Failed Vacuum Pump

[markejackson02]

There's no harm in flying (VFR of course) with a failed vacuum pump, is there?

 

My mechanic is out of town and I need to get the plane to and from a spot an hour away.

 

 

[Smiles201]

As a side note,I found out the hard way that it is recommended to vacuum out the system after a pump failure to minimize the possibility of gyro failure after pump failure and the consequent ingestion of broken pump pieces.

[Andy95W]

PROBABLY no harm done. It probably sheared the shaft, like it's supposed to do. But you can't be sure.

Also, your gyros are designed to spin, if you have a hard landing or put any other kind of stress on your instruments, you could damage the bearings.

Would I recommend it? Of course not.

Would I fly my own airplane like that, perhaps to get it home so I can repair it? Probably.

[Dale Logsdon]

It won't harm a thing, unless you find IFR weather.

[rbridges]

There's no harm in flying (VFR of course) with a failed vacuum pump, is there?

 

My mechanic is out of town and I need to get the plane to and from a spot an hour away.

 

mine went out 30 minutes from home on a bright sunny day.  Didn't realize it until I saw the low vac light.  No harm done in my case.  As Andy said, the shaft sheared.

[Alan Fox]

Since the air to the gyros is not from the pump side , and comes from the filter , a catastrophic pump failure will not put debris into the instruments , it could affect the mew pump , but extremely unlikely....

[Robert C.]

Well, probably wouldn't hurt to see if there is a MEL in your POH.

 

Otherwise remember the FARs based checklist item?:

 

VFR day (TOMATOES AFLAME) (91.205 b.)

 

Tachometer

Oil pressure gauge

Magnetic compass Airspeed indicator

Temperature gauge (liquid cooled engines only)

Oil temperature gauge

ELT

Seatbelts

Anti-collision lights

Fuel gauges

Landing gear position indicator

Altimeter

Manifold pressure gauge (for each altitude engine)

Emergency equipment

 

Nothing that works off vacuum pump on that list so at least you are legal

[N201MKTurbo]

Since the air to the gyros is not from the pump side , and comes from the filter , a catastrophic pump failure will not put debris into the instruments , it could affect the mew pump , but extremely unlikely....

I've never had it happen, but every instrument tech I've talked to has told me to clean the vacuum system after a pump failure. Also the directions in the new pump says the warranty is void if you don't clean the vacuum system after a pump failure.

FWIW, I only clean it back to the regulator. It only takes a few minuets.

[flyboy0681]

mine went out 30 minutes from home on a bright sunny day.  Didn't realize it until I saw the low vac light.  No harm done in my case.  As Andy said, the shaft sheared.

 

About a year ago mine also went out about 30 miles from home. The light did come on as the AI ever so slowly turned over on its side. I also knew from previous experience to instantly disengage the autopilot.

[rbp]

definitely read 91.213.  Once you've determined that the instruments are not required, you have to deactivate (EG pull the breaker) and placard them. I would also placard the suction gauge.

 

(3) The inoperative instruments and equipment are--
(i) Removed from the aircraft, the cockpit control placarded, and the maintenance recorded in accordance with Sec. 43.9 of this chapter; or
(ii) Deactivated and placarded "Inoperative." If deactivation of the inoperative instrument or equipment involves maintenance, it must be accomplished and recorded in accordance with part 43 of this chapter; and
 

(4) A determination is made by a pilot, who is certificated and appropriately rated under part 61 of this chapter, or by a person, who is certificated and appropriately rated to perform maintenance on the aircraft, that the inoperative instrument or equipment does not constitute a hazard to the aircraft. An aircraft with inoperative instruments or equipment as provided in paragraph (d) of this section is considered to be in a properly altered condition acceptable to the Administrator.

 

 

 

http://www.flightsimaviation.com/data/FARS/part_91-213.html

[N601RX]

At the point the pump fails all the gyro cans are at under a vacuum.  Additionally if you have the vac powered step and Brittain PC system all these cans are under a vacuum.  Essentially all theses devices become a network of storage tanks for the vacuum.  When the pump stops the stored up vacuum pulls air in from the pump as it is bled down. There is also the possibility that the cabin air is at a lower pressure than the area around the vac pump.  If this is true then air will continue to flow from the pump back into the instruments.  That's the reason for the inline filter between the pump and regulator.

 

https://www.aircraftspruce.com/catalog/inpages/Inline_airfilter.php

[jetdriven]

All the gyro bearings end up with carbon dust in them which necessitates overhaul. It can only come from one place, the vacuum pump. Every shutdown the process N601RX describes will happen. The 1J4 filter prevents that dust.

