Lost my vacuum pump yesterday

[Earl]

Fortunately for me I was in VFR conditions even though on an IFR flight plan.  Very interesting how it manifested itself. 

I was climbing to an assigned altitude and had the autopilot engaged.  However, the plane would not climb and every time I pushed the up button on the autopilot it would climb for a short while and then begin to lower the nose as the artificial horizon wound down.  If I had been in the clouds I would not have had the visual clues and at some point would have only noticed that the artificial horizon said I was climbing at 15 degree attitude but the VSI would have shown a descent, the altimeter would be going down etc.  It did keep the wings level initially but it would have been a real challenge had I not noticed the loss of vacuum.  I would say it took me less than 30 seconds to notice the flashing High/Low Vac Light and then I saw that the pressure was zero.  I engaged my standby vacuum and it returned to normal but since I was in VFR conditions I shut off the standby and covered the artificial horizon and finished my flight.  By the way, this was the longest flight I have flown in a while with no autopilot and it was good to have to focus on altitude, etc. for a long period of time.

A couple of observations and comments about what I learned.  One, this confirms my SOP that I do not use the autopilot in the initial climb phase in IMC.  Two, it confirms why I never depart an airport unless the weather is above minimums for the approach for the active runway.  Even at 200' ceilings it does give some time in visual conditions before being in the soup (albeit not much in a turbocharged Mooney).  Three, I can see how insidious a loss of vacuum could be and how easy it would be to get totally disoriented with conflicting information and sorting it out.  Four, if I did not have the warning light that was flashing away I would install one right away.  I was messing with the autopilot but finally it caught my attention.  Finally, I can really see the value of regular partial panel work.  Once I covered the artificial horizon it was surprisingly easy for me to transition to the electric turn coordinator for turns and VSI/altimeter for attitude.  I also played with the panel function on my 696 to see how that would work if I were in IMC.  Worked OK and would be great in a pinch but I would not want to have to rely on it for any length of time.

All in all I am really grateful this happened in VMC and I learned a few good lessons about what to expect and if it happens in IMC I will quickly recognize those symptons.  On another note, I had forgotten that the speed brakes run on vacuum and I sort of missed it when they dumped me down from 12,000 feet.  Was able to manage but it would have been nice to be able to dump some airspeed.  I could have popped on the standby but didn't really need to.

[thinwing]

ehscott..thanks for report ..very interesting the way the ai ran down.Since it also commands a/p I could see why you would intially be playing with a/p....what kind was it and why didnt it "flag" the a/p with an unreliable attitude input??If your backup vacumn pump is similar to mine,its just engaged by a clutch that is electrically engaged by a switch.Once you engaged it and got a vac. indication ,why did you turn it off again??Were you trying to save it from wear and tear??I dont think you need to because it is probably the same pump type as your main pump.Last questions...how many hours on main pump??thanks again kp couch

[Earl]

Quote: thinwing

ehscott..thanks for report ..very interesting the way the ai ran down.Since it also commands a/p I could see why you would intially be playing with a/p....what kind was it and why didnt it "flag" the a/p with an unreliable attitude input??If your backup vacumn pump is similar to mine,its just engaged by a clutch that is electrically engaged by a switch.Once you engaged it and got a vac. indication ,why did you turn it off again??Were you trying to save it from wear and tear??I dont think you need to because it is probably the same pump type as your main pump.Last questions...how many hours on main pump??thanks again kp couch

[thinwing]

ehscott...500hrs.....that is what I recall i would typically get from an airbourne pump on my Baron...The Bravo I fly now has about 900 hrs on the main pump and as you stated the standby is only switched on at beginning to test function.My main pump is only driving a standby aI...when I did the install of the g500 (gad 43 now drives the a/p)if I had installed an electric aI with its own backup lithium battery for redunacy to the main electrical bus,,,I could have done away with the vac pumps altogether...the only reason I didnt was I was already over budget and decided enough was enough.I will consider it though if I suffer a vac pump failure..sinc kp couch

[Cruiser]

just curious, did you report the failure to ATC? What did they say?

91.187   Operation under IFR in controlled airspace: Malfunction reports.

(a) The pilot in command of each aircraft operated in controlled airspace under IFR shall report as soon as practical to ATC any malfunctions of navigational, approach, or communication equipment occurring in flight.

( In each report required by paragraph (a) of this section, the pilot in command shall include the—

(1) Aircraft identification;

(2) Equipment affected;

(3) Degree to which the capability of the pilot to operate under IFR in the ATC system is impaired; and

(4) Nature and extent of assistance desired from ATC.

