Matt,

 

Interesting.  That brought to mind the trip returning home from the Reno Air races interrupted by 9/11.  Over Wyoming I was in, uh, very electrical clouds when the S-Tec 50 auto pilot shut off, communications were very difficult with static and my hydro-electric analog being was tingling all over.  The Terra radios, Garmin 430, Rocky Mountain encoder, AOA and Vision Micro Systems EPI 800 all continued to work along with the vacuum powered AI and DG.  Oh yeah, the 12th century compass and old fashioned airspeed indicator also remained operational.

 

Whilst considering another 1000 IFR miles, my mind became re-focused on a  giant hole that opened up over Casper WY and where ATC allowed me to land as there were no local terrorrist targets of value.  Why land there? You might ask.  Well, I had lost my vacuum system backup, the auto pilot.  Or was it that I was relying soley on my a/p backup, the vacuum driven AI.   Anyway, I try to fix such things as they break rather than succumb to get-home-itis.

 

How fortunate that the Casper avionics shop was knowledgeable with S-Tec and at least fixed the pitch board blown fuse overnight.  Of course it took a few months to determine that there were other problems with the pitch board that eventually required its replacement. 

 

So, 1 electric TSo'd item failed but all the rest kept on ticking, including those of questionable origins.  However, I have always bought the argument for a mixed power source panel, such as electric and vacuum.  Part of my decision to land was that my friend had lost his vacuum pump on the way to Reno and the Fed Ex plane carrying his replacement pump was one of the last to land at Reno.  Remembering his pump failure, the miracle hole and qualified avionics shop all came together at the right moment.

 

Scott Krueger      

 

Just a quick anecdotal story regarding TSO vs. non-TSO equipment:

 About 7 years ago I was flying my Lancair 360 out of Aspen during marginal weather.  It was a challenging departure that has you flying in a valley on instruments.  Not a great time for instrument failure.

 About 2 minutes into the departure, solid IFR, I started getting severe p-static.  So severe my headset was shocking me badly enough that I had to remove it.  Here is the important part…

Every non-TSO piece of electrical equipment in the plane failed.  Not one TSO piece of equipment failed.  Here is list of what failed:

 -          AOA.  Started bouncing up and down and calling out “error …”

-          VM Engine instruments

-          Rocky Mountain MicroEncoder.  Shut off.

-          Tablet PC (used for charts): shut off (fortunately I had back-up)

-          CO detector.  Permanently damaged

 

Here is what did not fail:

 

-          Mechanical/steam gauges

-          Sandel EFIS

-          Garmin 430’s (2)

-          Garmin audio panel

-          Garmin transponder

-          S-TEC autopilot

 

It seems likely I wouldn’t be writing this email today if I had all electronic non-TSO equipment that day…

 

Matt