Vacuum Failure Enroute to Florida

[Alan Fox]

A couple of things to consider , 1) as far as the Vacuum pump showing a pre failure warning on the gage , its not going to happen , The vacuum pressure is regulated by the regulator , and not the pump , the pump is capable of putting out 3 or 4 times what it is regulated down to and if it gets below that failure is imminent.......  2) the myth or backflow of carbon dust , If the reserve of vacuum in the piping to the instruments causes a backflow , its not getting past the regulator argue all you want , not happening , if this was the case they would have a system in place to prevent it.....  3) this is for Peter Garmin , We waited 8 (count em)  years for King to get certification on the KSN770 ,  their track record sucks , I wouldn't hold my breath for the KI300 , For the life of me I don't understand why they announce these things prematurely.....  Yes it looks great , so did the KSN770 .......

[cnoe]

1 hour ago, n74795 said:

2) the myth or backflow of carbon dust , If the reserve of vacuum in the piping to the instruments causes a backflow , its not getting past the regulator argue all you want , not happening , if this was the case they would have a system in place to prevent it.....

 

I'd sure like to hear a couple more opinions on this as I've been told otherwise by individuals much more knowledgeable than myself.

My understanding was that the suction regulator is not a check valve and simply allows air to bleed "in" through the garter filter to maintain a constant pressure (negative) in the system. I've held my own in my hands for service but don't remember blowing through it in each direction to see if flow was restricted in one direction.

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[Guest]

9 hours ago, N1395W said:

Best alternate vacuum for me is an STEC autopilot.  It uses the turn coordinator to keep the wings level, and in wing leveler mode you can fly the course your GPS tells you.

If you have GPSS it will still fly a rock-solid GPS approach to minimums- all while your AI and DG are dead.

Not just the S-Tec, the Britain is the same.

Clarence

[Marauder]

1 hour ago, n74795 said: 2) the myth or backflow of carbon dust , If the reserve of vacuum in the piping to the instruments causes a backflow , its not getting past the regulator argue all you want , not happening , if this was the case they would have a system in place to prevent it.....  

I'd sure like to hear a couple more opinions on this as I've been told otherwise by individuals much more knowledgeable than myself.

My understanding was that the suction regulator is not a check valve and simply allows air to bleed "in" through the garter filter to maintain a constant pressure (negative) in the system. I've held my own in my hands for service but don't remember blowing through it in each direction to see if flow was restricted in one direction.

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I always thought the vacuum was pulling towards the pump, not away from towards the instrument?

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[rbridges]

13 minutes ago, Marauder said:

I always thought the vacuum was pulling towards the pump, not away from towards the instrument?

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I always thought that too, but I didn't know if there was some kind of sudden/short reversal when the vacuum died?

[cnoe]

1 hour ago, n74795 said: 2) the myth or backflow of carbon dust , If the reserve of vacuum in the piping to the instruments causes a backflow , its not getting past the regulator argue all you want , not happening , if this was the case they would have a system in place to prevent it.....  

I'd sure like to hear a couple more opinions on this as I've been told otherwise by individuals much more knowledgeable than myself. My understanding was that the suction regulator is not a check valve and simply allows air to bleed "in" through the garter filter to maintain a constant pressure (negative) in the system. I've held my own in my hands for service but don't remember blowing through it in each direction to see if flow was restricted in one direction.

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I always thought the vacuum was pulling towards the pump, not away from towards the instrument?

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Absolutely, that is the common setup, though some planes employ a positive pressure system to spin the instruments and pressurize deice boots.

But as I understood it when a vac pump goes out it's usually catastrophic with the carbon vanes vaporizing to some degree. At that point vacuum at the pump goes to zero almost instantly but that the hoses, fittings, regulator, instruments and cabin filter briefly contain some residual negative pressure. Reportedly this may allow a small amount of carbon dust to be sucked back into an instrument.

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[Guest]

2 minutes ago, cnoe said:

Absolutely, that is the common setup, though some planes employ a positive pressure system to spin the instruments and pressurize deice boots.

But as I understood it when a vac pump goes out it's usually catastrophic with the carbon vanes vaporizing to some degree. At that point vacuum at the pump goes to zero almost instantly but that the hoses, fittings, regulator, instruments and cabin filter briefly contain some residual negative pressure. Reportedly this may allow a small amount of carbon dust to be sucked back into an instrument.

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The question with no answer, suck or blow?

Clarence

[cnoe]

2 minutes ago, cnoe said: Absolutely, that is the common setup, though some planes employ a positive pressure system to spin the instruments and pressurize deice boots.

But as I understood it when a vac pump goes out it's usually catastrophic with the carbon vanes vaporizing to some degree. At that point vacuum at the pump goes to zero almost instantly but that the hoses, fittings, regulator, instruments and cabin filter briefly contain some residual negative pressure. Reportedly this may allow a small amount of carbon dust to be sucked back into an instrument.

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The question with no answer, suck or blow?

Clarence

Whatever she'll agree to.

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[jetdriven]

I sent my gyros in for overhaul and they had carbon dust in the bearings, and the bearings were worn out from that. They had 400 or 500 hours since the last overhaul, and a repeating pattern in the logs of such replacement intervals.  I installed the CV1J4 filter and it is getting darker, but the gyros seem to be doing fine at 400 and 500 hours.  So, I cant explain it, but I know it happens.

[rbridges]

19 minutes ago, jetdriven said:

I sent my gyros in for overhaul and they had carbon dust in the bearings, and the bearings were worn out from that. They had 400 or 500 hours since the last overhaul, and a repeating pattern in the logs of such replacement intervals.  I installed the CV1J4 filter and it is getting darker, but the gyros seem to be doing fine at 400 and 500 hours.  So, I cant explain it, but I know it happens.

