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Vacuum failure


Alfredo

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Took off from Pompano destination Orlando 172 Mn 1:25 flight, IFR AT 500 feet and 6000 became clear

Final level 7000.

Arriving at the Orlando terminal I lost the attitude indicator, I looked at the vacuum pointer and confirmed it.the app asked to get down to 5000 and it started to get broken, at the same time I started to use the attitude indicator from the iPad and I activated the auxiliary vacuum pump , and also slowed down because it was already in yellow (165kt) and I thought it best to slow down to have less of a concern. The attitude indicator started to work, I immediately started to compare with the iPad and I saw that it was right ........... the pitch of the iPad was not level and from moving the iPad It  also stop work. And the auxiliary vacuum the attitude indicator stopped too.

At last I was monitoring climb speedometer and compass and soon after I was out of the clouds. I made a beautiful landing .......... and went to workshop and when they arrived they said that the AUXILIARY PUMP only works with a certain pressure of manifold. I tried to find spread sheet in various places on the subject but I did not think ........... you know something about it.

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43 minutes ago, Alfredo said:

Took off from Pompano destination Orlando 172 Mn 1:25 flight, IFR AT 500 feet and 6000 became clear

Final level 7000.

Arriving at the Orlando terminal I lost the attitude indicator, I looked at the vacuum pointer and confirmed it.the app asked to get down to 5000 and it started to get broken, at the same time I started to use the attitude indicator from the iPad and I activated the auxiliary vacuum pump , and also slowed down because it was already in yellow (165kt) and I thought it best to slow down to have less of a concern. The attitude indicator started to work, I immediately started to compare with the iPad and I saw that it was right ........... the pitch of the iPad was not level and from moving the iPad It  also stop work. And the auxiliary vacuum the attitude indicator stopped too.

At last I was monitoring climb speedometer and compass and soon after I was out of the clouds. I made a beautiful landing .......... and went to workshop and when they arrived they said that the AUXILIARY PUMP only works with a certain pressure of manifold. I tried to find spread sheet in various places on the subject but I did not think ........... you know something about it.

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You are not talking about an auxilary pump. It sounds like you are describing the Precise Flight standby vacuum system that works on pressure differential from the manifold pressure. You will need to fly a profile with the engine driven vacuum pump not connected and write down the corresponding MP & RPM settings to get you a desired vacuum and airspeed. Here is one I created for my plane. Since then, I have gotten vacuumless.

01b8378fda9efe371ddc8d298fc0311e0f15945119.thumb.jpg.a0e33bf31b54b07b24ceacd7c382c5f2.jpg

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Good job recognizing the problem and getting down to VFR right side up.

The BU vacuum does tap the intake manifold to pull vacuum. And you probably won't see the 5-6" produced by the primary vacuum pump. You should have a AFM supplement for the add on system that describes its operation and limitations. 

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7 minutes ago, Bob_Belville said:

so the higher the MAP the more vacuum

Actually, isn't it the reverse....the lower the MAP the more vacuum.  If you activate the Precise backup system, you may need to reduce the manifold pressure to maintain adequate backup vacuum.  BTW one reason I prefer the sTec as an autopilot is that, if my vacuum pump does fail, the autopilot is all electric and so it's function isn't impaired.

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1 hour ago, neilpilot said:

Actually, isn't it the reverse....the lower the MAP the more vacuum.  If you activate the Precise backup system, you may need to reduce the manifold pressure to maintain adequate backup vacuum.  BTW one reason I prefer the sTec as an autopilot is that, if my vacuum pump does fail, the autopilot is all electric and so it's function isn't impaired.

Yes. The Precise Flight system based on a manifold differential requires you to drop MP quite a bit. Especially if you are up at altitude.

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In my 88J I lost my vacuum pump twice both times IFR once at night, having a precise flight standby system works, I advised control notifying I needed to slow down according to the chart Chris depicted. Great idea to have it handy and close by. My new J at the time only had 69 hours on it’s the second system went within. 60 hours as well.

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The Precise flight SVS system is better than nothing, but by a very small margin given that you need to pull MAP to be lower than ambient pressure. They are far more useful in a NA aircraft and I've always wondered how they got approval for installation in turbo's. But I guess at least you get something back for the approach once you get down low. Most turbo's have the electric standby vacuum system. But these days glass is the better direction.

Here is a copy of the AFMS - which you can find either on Mooney's site or from Precise.

But remember on your way down you still have the electric turn and bank, keep the wings level and just reduce power to come down slowly in control. I only say that because we're still losing pilots from vacuum loss emergencies - our last one was an ATP just a couple years ago in a Bonanza that perished when he broke up the aircraft after less than a 2000' of descent from over stressing the airframe.