[Andy95W]

At the point the pump fails all the gyro cans are at under a vacuum.  Additionally if you have the vac powered step and Brittain PC system all these cans are under a vacuum.  Essentially all theses devices become a network of storage tanks for the vacuum.  When the pump stops the stored up vacuum pulls air in from the pump as it is bled down. There is also the possibility that the cabin air is at a lower pressure than the area around the vac pump.  If this is true then air will continue to flow from the pump back into the instruments.  That's the reason for the inline filter between the pump and regulator.

 

https://www.aircraftspruce.com/catalog/inpages/Inline_airfilter.php

Nice explanation, thanks.

[N601RX]

Here is a video of my inline filter after a DG failure.  It protects the instruments from pump failure and pump from instrument failure. The filter was still clean 5 hrs before the DG failed. At the time it failed all the lines and filters were less than 1 year old so I assume most of the stuff came from the DG as it failed.

Vac Filter.MOV

[Marauder]

Here is a video of my inline filter after a DG failure. It protects the instruments from pump failure and pump from instrument failure. The filter was still clean 5 hrs before the DG failed. At the time it failed all the lines and filters were less than 1 year old so I assume most of the stuff came from the DG as it failed.

Want to hear a funny story about those filters? They are expensive to start;

http://www.aircraftspruce.com/catalog/inpages/Inline_airfilter.php

I normally would order many of the consumables before my annual and bring them to the mechanic. Well, I get these filters and pull them out of the box. I noticed the label on the filter was loose, so I pulled it back and lo and behold there is a Fram G2 label on the filter: http://www.walmart.com/ip/Fram-Fuel-Filter/16817247

Price difference (at the time)? 40X more expensive for the certified one.

I notice the design is the same but the unit looks a bit different.

[rbridges]

About a year ago mine also went out about 30 miles from home. The light did come on as the AI ever so slowly turned over on its side. I also knew from previous experience to instantly disengage the autopilot.

 

that was a learning experience for me.  I didn't realize how slowly things would shift when the vacuum was lost--I thought it would be more sudden.  

[Robert C.]

My experience with a vacuum failure came when i was a freshly minted PPL on one of my first cross-country flights (post-PPL). I was (still am) working very hard at persuading my wife that this is a useful hobby.

 

So I'd booked the club Archer and we'd flown up to Lake Placid on a beautiful day, took the trolley into town, had a lovely lunch, walked around, etc.

 

Get back to the airport, start her up (the Archer that is...get your mind out of the gutter please), and as I'm doing the cockpit checks realize that the vacuum pump had packed up. No DG and a tilted AI. Even I was smart enough to know that meant no A/P.

 

So I break out in a cold sweat, 1.5 hrs away from home on a weekend day in the club plane. Can I fly it home? Is it legal, is it safe? Do I tell my wife? etc.

 

Of course I completely forget that the Archer has a backup vacuum pump knob that I can pull

 

So i decide not to say anything to my wife for fear of scaring her off. Uneventful flight home, good practice hand flying all the way. That evening I dutifully record the squawk in the squawk book and e-mail the maintenance officer for that particular Archer.

 

Next day Club President acknowledges the squawk and in his e-mail back asks me how that backup vacuum pump worked for me....oops 

 

"I learned from that" !

[jetdriven]

Want to hear a funny story about those filters? They are expensive to start;http://www.aircraftspruce.com/catalog/inpages/Inline_airfilter.php

I normally would order many of the consumables before my annual and bring them to the mechanic. Well, I get these filters and pull them out of the box. I noticed the label on the filter was loose, so I pulled it back and lo and behold there is a Fram G2 label on the filter: http://www.walmart.com/ip/Fram-Fuel-Filter/16817247

Price difference (at the time)? 40X more expensive for the certified one.

I notice the design is the same but the unit looks a bit different.

That Fram filter in no way is the same is the CV1J4 filter except it's clear and has a paper element. I think you're confusing the Brittain vacuum system filter with a similar Fram filter that is nearly the same thing.

[jetdriven]

My experience with a vacuum failure came when i was a freshly minted PPL on one of my first cross-country flights (post-PPL). I was (still am) working very hard at persuading my wife that this is a useful hobby.

So I'd booked the club Archer and we'd flown up to Lake Placid on a beautiful day, took the trolley into town, had a lovely lunch, walked around, etc.