Odd that it's only available for J,K and M models. 

[jetdriven]

Its on mine, minor alteration.  Technically its not an alteration at all,  its also in the J parts catalog.

[Andy95W]

2 hours ago, M20Doc said:

Not just the S-Tec, the Britain is the same.

Clarence

But the Brittain uses vacuum to actuate the controls, so no dice if the vacuum pump is out.

[Alan Fox]

3 hours ago, N1395W said:

But the Brittain uses vacuum to actuate the controls, so no dice if the vacuum pump is out.

As the Brittain guys always say , If you have a total electrical failure in IMC , you will crash wings Level....

[Marauder]

3 hours ago, N1395W said: But the Brittain uses vacuum to actuate the controls, so no dice if the vacuum pump is out.

As the Brittain guys always say , If you have a total electrical failure in IMC , you will crash wings Level....

That's funny! The STEC guys have a similar line. If you have a total vacuum failure in IMC, you won't crash wings level.

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[kmyfm20s]

In my score book, vacuum driven instrument or pump failure +5, electric anything 0.

[aviatoreb]

3 hours ago, kmyfm20s said:

In my score book, vacuum driven instrument or pump failure +5, electric anything 0.

What does +5 mean for a failure?

[kmyfm20s]

5 failures I recall but I think there another. 

[Hank]

6 hours ago, kmyfm20s said:

In my score book, vacuum driven instrument or pump failure +5, electric anything 0.

My 8-year experience is one (1) vacuum pump failure in VMC, one (1) total electrical failure in IMC. You pays your money and takes your chances.   Thus need to practice, often. 

[Loogie]

My experience w vacuum:. I kept getting the dummy low pressure light, Rapco dry pump had 800 hrs or so.  I fly IFR pretty regularly; my mech rec change the pump, which I did.   Dummy light came on again on a trip to upstate NY soon after new pump installed.  The ADI tumbled but HSI worked, VFR conditions during trip back from NY.  After some deeper trouble shooting we discovered rubber or plastic tubing after regulator had broken down due to age.  It would have been easier to detect if I had a vacuum gauge. 

Had all the tubing and filters replaced, added a vacuum gauge as well.  

I now now have a new pump, new tubes, new filters, and it works like a champ.

My back up is partial panel to VMC

second back up is FF ADI

Lesson: check your vacuum system tubing for any leaks and condition in addition to just replacing pumps!  If you have non metallic vacuum tubing greater than 20 yrs old, you are on borrowed time.

 

[neilpilot]

2 failures each, vacuum and electrical.  Both vacuum failures were in VFR, and never used Precise backup vacuum since sTec made them a non-event.  One of the electrical failures was on STAR into Dallas Love in actual.  I carry a handheld radio with external antennae connection and PTT accessory, and that saved the day getting into KDAL.

[Guest Mike261]

On November 26, 2015 at 11:17:14 AM, PTK said:

I applaud BK for the KI 300 which will enable the removal of the vaccum system altogether in my Mooney! 

http://www.bendixking.com/V4/KI-300

Aviation consumer has an article this month in the AHRS attitude indicators...myself, i will gladly fork over the five or six grand for the KI300. the current king indicator i have will need attention soon, and i can get rid of the vacuum pump, the back up electric pump, all the tubing and wiring and have a much more reliable unit that will tell me when it fails instead of rolling me into an unusual attitude. for me this thing is a no brainer.

mike

[aviatoreb]

6 minutes ago, Mike261 said:

Aviation consumer has an article this month in the AHRS attitude indicators...myself, i will gladly fork over the five or six grand for the KI300. the current king indicator i have will need attention soon, and i can get rid of the vacuum pump, the back up electric pump, all the tubing and wiring and have a much more reliable unit that will tell me when it fails instead of rolling me into an unusual attitude. for me this thing is a no brainer.

mike

Right - but it is not yet available.  Agreed it is beautiful though.

[Guest Mike261]

Just now, aviatoreb said:

Right - but it is not yet available.  Agreed it is beautiful though.

no, its not...it was to be certified in december, they now say february. maybe its vaporware, but i don't think so. have to hold out.

[Seth]

On 11/26/2015, 5:09:27, jetdriven said:

I dont see the value of depending on an iPad for emergency attitude information.  You turn the yoke, the iPad turns.  Then you're looking down at it or at it sitting on your lap.  I don't see how you're going to be able to control an airplane in IMC with that 

That's why mounting an iphone or an ipod touch sideways somewhere near the panel, not the yoke, is what I'll probably end up doing.  Similar  to what many posted here.  It gets it's signal from the Stratus 2, and then some sort of AHRS display will then show.  I'm thinking of mounting it where I currently have blank space right in front of the copilot seat - my wife would actually like that too.  Scan wise, it'll be annoying to look over that way, but it's a backup.  Just one of many ideas. A power source would be nice to not have to worry about the battery.

If Garmin came out with a portable display unit like the Aera 500/560 that also had Independence AHRS, now you've got something to go along with an Ipad.  An avaition product made by an aviation company - not certified for the panel of course, but if not "permanently" mounted, it could be a great emergency instrument.

 

 

 

-Seth

[mike_elliott]

Chris I practiced approaches just with the svt and no other equip. We did about four down to minimums at Roanoke with each one ending right over the numbers. It was as if I was flying vfr the display with svt was that good.

The G1000 SVT is sweet, just a bit on the pricey side at over 10AMU's.