AFMS Precise SVS.pdf

Edited by kortopates
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@Alfredo,

Glad you figured out your issue and got down safely. Also glad you joined the forum and started asking good questions, as I learn along with you from the tremendous knowledge-base of MS. I can't speak specifically to your alternate vacuum issue but this 

2 hours ago, kortopates said:

But remember on your way down you still have the electric turn and bank, keep the wings level and just reduce power to come down slowly in control. I only say that because we're still losing pilots from vacuum loss emergencies - our last one was an ATP just a couple years ago in a Bonanza that perished when he broke up the aircraft after less than a 2000' of descent from over stressing the airframe.

is why I replaced the electric turn and bank coordinator with a Garmin G5. I replaced the T&B due to my observation of the AI and the T&B during vacuum failure, while on a VFR flight. The AI was down right dangerous and the T&B bounced all over the place due to turbulence. I believe the Bonanza pilot Paul @kortopates mentioned had a T&B in place and still perished.

As others have mentioned on this thread, it sounds like there is an effective way to use your installed alternate vacuum source in your recent scenario but as @Marauder pointed out, it may be safer/better to go a different route. E.g. approved EFIS AI replacements or other dual function products that provide AI functionality such as the AV-20 or AV-30.

Just adding my 2¢ to a good conversation. 

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Glad you are still with us, Alfredo..!

  • Loss of vaccuum In IMC is an emergency...
  • we lost a local Bonaza pilot who descended into clouds before losing control...
  • To use the precise flight system you need some skill/knowledge, or be an engineer...

 

We need to be intimately familiar with our back-up systems.  

  • Vacuum has a nearly planned outage every 500 hours on average... and likely to suffer an outage when new...
  • The precise flight device that uses engine vaccuum is notorious.... It doesn’t work anywhere near WOT....
  • Alfredo slowed down by selecting a lower MP, and thus made the precise flight system actually work.... (surprise)
  • There is probably a plaque or POH pages that go with that system...

 

Relying on a back-up system that is portable and not attached solidly to anything just sounds like 1/2 of what you need, when you need it...

How was your TC during all of this?

Start considering your alternatives now... there are plenty of better systems available for not  many AMUs...

Vaccuum sucks... I have two vacuum pumps that get tested every flight.

Modern systems have gone to dual alternators... and lots of batteries...

 

If anyone still has one of these Precise flight back-up systems... the knob on the instrument panel is a hint.... if you do..  get up to speed with its operation... and plan an update... a solid Plan B.  :)

 

Flying used to be considered risky... there was no MS to share real experience... the accident would have been blamed on failed equipment...  Why accept an accident...  be proactive.  Actively seek to avoid challenges that can turn for the worse...

i get a fuzzy feeling knowing my life is depending on an iPad and it’s blue tooth connection....  Apple is working on this as part of using the Iwatch and iPhone as a pseudo medical device....

 

Nice work, Alfredo!  Great Pirep.

Best regards,

-a-

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13 hours ago, neilpilot said:

Actually, isn't it the reverse....the lower the MAP the more vacuum.  If you activate the Precise backup system, you may need to reduce the manifold pressure to maintain adequate backup vacuum.  BTW one reason I prefer the sTec as an autopilot is that, if my vacuum pump does fail, the autopilot is all electric and so it's function isn't impaired.

Pressure differential....   low MP caused by the throttle plate being more closed...

At altitude... low MP with WOT will not generate the needed vacuum...

Its a hokey system great for Jedi knights.... and Jedi Marauders... :)

See the work it took for Marauder to know the conditions it takes to make his work.

Ordinary pilots won’t have the ability to test and train using the system without disconnecting the vaccuum system...

 

This system may not work good enough at high altitude over mountains... worse when fully loaded...

 

PP thoughts only, not a mechanic...

Best regards,

-a-

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I have a PF "standby vacuum system," and it's just a quirky relic from a bygone era. I don't intend ever to use it for anything other than entertainment purposes. (See, kids, we used to have to walk to school, uphill both ways..)

Today, you can spend 0.8 AMUs for a Dynon D3 with SV, battery backup, and no install costs. And it actually decreases your workload in an unexpected partial-panel situation, rather than increase it. 

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3 hours ago, RLCarter said:

Stay/get proficient on partial panel, as much as I love my iPad, it would be my last resort for keeping the aicraft right side up

We don’t practice “partial panel” during recurrency training any longer.  

With multiple AHRS-driven attitude displays, several of them battery backed, the loss of all attitude reference is too unlikely to merit any training time.  