 

[Earl]

Quote: Cruiser

just curious, did you report the failure to ATC? What did they say?

91.187   Operation under IFR in controlled airspace: Malfunction reports.

(a) The pilot in command of each aircraft operated in controlled airspace under IFR shall report as soon as practical to ATC any malfunctions of navigational, approach, or communication equipment occurring in flight.

( In each report required by paragraph (a) of this section, the pilot in command shall include the—

(1) Aircraft identification;

(2) Equipment affected;

(3) Degree to which the capability of the pilot to operate under IFR in the ATC system is impaired; and

(4) Nature and extent of assistance desired from ATC.

 

[Earl]

Quote: thinwing

ehscott...500hrs.....that is what I recall i would typically get from an airbourne pump on my Baron...The Bravo I fly now has about 900 hrs on the main pump and as you stated the standby is only switched on at beginning to test function.My main pump is only driving a standby aI...when I did the install of the g500 (gad 43 now drives the a/p)if I had installed an electric aI with its own backup lithium battery for redunacy to the main electrical bus,,,I could have done away with the vac pumps altogether...the only reason I didnt was I was already over budget and decided enough was enough.I will consider it though if I suffer a vac pump failure..sinc kp couch

[jpusser]

(a) The pilot in command of each aircraft operated in controlled airspace under IFR shall report as soon as practical to ATC any malfunctions of navigational, approach, or communication equipment occurring in flight.

I wouldn't consider an AI navigational, approach, or communication equipment

[Earl]

Quote: jpusser

(a) The pilot in command of each aircraft operated in controlled airspace under IFR shall report as soon as practical to ATC any malfunctions of navigational, approach, or communication equipment occurring in flight.

I wouldn't consider an AI navigational, approach, or communication equipment

[ChrisH]

AI is required equipment for IFR flight as is a DG, with your back-up turned off you had neither and were still flying IFR. Note FAR 91.205 refers to IFR not IMC. I'm no expert, but I'd say you should have flown w/ backup on or gone VFR to stay legal.

 

Chris.

[Earl]

Quote: ChrisH

AI is required equipment for IFR flight as is a DG, with your back-up turned off you had neither and were still flying IFR. Note FAR 91.205 refers to IFR not IMC. I'm no expert, but I'd say you should have flown w/ backup on or gone VFR to stay legal.

 

Chris.

[thinwing]

eh scott..I think it would have been another 3amu...I didnot install it cause it was just for a backup AI, of which I only occasionally include it in my instrument scan...its amazing how much my basic scan has been simplified by the g500...not sure if I could go back to steam..kpc

[Jeff_S]

Best rationale ever for a rate-based autopilot system. Not that they are fool proof, either, as my S-TEC System 55x relies on a special turn coordinator which I did have to replace this summer. But there's definitely safety in multiple backups. I noticed my vacuum reading on a flight Saturday was down near the bottom of the green arc where normally its square in the middle. ~400 hours on this pump, according to the logs, so it may be starting to go as well.

[Earl]

Quote: Jeff_S

Best rationale ever for a rate-based autopilot system. Not that they are fool proof, either, as my S-TEC System 55x relies on a special turn coordinator which I did have to replace this summer. But there's definitely safety in multiple backups. I noticed my vacuum reading on a flight Saturday was down near the bottom of the green arc where normally its square in the middle. ~400 hours on this pump, according to the logs, so it may be starting to go as well.

[Cruiser]

excellent example of why you should include practicing partial panel hand flying when you do your currency work every six months.

[Earl]

Quote: Cruiser

excellent example of why you should include practicing partial panel hand flying when you do your currency work every six months.

[carusoam]

Speaking of use it or lose it....

I too have the back up, electric powered vacuum pump.  The only exercise it gets is during the pre-flight. 

There really isn't a way to exercise it more often.  It would be unusual to run two pumps at one time....

Is anyone familiar with a failure of the back-up pump system.  Mine is near 15 years old....(added early in the plane's life).

Best regards,

-a-

[Earl]

Quote: carusoam

Speaking of use it or lose it....

I too have the back up, electric powered vacuum pump.

[LT4BIRD]

Dont use the Rappco overhauled units. They tend to fail more than normal.

Have you ever noticed the shaft always fails even though the pump isnt bad. 

[Earl]

Quote: LT4BIRD

Dont use the Rappco overhauled units. They tend to fail more than normal.

Have you ever noticed the shaft always fails even though the pump isnt bad.