hope that helps. There really is a lot of very important details like this in the members area, should you feel like accessing it. I don’t generally cruise the guests section, but my experience is in the members section other members do try to help. At least that is my experience. Good Luck. Please do post what they find. ---
**Author:** ![neoluddite](https://avatars.discourse-cdn.com/v4/letter/n/c6cbf5/32.png) [@neoluddite](https://forum.cirruspilots.org/u/neoluddite)\ **Post date:** [April 15, 2007, 4:35am UTC](https://forum.cirruspilots.org/t/alt-1-failure/41251/5 "2007-04-15T04:35:55Z")
> In reply to: > > * * * > > Question: What am I missing?? > > Answer: A COPA membership! There are tons of posts regarding these type of problems. I don’t know if you own your plane or rent one. If you fly a Cirrus, do yourself a favor and get a membership. It will be the best $50. you ever spent! > > * * * A typical answer from COPA! Only a select few individuals around here will actually answer a non-member’s question(s). Don’t waste your time and money to join either. I did. Once you actually pony up the cash to join, you’ll only be told: "Don’t waste our time. Search the past posts first. If you can’t answer your own question by reading them, then MAYBE, just MAYBE, one of us holier-than-thous will deem to answer you in the most snide manner possible. As the other responder to your question mentioned, it sounds like you’ve had a complex failure scenario. Assuming it didn’t correct itself, I would suggest that you have a good avionics shop trace the obvious wiring fault an correct it. HINT: Most Cirrus service centers DO NOT have good avionics shops. They just play the “swap the broken bits around” game until the system fixes itself. Ask around for a recommendation for a good shop to work with. DON’T bother asking these people because they’ll only tell you to join up so you can use the service center recommendation function. (Ever been in a military recruiter’s office while he’s giving the hard sell to a high school kid? That’s how it works here too. You get promised pie in the sky one day and end up scrubbing pots the next.) ---
**Author:** ![robapens](https://sea1.discourse-cdn.com/copa/user_avatar/forum.cirruspilots.org/robapens/32/79_2.png) [@robapens](https://forum.cirruspilots.org/u/robapens)\ **Post date:** [April 15, 2007, 7:28pm UTC](https://forum.cirruspilots.org/t/alt-1-failure/41251/6 "2007-04-15T19:28:55Z")
> In reply to: > > * * * > > A typical answer from COPA! Only a select few individuals around here will actually answer a non-member’s question(s). … > > * * * So, I answered your question. Does that make me one of the “select few”? Please! > In reply to: > > * * * > > As the other responder to your question mentioned, it sounds like you’ve had a complex failure scenario. Assuming it didn’t correct itself, I would suggest that you have a good avionics shop trace the obvious wiring fault an correct it. > > * * * Well _I_ didn’t say that. All I said it sounded like a complex problem that might not be able to be solved over the internet. And having diagnosed many electrical problems in all manner of things from a Cirrus SR22 with some serious electrical problems, to many MANY other airplanes, to many boats, to many cars, to houses, to complex HVAC systems to building automation systems and way more I stand by that statement. It may be a complex failure or a coincidental failure. But I’ll try to answer it here on the forum. If you would please back your airplane up to the computer and rev it up with the ALT 1 turned on… and e-mail me the sound recording I’ll try to diagnose it. > In reply to: > > * * * > > HINT: Most Cirrus service centers DO NOT have good avionics shops. They just play the “swap the broken bits around” game until the system fixes itself. > > * * * I agree with you. > In reply to: > > * * * > > Ask around for a recommendation for a good shop to work with. DON’T bother asking these people because they’ll only tell you to join up so you can use the service center recommendation function. > > * * * Well Mr neoLuddite, I suppose I could recommend a good shop in Lancaster PA or Toronto but that might incur your wrath in that it is too far from your cave? You know, the Cirrus is not that complex of an airplane. It does not need a specialized shop. Why don’t you ask around locally for a good “Santa’s Workshop” kind of shop and have them check out the obvious wiring chafe points. Have you complied with the chafing wiring SB yet? ---
**Author:** ![fasteddi](https://avatars.discourse-cdn.com/v4/letter/f/67e7ee/32.png) [@fasteddi](https://forum.cirruspilots.org/u/fasteddi)\ **Post date:** [April 15, 2007, 8:53pm UTC](https://forum.cirruspilots.org/t/alt-1-failure/41251/7 "2007-04-15T20:53:30Z")
There’s a massive amount of data on problems similar to the poster’s available on the member’s side. If someone wants to take the time to cross-post (and duplicate) relevant info on the subject in order to save RAG $50, they’re more than welcome to. I just don’t, is all. And, BTW, I’m not holy at all [;)] ---
**Author:** ![timg](https://sea1.discourse-cdn.com/copa/user_avatar/forum.cirruspilots.org/timg/32/40_2.png) [@timg](https://forum.cirruspilots.org/u/timg)\ **Post date:** [April 16, 2007, 1:43am UTC](https://forum.cirruspilots.org/t/alt-1-failure/41251/8 "2007-04-16T01:43:12Z")
> In reply to: > > * * * > > DON’T bother asking these people because they’ll only tell you to join up so you can use the service center recommendation function. > (Ever been in a military recruiter’s office while he’s giving the hard sell to a high school kid? That’s how it works here too. You get promised pie in the sky one day and end up scrubbing pots the next.) > > * * * Lud, That’s quite a whopper! Did you wake up on the wrong side of the bed today? Let’s see, THIS forum (guests) has 37 threads with 215 posts. The Member’s archive contain has over 18,000 threads. The active Member’s forums contain over 14,000 threads. There’s no false promise here - COPA membership is the real deal, despite your opinion. A majority of the threads start with someone asking a question, and the usual answer is NOT “go away kid, you bother me”. Shoot, I’ve answered hundreds of them and asked a whole bunch. ---
**Author:** ![Roger\_Whittier](https://sea1.discourse-cdn.com/copa/user_avatar/forum.cirruspilots.org/roger_whittier/32/85023_2.png) [@Roger\_Whittier](https://forum.cirruspilots.org/u/Roger_Whittier)\ **Post date:** [April 16, 2007, 2:18am UTC](https://forum.cirruspilots.org/t/alt-1-failure/41251/9 "2007-04-16T02:18:22Z")
> In reply to: > > * * * > > I would suggest that you have a good avionics shop trace the obvious wiring fault an correct it. HINT: Most Cirrus service centers DO NOT have good avionics shops. > > * * * BTW, this kind of failure does not need an avionics shop. All power management of the alternators and the batteries are the domain of an A&P. At least until proven it is the avionics, and this doesn’t sound like that. ---
**Author:** ![2minute](https://sea1.discourse-cdn.com/copa/user_avatar/forum.cirruspilots.org/2minute/32/274_2.png) [@2minute](https://forum.cirruspilots.org/u/2minute)\ **Post date:** [April 17, 2007, 11:48pm UTC](https://forum.cirruspilots.org/t/alt-1-failure/41251/10 "2007-04-17T23:48:32Z")
Wow, _ **deleted by sysop** _