Would like to ditch my vacuum system

[M20 Ogler]

AI and DG in my M20C are both starting to act a little funny. I’d like to replace them with G5s or something but have some concerns. 

Mark at TopGun once told me without the wing leveler the plane is not IFR anymore because it was certified with the wing leveler. Does that mean I need an autopilot up grade too? Yikes $$$

Also what do people do about their vacuum powered step retract? Can I just fix it in place? How much speed does that step cost me?

[Utah20Gflyer]

I didn’t see the PC system on the required equipment list for IFR so I don’t see why removing it would make an airplane VFR only.  Plus based on that logic even if you did install an auto pilot you still wouldn’t have the PC system.  You also wouldn’t have the original radios the plane came with.   So to summarize the PC system isn’t on Mooneys required equipment list, it’s not on the minimum equipment list in the FARs so you would be good to go.

I actually just removed my vacuum system after installing a second GI 275.  The answer about the step is to convert to electric which I did.   You can find the electric step conversion in the vendor section of the forum.  

[UteM20F]

We recently removed the vacuum system in our F.  We don't have the PC system and our AP is inop, but we are still certified IFR.  A big advantage of removing the vacuum system and heavy instruments is the useful load increase.

The electric step wasn't very expensive.  We wired ours to the landing gear.  Interestingly, the electric step operates very slowly.

We're in Provo if you want to see how it looks.

Ute

[Utah20Gflyer]

7 minutes ago, UteM20F said:

We recently removed the vacuum system in our F.  We don't have the PC system and our AP is inop, but we are still certified IFR.  A big advantage of removing the vacuum system and heavy instruments is the useful load increase.

The electric step wasn't very expensive.  We wired ours to the landing gear.  Interestingly, the electric step operates very slowly.

We're in Provo if you want to see how it looks.

Ute

Lol, yeah that electric step is really slow but I just deploy it as part of my engine shut down procedure, by the time I have everything shut down and tach time recorded, etc it’s ready to go.  Overall, very happy with it. 

[McMooney]

G5's are being installed in my bird as we speak which leaves the brittain as the only thing using the vac/stand by vac systems.

my step somehow fell off the plane a few years back.

[Robert Hicks]

Mark at Topgun is 100% wrong. 

[Pasturepilot]

I’ve got a 65 C model. The gyro for my PC is in the tail, so I’m able to keep the PC active with G5s replacing both gyros in the panel. That way my step still retracts too. 
 

if you’ve got a later system with the turn coordinator running the show, I see no reason you couldn’t keep the vacuum for the TC and the PC system, you’d just need to cap some vacuum lines. 

[carusoam]

4 hours ago, Robert Hicks said:

Mark at Topgun is 100% wrong. 

Point well taken…. Or did something not clearly get explained, or understood…?

The GA version of MELs (minimum equipment list) are in our POHs…

The wing levelers and APs are nice, but are not usually required equipment for IFR flight… (I just checked the M20R POH) 

 

Going all electric is pretty common lately…

Vacuum operated steps have been replaced in the hundreds around here… find @takair Rob for details… he has a nice website for additional info…

 

The biggest challenge is for people with vac operated speed brakes… they require exchanging units… with different foot prints…

 

Keep in mind… the wing leveler in Mooneys became standard in 1965… for a reason.

Human beings flying in IMC tend to need something to hold the wings level every now and then…. 

 

Sooooo… go electric with the instruments…. Keep the vac system for the Brittain system… there is a complete system around here recently…

If you fly VFR only, the wing leveler is nice to have… not so much a safety of flight issue as flying in IMC…. 
 

PP thoughts only, not a CFII….

Best regards,

-a-

 

[carusoam]

4 hours ago, Pasturepilot said:

I’ve got a 65 C model. The gyro for my PC is in the tail, so I’m able to keep the PC active with G5s replacing both gyros in the panel. That way my step still retracts too. 
 

if you’ve got a later system with the turn coordinator running the show, I see no reason you couldn’t keep the vacuum for the TC and the PC system, you’d just need to cap some vacuum lines. 

See if we are saying the same thing…   

Brittain wing leveler system….

1) Uses a gyro to control the system…. Tail mounted in 1965 and older… electric driven.

2) Uses vacuum to operate the servos… those rubber bladder devices in a plastic can… 

3) To have an operating wing leveler… the vac is going to be required…

 

vacuum pumps aren’t too horrible to keep active…

They are terrible for powering primary flight instruments in IMC, with their low MTBF rates….

But, for powering a wing leveler, until a newer AP can be installed….

Keep the vac system. 

Best regards,

-a-

[vorlon1]

11 hours ago, McMooney said:

my step somehow fell off the plane a few years back.

Wait, what?

[Pasturepilot]

5 hours ago, carusoam said:

See if we are saying the same thing…   

Brittain wing leveler system….

1) Uses a gyro to control the system…. Tail mounted in 1965 and older… electric driven.

