"Eric Greenwell" wrote in message
news:chOJg.10062$XD1.1965@trnddc01...
BTIZ wrote:

BT

"flying_monkey" wrote in message
oups.com...
wrote:
. . . snip . . .
If you put a transponder in your glider - either with or without an
encoder - it needs to be calibrated and so noted in your aircraft log
book. You are then required to have checked every twenty-four months.
If you are going to put a transponder in the glider, then spring for an
encoder - In for a penny, in for a pound and all that. Without the
encoder ATC as well as TCAS only gets azimuth and range. With the
encoder you get the third demension, altitude.
Sure beats ending up in Denver as a pitot cover on a B-767!

Billy Hill, Zulu
Zulu,

Having owned a few junky older airplanes (like old Bonanzas) with only
Mode A transponders, I can't recall any requirement for calibration or
any recurrent inspection of these. If you're flying IFR, you have to
have a pitot/static check every two years, and if you have Mode C, you
have to have the encoder calibrated, but I wasn't aware of anything
other than that.

91.413(a) requires 24 month inspection of any transponder to be used in
airspace defined by 91.215

It makes no reference to VFR or IFR flight.

I can't find any reference in 91.413(a) to encoder calibration, and when I
have the required 2 year test done, only the encoder reading at field
elevation is checked. So, I don't think the encoder calibration check is
required for VFR operation. Do you know of a regulation requiring it?

--
Change "netto" to "net" to email me directly

Eric Greenwell - Washington State, USA

www.motorglider.org - Download "A Guide to Self-launching Sailplane
Operation"

Eric, you are correct.. the encoder for altitude calibration is not in
91.413(a), that part is in 91.411 and 91.411 only refers to IFR
requirements, not VFR.

The 91.413(a) check verifies that the 4096 code dialed in is the code
transmitted and has nothing to do with altitude.

VFR only aircraft require 91.413 every 24 months..
IFR capable aircraft require 91.413 and 91.411 every 24 months..

So if you have the encoder and plan to go into Class A airspace... is the
91.411 required in a VFR only aircraft?

It's all part of the same check.. when you get the 91.413 done, and you have
an encoder, get the 94.411 done. The 91.411 also includes a pitot static
check.

BT