Question about FAR's for Altitude Reporting

[lr172]

I was getting a guy set up to do my Static test for IFR certification and he told me I needed a TSO'ed altimeter for that certification. I had never heard that, so now doing research. He quoted me 91.217, among others, and I read it. It seems to state that an altitude encoder must be TSO'ed in order to hook it up to a transponder as an altituder source. I use the Dynon encoder, so was somewhat concerned. Does anyone have any experience with this issue/reg? Maybe the use of "meet the standard of..." allows non-TSO'ed units.

Here is the text of 91.217:

91.217 Data correspondence between automatically reported pressure altitude data and the pilot's altitude reference.
(a) No person may operate any automatic pressure altitude reporting equipment associated with a radar beacon transponder -

(1) When deactivation of that equipment is directed by ATC;

(2) Unless, as installed, that equipment was tested and calibrated to transmit altitude data corresponding within 125 feet (on a 95 percent probability basis) of the indicated or calibrated datum of the altimeter normally used to maintain flight altitude, with that altimeter referenced to 29.92 inches of mercury for altitudes from sea level to the maximum operating altitude of the aircraft; or

(3) Unless the altimeters and digitizers in that equipment meet the standards of TSO-C10b and TSO-C88, respectively.

(b) No person may operate any automatic pressure altitude reporting equipment associated with a radar beacon transponder or with ADS-B Out equipment unless the pressure altitude reported for ADS-B Out and Mode C/S is derived from the same source for aircraft equipped with both a transponder and ADS-B Out.

[ChiefPilot]

"Unless the altimeters and digitizers in that equipment meet the standards of TSO-C10b and TSO-C88, respectively."

That means the equipment needs to meet the performance levels identified in those standards, but does not require that the equipment is actually TSO'd. Find another shop to do the test - I can recommend Steinair but that might be a bit more of a hike than you'd like.

[Raymo]

This thread should help...

http://www.vansairforce.com/communit...ad.php?t=42657

[Auburntsts]

Look at at the end of sub para 2 - there's an "or". IOW if you don't do the calibration outline in sub-par 2, then the TSO req applies IAW sub-par 3.

So no, the altimeter doesn't have to be TSO'd if the shop does the calibration.

[bret]

more info

http://dynonavionics.com/cgi-bin/yab...m=1412722560/6

[Walt]

Bottom line, encoding altimeters (glass panels) and encoders do NOT have to carry a TSO in EAB aircraft, they do have to be tested to ensure they meet the spec in 91.217 (and 91.411/91.413 for the other IFR stuff).