Vacuum Failure

[ripnet]

Flew a long solo XC today (student here), and on my final leg my vacuum pump decided to fail. No issues with the flight or anything; no clouds unlimited vis, etc.

A few days ago, my instructor was flying a different plane and the vacuum pump failed while shooting an ILS.

My question: is this a common failure? I've been flying for 30-something hours and I've encountered one, and so did my instructor, all within a short period of time. Really want more partial panel training now.

 

[Fearless Tower]

My question: is this a common failure? I've been flying for 30-something hours and I've encountered one, and so did my instructor, all within a short period of time. Really want more partial panel training now.

They happen. You should always be prepared, but not really that common.

I've had one single vacuum pump failure (discovered on start-up) in over 900 hours of flying. It was in a twin; non-event. Although, even for the single engine airplanes, nowadays, with portable GPS units and things like AHRS systems on ipads, a vacuum pump failure is not as potentially dangerous as it used to be.

 

[steingar]

They're machines, and they break. I just found a little panel thingie on my iPad. I bet the tablet's accelerometers are more accurate than at the AI's gyros too.

 

[Caramon13]

Had one fail on me too, at the start of a 2 hour fly down to KEYW. Rather than make it VFR I opted to turn around and go back. Was a bummer too because I was with my dad and he packed a snack for the trip, posted he was going and seemed super excited about it.

Though, the pump that was in there had been there for almost exactly 1000 hours, which is the limit of most pumps.

 

[Skip Miller]

Just remember that losing the vacuum pump will also fail your autopilot, if it takes information from your vacuum AI.

-Skip

 

[jordane93]

I've had one vacuum failure and it occurred before I even taxied out. After you fly for a while, things will go wrong

 

[oilburner]

Had a vacuum pump fail once with about 1100 hrs on it. Not a prob this time for me since it only drove the stby horizon while on a trip while VMC.

They're cheap -- old pilots change them out at around 1000 hrs, I was told.

 

[FORANE]

They're cheap -- old pilots change them out at around 1000 hrs, I was told.

I would change it at 800 if flying IFR and relying on it for primary flight instrumentation.

Having had a couple of them apart, I buy Sigma Tec vacuum pumps. The Sigma Tec has sturdy carbon fiber looking vanes as compared to the fragile vanes made of pencil lead like carbon I have seen in some other pumps.
By looking into the ports of the Sigma Tec, one can see the vanes and judge the amount of wear.

 

[James331]

It happens, cheap rebuild from Kelly.

Chasing a failing AImeill out you into a nice gradual spiral

 

[Dan Thomas]

There's no reason to risk pump failure anymore. Both Rapco and Tempest make pumps with vane inspection ports. I prefer the Tempest, since the Rapco requires a special plastic measuring tool that comes with the pump but someone has to keep track of it, and the port for it is plugged by a really short setscrew that has about two threads on it that strip easily. Tempest uses a 3/8" pipe plug, and there's a reference hole behind it that allows you to gauge the vane wear. First check at 600 hours, then every 100 hours thereafter. Takes maybe three minutes.

The pumps have a small plastic drive coupling that shears if the pump fails and seizes. It gets old and the manufacturers want it replaced at six years.

Almost all failed pumps do so because they are ignored, just like any other component.

Continental engines spin their pumps faster than Lycomings, so they wear out sooner.

I wouldn't trust any Kelly rebuild. Their reputation hasn't been stellar on the other stuff they do.