Get back to the airport, start her up (the Archer that is...get your mind out of the gutter please), and as I'm doing the cockpit checks realize that the vacuum pump had packed up. No DG and a tilted AI. Even I was smart enough to know that meant no A/P.

So I break out in a cold sweat, 1.5 hrs away from home on a weekend day in the club plane. Can I fly it home? Is it legal, is it safe? Do I tell my wife? etc.

Of course I completely forget that the Archer has a backup vacuum pump knob that I can pull

So i decide not to say anything to my wife for fear of scaring her off. Uneventful flight home, good practice hand flying all the way. That evening I dutifully record the squawk in the squawk book and e-mail the maintenance officer for that particular Archer.

Next day Club President acknowledges the squawk and in his e-mail back asks me how that backup vacuum pump worked for me....oops

"I learned from that" !

A couple things. One. The carbon dust from the gyro can spell an early demise of the vacuum gyros. Many planes have to have the gyros overhauled after a vacuum failure if they continue to fly it. So you get home but may ruin $1,500 Worth of gyros to do it.

Second, if it's a Precise flight vacuum system, these use vacuum in the intake manifold for vacuum. At takeoff and full, or nearly full throttle, they don't provide any vacuum. Could make the difference if IMC or at night.

[cliffy]

Flying with inoperative EQUIPMENT AND/OR INSTRUMENTS is not as simple as first meets the eye. Without an MEL specifically written and approved for the particular airplane (by N number) strictly speaking if it isn't working you can't fly it. This can even be stretched to include the cigar lighter if you have one. The rule says "ALL installed equipment must be operating OR differed by the use of an MEL OR removed/secured/ and noted in the maintenance log book (including any weight and balance calculations needed). Whether or not harm would come to the inop equipment has no bearing on the issue of legality. Now, that being said, unless you get ramped or have an accident who's to know BUT do you want to take that chance? Also if you make note of the failure in your log book and then make another flight before you get it fixed it's in your books and can be found at any time. Again, is it worth the exposure? See Sec (a) below:

Inoperative instruments and equipment.

Sec FAR 91.213 Inoperative Instruments and Equipment

(a) Except as provided in paragraph (d) of this section, no person may take off an aircraft with inoperative instruments or equipment installed unless the following conditions are met:

(1) An approved Minimum Equipment List exists for that aircraft.

(2) The aircraft has within it a letter of authorization, issued by the FAA Flight Standards district office having jurisdiction over the area in which the operator is located, authorizing operation of the aircraft under the Minimum Equipment List. The letter of authorization may be obtained by

written request of the airworthiness certificate holder. The Minimum Equipment List and the letter of authorization constitute a supplemental type certificate for the aircraft.

[cliffy]

I should have added that it makes no difference if you have a stby system or not. Be it Precise Flight intake vacuum system or a real electric stby system. The main vacuum pump has failed. That constitutes a failed piece of "equipment" that needs to be fixed or differed by MEL.

As was noted, the Precise Flight stby system will not work at full throttle and/or higher altitudes. In its own paperwork on "Limitations" it can not be used for departure as the primary vacuum source.

It all boils down to how much exposure you want at legalities and now that it is posted on a public website your intentions to knowingly break the FARs will be seen by many. Who knows if the Feds monitor this website? I certainly don't. Your exposure is even more now.

Not telling you what to do but just bringing up what the realities of the action are for your consideration before you do it.

[Robert C.]

My ELT failed its inspection recently. The AP placarded it inop, we entered in the log book as inop and then I kept on flying till i had a new ELT bought and installed.

 

As the ELT (and the AI/vacuum pump) aren't required for VFR flight that would make everything perfectly legal right? If I'm not mistaken many aircraft don't have a MEL so then you have to go on what the FARs define as minimum (which is different for for VFR (tomatoes aflame) and/or IFR).

 

Am I missing something?

 

Robert

[cliffy]

ELTs come under FAR 91.207 Removing them and operating the airplane is allowed as long as it is done IAW 91.207 (shown below). There are specific entries that have to be made in the log book, a placard must be installed in full view of the pilot and it can not operate longer than 90 days in that condition.

As far as instruments required for IFR or VFR flight, they are specific for that condition of flight BUT if they are installed (IFR instruments) they must be in good working order, They can not be just sitting in the panel INOP even if you are flying VFR only. The FAR on "INOP Equipment" takes control. Say you have an ADF or an Autopilot that doesn't work- LEGALLY speaking if you fly it that way you are in violation of the FARs. Now we all know that there are many planes flying with in just that condition BUT it is still against the FARs to do it. Ask yourself this, "would you take a Check Ride with a Fed as the Examiner, in your airplane in that condition?" Like I said, "how much legal exposure are you willing to accept?"

