Comments on: When Your World Rolls Over

By: Blake Morrison

Blake Morrison — Thu, 13 Nov 2008 02:05:16 +0000

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By: Dick Lawrence

Dick Lawrence — Fri, 06 Jun 2008 12:59:47 +0000

I’ll try- this is a partial answer because I’m not anywhere near my plane to see the table I created with the standby system. I did install a Precise Flight system on my ’68 Arrow and then disconnected the vac pump to calibrate it. My mechanic suggested that while 5″ vacuum is ideal for vacuum instruments, they normally do well at 3″. So I did the cal and found that I could fly at 10-12k’ with about 4″ vacuum. Above that I would have to close the throttle a little to get 4″. I’m going on memory now- from the test I did 5 years ago, but I believe I had adequate vacuum (3″) at 12,000′ to run the two vacuum instruments. The vacuum is pulled from one side of the engine and affects those cylinders or that cylinder- not sure if one or two- more than the others. Bottom line is that it should work well at 7-8 k and probably at 12k as well. But, if you install one, do your own calibration for your aircraft. And, experiment with what vacuum is actually needed to give you reliable readings. If 3″, then set your own personal minimum- my instruments do o.k. at 3″ so I would adjust the throttle to give around 4″ if in IMC. I also have a G396 and its panel display would help make it a safe flight.

By: Cary Alburn

Cary Alburn — Fri, 23 May 2008 16:35:10 +0000

I’m curious how in the “real world” the Precise Flite vacuum backup that draws from the intake works at any higher altitude. I’ve heard stories that at the altitudes we fly in this part of the country (typically 10-11 thou on a cross country, 7-8 thou more locally) they don’t provide enough vacuum to keep the gyros turning. Yet if they do work, that would be a cost effective consideration for my legally IFR little bird, whereas many of the other backups are really too pricey to consider. Any comment from real world users?

By: Chic Wilson

Chic Wilson — Fri, 23 May 2008 14:31:03 +0000

I agree with those pilots commenting that a portable GPS with panel page is a practical, affordable, reliable backup. My Garmin 296 is quick and accurate enough to keep the aircraft upright and on course. Even an NDB approach is a no-brainer if that is your best airport option.

By: Don Vreuls

Don Vreuls — Sat, 17 May 2008 01:09:49 +0000

Have Mid-Continent Electric Attitude Indicators with 1 hour battery backup (and slip indicators) replacing the turn coordinators in both my single and twin. The twin has two vacuum pumps, and two alternators. Both aircraft have low vacuum warning lights (to help mitigate confusion should the attitude indicator slowly decay). Also, I check vacuum pumps for wear at each 100 hour inspection and replace them between 400 and 500 hours. I have Garmin certified GPSs in the panels, and a portable 496 for use in each aircraft offering battery operated GPS derived track, turn rate, altitude rate and altitude.

By: Kurt White

Kurt White — Wed, 14 May 2008 19:46:45 +0000

My first vacuum pump failure came while I was earning my instrument ticket. My instructor had covered my attitude and directional gyro so that I could practice partial panel approaches. When we removed the covers to make one more approach with full panel, it was discovered that the vacuum pump had failed. That was a great lesson for me to keep current on partial panel.

By: Dave Wilson

Dave Wilson — Wed, 14 May 2008 00:05:12 +0000

I have a back up vacuum system and a back up electrical system. Both systems have failed in IMC prior to investing in the back up systems. I attempt to “train” at least every three months utilizing an instructor performing partial panel. The vacuum failure after installing the back up system in IMC was a “non” event; confidence and the plan working is a wonderful experience.

By: Karl L. Roesch

Karl L. Roesch — Sun, 11 May 2008 13:34:27 +0000

Hi
Most of the vacuum pump failures, I hear, are with dry systems.

Why are there not more wet vacuum pump installations ? The oil recovery unt would add little weight to the installation

Karl

By: James W. Johnson

James W. Johnson — Sun, 11 May 2008 12:07:20 +0000

I have experienced vacuum and electrical failures on seperate occasions during 25 plus years of flying single engine airplanes. I have a standby vacuum system (precise flight) as well as an s-tec autopilot to help out during a vacuum pump failure. I also keep a garmin 496 plus a hand held navcom on board in case of an electrical failure. I would not feel comfortable flying IFR without having backup systems in place.

By: joe grimes

joe grimes — Sat, 10 May 2008 02:35:46 +0000

I have backup AI, twin wet vacuum pumps and twin generators (Cessna 310) and obsess over maintenance. I suppose I will take what I get and not lose any sleep over it.