No good deed goes unpunished

Please let me know where the standby pump is, I could not find one.

Gee I didn't think you would look. Maybe the tech rep can help. I would hate to lose the essential buss again while in flight. Go ahead and be flippant. Two 50 amp fuses are not a joke.

Frankly, I applaud Bill. He's the type of mechanic I like. He also posts here at BT for us to take aim at him. Chasing airplane gremlins is an unappreciated job.

His previous post about the flap motors added one more piece of info to my arsenal.

Here's to you Bill

The Duke has 3 of those Fuses, one next to the Battery and on in each cowling where the output from the Alternator/Generator crosses the firewall.

And a Spare Fuse mounted right next to each of them! replacements can be had for 200buck from Aircraft Spruce or 15 bucks from truck and marine supply online store.

Nonetheless, i spent a cold late december afternoon on the KTEB ramp with brand new tools from Ace hardware nextdoor to replace one of those with no power tools to remove the 60 or so screws that hold the battery box cover in place. Not a single mechanic in 100miles wanted to assist.

Right back at you Michael. Thanks!!

I may have to contact the tech rep to find that pump as a last resort.

Let us dispense with the clowning banter. Now that you have established there is no stand-by vacuum pump in this SR22, you have obfuscated more than enough. Please answer a few questions and elaborate why.

1) You found two blown 50 amp fuses. Did they then severely limit the "essential" bus capability by removing the main sources of power?
Yes or no?

2) Did you do anything beyond speculate per your initial comment as to the cause of the fuses doing their job? To wit:
"When flaps were selected to 0 the motor didn't quite get to zero so the motor continued to run.
I am thinking this had something to do with the fuses but time will tell.
It could have also had a GPU connected while the battery was removed during it's recent annual..."
Again. Yes or no and why

3) There is a detailed procedure you performed to test the MCU with a work chart for recording results. Will you post a copy of the chart with us?
Yes or if no, then why.

Let us dispense with the clowning banter. Now that you have established there is no stand-by vacuum pump in this SR22, you have obfuscated more than enough. Please answer a few questions and elaborate why.

1) You found two blown 50 amp fuses. Did they then severely limit the "essential" bus capability by removing the main sources of power?
Yes or no?

2) Did you do anything beyond speculate per your initial comment as to the cause of the fuses doing their job? To wit:
"When flaps were selected to 0 the motor didn't quite get to zero so the motor continued to run.
I am thinking this had something to do with the fuses but time will tell.
It could have also had a GPU connected while the battery was removed during it's recent annual..."
Again. Yes or no and why

3) There is a detailed procedure you performed to test the MCU with a work chart for recording results. Will you post a copy of the chart with us?
Yes or if no, then why.

No he doesn't have to answer to me. The question, also asked by others involves the "undetermined cause of two blown 50 amp fuses'. I find the cavalier response to be objectionable. Stand up on a pedestal and claim how finally doing what should have been done in the first place(troubleshoot before going to the tech rep) makes you special is also objectionable. Is it a problem to ask simple questions that could further his status?
Incidentally, the status check of the MCU is imperative since it was compromised enough to blow those two fuses to the Essential buss. Many Cirrus service centers would have replaced it just to be safe, RE: the tech suggestion. An issue with an aux power hookup should have only blown one fuse. So maybe putting his butt on the line to save the customer $2K could be heroic. Is there a problem with defining a reasoned examination and testing protocol before making the decision? Without some definitive answers I remain skeptical. If you have ever been in the dark on a moonless night with a blank panel and only a few dim lights on the ground to help keep you upright, you might understand.

Bill stated previously that he ops checked the MCU. I would give him the benefit of doubt that it was in accordance with the AMM. Unfortunately, replacing the MCU also carries risk until proven otherwise. It may work up to the point of failure but hopefully within the warranty period. In such a case, I would advise against any night/IFR flights until some flight time was put on any repairs that were accomplished. I hate it when a part is changed for troubleshooting and no fault found, which happens a lot with all the new techno gadgets. Gets expensive and wasteful.

Thanks Bill for posting. I know a Cirrus owner and from what I hear from him, often times MCU is wrongly blamed. Good you went the extra mile, thank you!

Bob,

I am glad to see that someone who has admitted in writing here that he does not know what he is doing re Cirrus electricals:

"My Service CD is missing in action so I am unable to determine what they protect and the "procedure" alluded to."


is still willing to ask questions and try to learn. Me, I never found rudeness to be a useful learning technique....

RAS

I have thought about this thread for a few days now.
I am not sure what I have done to Mr. Butts, but (however) I get the feeling he doesn't like me. Don't know why as we've never met, probably never will.

To answer his question, Yes I did perform the MCU checkout by the book (I have current copies, that are updated regularly). The checkout was failing with the low volt light on when it shouldn't be and no I won't post the results on here as you probably would not be able to read my chicken scratches.

I was also paying attention to buss voltages as well as amp readings while running the aircraft. The indications I was getting were not covered by the maintenance manual. This is where experience comes in. Mr. Butt may feel I was being flippant and I probably was but this ain't my first rodeo. Sure I could have done as the tech suggested and just change the MCU but the only one available was a repaired one. I figured I might as well try to repair this one. After I changed the midi fuses I performed the MCU checkout procedure again and it passed.

As I stated before I don't know why the fuses blew, but since it had just come out of an annual and it was also flying around with a flap motor that was constantly running the "root" cause could have been one of these two events and most likely the result of connecting a GPU to the system with the battery removed.

I can't tell you why they blew. I didn't perform the annual and I wasn't there when it was performed, so I don't know what was done to it.

I can tell you that the shop that performed the annual, installed an SB on the flap motor incorrectly causing that problem.

Last year they over torqued the air/oil separator upper nut causing venturi effect that was sucking oil out of the engine.

The owner keeps taking it back to the same place for the annuals and then let's me repair things during the year and I 'm ok with this.

The aircraft has been flying with no further issues so maybe I got it right this time.