2) Uses vacuum to operate the servos… those rubber bladder devices in a plastic can… 

3) To have an operating wing leveler… the vac is going to be required…

 

vacuum pumps aren’t too horrible to keep active…

They are terrible for powering primary flight instruments in IMC, with their low MTBF rates….

But, for powering a wing leveler, until a newer AP can be installed….

Keep the vac system. 

Best regards,

-a-

We’re pretty close to being on the same page. I think 65 may be the only year with the gyro in the tail.  We can ditch all the gyro instruments; other years would have to keep the turn coordinator. 
 

But yes- keeping the vacuum pump in place to run only the PC system seems like a reasonable compromise for those of us unwilling to spend a LOT of money on an autopilot. The PC system gets a lot of hate but it’s simple, cheap, and not that difficult to maintain if you study it a little while. 
 

7 minutes ago, vorlon1 said:

Wait, what?

A few Mooney steps steps “fell off” after owners or mechanics removed their fasteners in the search for an additional half knot. 

[vorlon1]

Oh, OK. 

[takair]

If you fly IFR regularly, consider that the PC can be a huge workload reduction and potential lifesaver.  If you are not replacing it with a new autopilot, I would seriously consider keeping the system at the small expense of replacing a vacuum pump every 500 hours.  Consider that Garmin invested big and folks spend big to have an autopilot that has a blue button to level the wings.  Your Brittain PC was doing it in 1965…and before.  As much  as I like selling electric step kits, I still think that some form of autopilot is more important for true IFR operations.  By the way, the PC is not required for IFR by the Mooney TC, but it is a true enhancement and Mooney thought enough of it to include it in 1965…. 

[S.C.]

As many have stated, it’s a process. I removed the vacuum system when the AI and HI went for dual g-5’s and added the electric step and have had zero regrets.  The autopilot is the next step and will soon be upgraded too.  I think it is investing in the future of the airplane and the integration of components from the same era really reduces my workload.  
 

I don’t  recall exactly  how much removing the vacuum system saved me in weight but every little bit helps.  

[redbaron1982]

23 hours ago, UteM20F said:

A big advantage of removing the vacuum system and heavy instruments is the useful load increase.

How much of a useful load increase it's expected by removing completely the vac system, the AI and DG? I read that is not much.

[UteM20F]

21 hours ago, redbaron1982 said:

How much of a useful load increase it's expected by removing completely the vac system, the AI and DG? I read that is not much.

It's not likely to be apples to apples for your situation, as we also removed all the antique engine instruments and fuel gauges, replaced all lights (including removing the coffee grinder) with LED, and went glass, replacing all radios.  We lost over 20 lbs.

Ute

[tony]

I suggest you read and adhere to note 24 in the TDCS (2A3), then you're good to go.

Edited March 12, 2023 by tony

[Fly Boomer]

4 minutes ago, tony said:

I suggest you read and adhere to note 24 in the TDCS (2A3), then you're good to go.

Ten or twelve people have posted in this topic.  Who where you responding to?

[carusoam]

The best reason to remove the vac system…

1) vac pump failure rate is expected to be high beyond 500hrs….

2) When they fail… pilots have difficulty identifying and dealing with the problem….

3) Preparation for failure… some people are still using the TC as a back-up instrument…

4) Good TCs are still crummy AI substitutes… depending on partial panel skills and currency…

5) Bad TCs wear without giving much notice…

6) A bad TC can’t be followed very easily in bumpy weather…

7) New electronic devices make great instruments… but make sure they are both operating independently of each other… two separate Adhars devices to feed separate indicators…. 

8) Know the instrument manufacturers are happy to sell one adhars device to feed two instruments…. That is not enough redundancy for Mooney pilots flying in IMC…

9) This is really important for flying in IMC… not so much if you can stay in VMC all of the time… 

10) Recent aviation history has shown these failures in real life… not just theory.

PP thoughts only, not a CFII…

Best regards,

-a-

[rbp]

11. I gained 50# of useful load 

[AIREMATT]

On 3/9/2023 at 7:30 AM, takair said:

If you fly IFR regularly, consider that the PC can be a huge workload reduction and potential lifesaver.  If you are not replacing it with a new autopilot, I would seriously consider keeping the system at the small expense of replacing a vacuum pump every 500 hours.  Consider that Garmin invested big and folks spend big to have an autopilot that has a blue button to level the wings.  Your Brittain PC was doing it in 1965…and before.  As much  as I like selling electric step kits, I still think that some form of autopilot is more important for true IFR operations.  By the way, the PC is not required for IFR by the Mooney TC, but it is a true enhancement and Mooney thought enough of it to include it in 1965…. 

It is definitely better than nothing at all since most of our older models don’t have aileron or rudder trim installed as standard equipment. At least if the PCS is working you can let the yoke go and keep the plane pointed in the same direction without rolling off one way or the other.