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SVS Backup Vacuum System

n1469t

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I have a complete SVS Backup Vacuum system that was just removed from my Arrow when I converted to all electric.

It worked when removed and includes the hoses, vacuum switch, warning light. Everything to make it work. I have the operating manual but not the installation manual.

I am offering it for free. Just pay $15 for shipping. (Not trying to make any money, just hoping to help keep others in the air).
 

Canuck

David Megginson (he/him)
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That's very generous. I won't take you up on the offer, even though I'm still vacuum-based, because I think my plane has enough backup these days (in addition to the electric TC, I have an A/P that doesn't rely on the vacuum system and two AHRS sources, one of them panel-mounted). But I hope it finds a good home.
 

arkvet

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I have considered a backup vacuum for my Saratoga... My Century 41 autopilot runs off the vacuum driven AI so in the event of a vacuum failure my AP dies. However, I have dual G5's and an IFD 550 with synthetic vision, therefor the vacuum AI isn't essential for anything other than my autopilot which is not an essential item to get me safely to the ground.

That is a VERY generous offer and I know there is someone out there that could really use this more than I.

I too hope it finds a good home.
 

Tweety

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Is yours an SVS III? There is some difference in the continuing airworthiness requirements that makes the SVS III easier to maintain. The difference appears to be the serial number of the diverter valve. The S/N should be on a label on the valve, and also may have been recorded in the operations manual.
 

cappy48

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I have considered a backup vacuum for my Saratoga... My Century 41 autopilot runs off the vacuum driven AI so in the event of a vacuum failure my AP dies. However, I have dual G5's and an IFD 550 with synthetic vision, therefor the vacuum AI isn't essential for anything other than my autopilot which is not an essential item to get me safely to the ground.

That is a VERY generous offer and I know there is someone out there that could really use this more than I.

I too hope it finds a good home.


Have one of these systems. and have used it... like it...

Cap
 

BGFYankee

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I'm always late to the party! This would've been a much welcomed addition to the Lance. Already had one vacuum failure...glad it was clear and a million that day. Been eyeballing one of these.
 

Tweety

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I Have the SVS II system installed on my Cherokee, and appreciate it even though I'm not instrument rated. But I've found a few things. It is really most effective at lower throttle settings. There is a chart that shows the vacuum produced at different altitudes and engine RPMS. It is a good idea to cycle the system after each start-up while the engine is idling, because at higher power settings it's hard to tell if the SVS is working or your vacuum pump is working. Also, I am concerned about the effect of adding additional, un-metered air downstream of the carburetor because the last thing I'd want in a vacuum failure is a rough running engine, but at altitude I can always richen up the mixture to compensate. I'm sure if I had an engine analyzer I'd see the effect on the cylinder that the vacuum fitting is on.

The SVS II diverter valve has an AMOC for continued airworthiness that requires the diverter valve to be removed and the opening checked with a wire feeler gauge. The regular airworthiness test is to disconnect the vacuum pump (!!!) and operate the system with a test flight, so be prepared to bring your AP along for a test flight if you don't use the AMOC. I don't think the AMOC applies to earlier versions of the SVS diverter, so check the documentation and the diverter S/N if you want to use the AMOC. Info is on the website for the company that holds the SVS rights now.
 

cappy48

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It is really most effective at lower throttle settings. [B said:
Correct...[/B]

It is a good idea to cycle the system after each start-up while the engine is idling, because at higher power settings it's hard to tell if the SVS is working or your vacuum pump is working.

It is in our preflight check list...

Also, I am concerned about the effect of adding additional, un-metered air downstream of the carburetor because the last thing I'd want in a vacuum failure is a rough running engine, but at altitude I can always richen up the mixture to compensate.

No roughness noted during use...

I'm sure if I had an engine analyzer I'd see the effect on the cylinder that the vacuum fitting is on.

But I will try ours and note the EDM indications ...

From one who used it in IMC.. He said he was at 8000 ft. when , in his words, "the pump went for a dump"..

The red light was the warning, so he pulled the SYS on, the light went out but flickered occasionally (it is set at about 3 - 3.5 inches) Declared an emergency and received a clearance for lower, retarded some power and the light went out completely ... The SVS did its job for the rest of the decent and flight.. instruments operated normally.

We lost our pump in flight years ago but were VFR..

I do like the idea of a back up...

Cap
 

Tweety

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Here's the website for the current maker of the SVS system:

http://www.thevacsource.com/

It's nice that they provide all the installation and maintenance info on their site, unlike some other PMA folks. Note that they also sell parts, so that if you need a new placard you can get it from them.

Here's a link to info about the AD and AMOC for the earlier versions:

https://www.aopa.org/advocacy/advoc...d-for-precise-flight-standby-vacuum-system-ad

My SVS III was in the higher S/N range so I comply by holding the updated service manual which includes the alternate test method for the shuttle valve.
 
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