(10) An aircraft during any period for which the transmitter has been temporarily removed for inspection, repair, modification, or replacement, subject to the following:

(i) No person may operate the aircraft unless the aircraft records contain an entry which includes the date of initial removal, the make, model, serial number, and reason for removing the transmitter, and a placard located in view of the pilot to show “ELT not installed.”

(ii) No person may operate the aircraft more than 90 days after the ELT is initially removed from the aircraft; and

[Andy95W]

.Sec FAR 91.213 Inoperative Instruments and Equipment(a) Except as provided in paragraph (d) of this section, no person may take off an aircraft with inoperative instruments or equipment installed unless the following conditions are met:(1) An approved Minimum Equipment List exists for that aircraft.(2) The aircraft has within it a letter of authorization, issued by the FAA Flight Standards district office having jurisdiction over the area in which the operator is located, authorizing operation of the aircraft under the Minimum Equipment List. The letter of authorization may be obtained bywritten request of the airworthiness certificate holder. The Minimum Equipment List and the letter of authorization constitute a supplemental type certificate for the aircraft.

The critical portion of this regulation, unless the Mooney in question actually has an MEL (which is highly unlikely) is the paragraph (d) you noted above:

(d) Except for operations conducted in accordance with paragraph (a) or © of this section, a person may takeoff an aircraft in operations conducted under this part with inoperative instruments and equipment without an approved Minimum Equipment List provided—

(1) The flight operation is conducted in a—

(i) Rotorcraft, non-turbine-powered airplane, glider, lighter-than-air aircraft, powered parachute, or weight-shift-control aircraft, for which a master minimum equipment list has not been developed; or

(ii) Small rotorcraft, nonturbine-powered small airplane, glider, or lighter-than-air aircraft for which a Master Minimum Equipment List has been developed; and

(2) The inoperative instruments and equipment are not—

(i) Part of the VFR-day type certification instruments and equipment prescribed in the applicable airworthiness regulations under which the aircraft was type certificated;

(ii) Indicated as required on the aircraft's equipment list, or on the Kinds of Operations Equipment List for the kind of flight operation being conducted;

(iii) Required by § 91.205 or any other rule of this part for the specific kind of flight operation being conducted; or

(iv) Required to be operational by an airworthiness directive; and

(3) The inoperative instruments and equipment are—

(i) Removed from the aircraft, the cockpit control placarded, and the maintenance recorded in accordance with § 43.9 of this chapter; or

(ii) Deactivated and placarded “Inoperative.” If deactivation of the inoperative instrument or equipment involves maintenance, it must be accomplished and recorded in accordance with part 43 of this chapter; and

(4) A determination is made by a pilot, who is certificated and appropriately rated under part 61 of this chapter, or by a person, who is certificated and appropriately rated to perform maintenance on the aircraft, that the inoperative instrument or equipment does not constitute a hazard to the aircraft.

An aircraft with inoperative instruments or equipment as provided in paragraph (d) of this section is considered to be in a properly altered condition acceptable to the Administrator.

--------------------------------------------------------------------------------

Of that, the critical portion is (3) (ii) which simply states deactivated and placarded. Since the vacuum pump is inop., deactivation was successful and the vacuum instruments just have to be placarded inop. Since the vacuum pump breaking did not require any maintenace, you don't even have to make a logbook entry, according to this subparagraph.

Perfectly legal. The only potential hassle with the FAA is included in (4), above about whether the inoperative equipment (in this case the vacuum pump) "does not constitute a hazard to the aircraft". How do you determine it sheared it's shaft, or was it something more significantly hazardous?

[cliffy]

I don't think one would get away by saying the vacuum pump failed (no vacuum showing on the gauge) and that in itself was "deactivation". You would be operating an engine with a failed component attached to the gear case without any investigation of just what failed. Was it the pump? Was it a failed or blocked hose? Just what was it? What failed was the pump, how did you deactivate that? You would be making an 'assumption" not based on fact. Now if it was the pump drive that failed, why did it fail? Internal vane failure? Who knows but you still have pieces spinning in close contact with each other on a gear case. Don't think any Fed would by off on leaving the pump in place and calling it "deactivated". Deactivation in this context requires some kind of action not just a static or passive concurrence that the part doesn't work. Now if the pump was removed the vacuum system will be "deactivated" and can be placarded as such. Along with anything connected to the vacuum system- vacuum step, autopilot, roll stability system, vacuum gauge and lights, etc.