The Turn Coordinator has been removed, as is allowed. We still have to keep the kerosene compass, useless dead weight.  

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The AHRS attitude indicator in the AV-20 sold by Aerovonics seems to be rock solid and battery backed.   I've compared it against my gyro instrument and it always agrees pretty closely.  The AV-20 is a clock with a bunch of cool lagniappe (look it up).   Pretty awesome for what it costs.

 

 

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8 minutes ago, mike_elliott said:

I do

The instructor who taught me for my IR does partial panel for a (B)FR and will also throw one in for an IPC.

And when my Aspen and autopilot got into a disagreement last year when I was in the middle of a 5,000' cloud deck, I was glad he did.

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1 hour ago, Fred₂O said:

The AHRS attitude indicator in the AV-20 sold by Aerovonics seems to be rock solid and battery backed.   I've compared it against my gyro instrument and it always agrees pretty closely.  The AV-20 is a clock with a bunch of cool lagniappe (look it up).   Pretty awesome for what it costs.

 

 

+1

I'll do the AV-20 about 20 seconds after it's certified to replace my factory clock. 

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The instructor who taught me for my IR does partial panel for a (B)FR and will also throw one in for an IPC.

And when my Aspen and autopilot got into a disagreement last year when I was in the middle of a 5,000' cloud deck, I was glad he did.

Absolutely, partial panel training should be dependent on your installed equipment. Without backup ADHRs, your partial panel will be based on the legacy instruments that not enough pilots maintain proficiency with.

Those of us with backup glass, (not subject to being taken out entirely by a pitot heat failure), and understand our avionics equipment failure modes, will be merely inconvenienced.

 

 

 

Sent from my iPhone using Tapatalk

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I think “partial panel” is a misnomer for those of us with redundant glass panels. Instead of practicing partial panel, my IPCs have become an exercise in understanding the failure mode and moving to an alternate panel.

We can fail my Aspen PFD, have reversion mode kick in and move it to the MFD. If both failed, then the L-3 ESI-500 becomes primary. Beyond that, now we are into using the turn coordinator and an iPad AHRS software solution.

All of this is far removed from losing the attitude indicator and moving to what we all learned as the partial panel.


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3 hours ago, Oldguy said:

The instructor who taught me for my IR does partial panel for a (B)FR and will also throw one in for an IPC.

And when my Aspen and autopilot got into a disagreement last year when I was in the middle of a 5,000' cloud deck, I was glad he did.

I have 4 AHRS systems, two on their own battery backup.  

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I should add that how the autopilot plays into this also comes into consideration. With my Aspen in reversion mode, I am able to switch the autopilot over to the MFD for control. Again, knowing what to do in the failed scenario is the key.

dc3ccc24584e0a824fe648829459e16e.jpg


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34 minutes ago, Marauder said:

I think “partial panel” is a misnomer for those of us with redundant glass panels. Instead of practicing partial panel, my IPCs have become an exercise in understanding the failure mode and moving to an alternate panel.

Instead of "partial panel" should we call this "glass half full"?;)

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23 hours ago, Jerry 5TJ said:

We don’t practice “partial panel” during recurrency training any longer.  

With multiple AHRS-driven attitude displays, several of them battery backed, the loss of all attitude reference is too unlikely to merit any training time.  

The Turn Coordinator has been removed, as is allowed. We still have to keep the kerosene compass, useless dead weight.  

That’s all fine and dandy if your glass with back batteries/ units but the original post sounds like he has steam gauges

Edited by RLCarter
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RLC,

The important part of this technology thread...

Is to know the plan of...

  • what backs up what...
  • how to use it...
  • whether it is all glass, part glass, or fully mechanical....

When the vac pump dies, you may get a couple of minutes to be on Plan B before the gyro winds down...

Not enough time to break out a POH to skim and decide on the next steps...

 

The precise flight device has pretty well been forgotten in the how to use it aspect.... without the outline that Marauder has shown above... a pilot might be SOL at high altitudes above rocks or by accidently keeping too much throttle in... this is what the OP learned after the flight...

An engineer with a passion for engines might do OK with this thing... but, A D3 mounted in the panel might be a better choice for everyone... and cost a whole lot less than an engineering degree...  :)

As for Plans B....

  • TnBs these are terrible designs for bouncing around in the bumps...
  • TCs are better by their design for the bumps... but wear over time... and only misbehave in the bumps....
  • Precise flight systems have their known issues...
  • Back up electric vac pumps are pretty good... but we have seen some failures of these systems too in the last couple of years... failures before use...
  • Electronic back up attitude indicators with their own batteries are looking pretty sweet compared to the rest of this list.

PP thoughts only...

Best regards,

-a-

 

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